Objective
Introduction
Wind Power Potential
Project Phase-I
Gharo Wind Corridor
Project Phase-II
Phase-II Results
Why Wind Energy..?
Energy Production
Data Collection
Project Reports
Contact Us
HOME
Pakistan Meteorological Department has conducted a detailed Wind Power Potential Survey of Coastal Areas of Pakistan and Ministry of Science and Technology has provided the required funding for this purpose. This study has enabled us to identify the potential areas where economically feasible wind farm can be established. One interesting aspect of this study is that contrary to the general impression, Sindh coastal areas have greater wind power potential than Balochistan coastal areas. Potential areas cover 9700 sq.km in Sindh. The gross wind power potential of this area is 43000 MW and keeping in view the area utilization constrains etc. the exploitable electric power generation potential of this area is estimated to be about 11000MW.
Feasibility study for the installation of 18 MW Model wind power project is prepared. Total cost of the project is estimated to be about Rs. 850 million and the pay back period would be 7-8 years. The levelised cost of power generation is estimated as Rs. 2.9/kwh.
Introduction:
The demand for energy has increased in tremendous proportions in the last few decades in Pakistan; the same is expected to increase further in the coming years. The primary sources of energy available in Pakistan are oil, natural gas, hydro and nuclear Power. At present oil accounts for approximately 45% of total commercial energy supply. The share of natural gas is 34% while that of hydel power remains roughly at 15%. The increase in cost of fossil fuel and the various environmental problems of large scale power generation have lead to increased appreciation of the potential of electricity generation from non-conventional sources. This has provided the planners and economists to find out other low cost energy resources.
Wind and Solar energies are the possible clean and low cost renewable resources available in the country. The potential, for the use of alternative technologies, has never been fully explored in Pakistan. Wind power provides opportunity to reduce dependence on imported fossil fuel and at the same time expands the power supply capacity to remote locations where grid expansion is not practical.
Recently conducted survey of Wind Power Potential along coastal areas of the country by Pakistan Meteorological Department (PMD), indicates that a potential exists for harvesting wind energy using currently available technologies, especially along Sindh coast.
Gharo, one of the sites in Sindh where the wind data have been recorded and studied by PMD, has been selected for this feasibility study. The wind measurements at Gharo have been carried out during 24 months period. The annual mean wind speed is estimated to be 6.86m/s at 50 meter above ground level. The annual power density of area is 408.6 W/m2, which bring the site into good category of power potential, which means this area is suitable for large economically viable wind farm.
Using the measured wind data the annual gross energy production by an 18 MW wind farm consisting of thirty – 600 kW turbines will be 45 million kWh. Taking into account the wind turbine availability, net losses and wake effects in the wind farm the net annual energy production is estimated to 31 million kWh per year corresponding to a capacity factor of 28%.
The total investment will be Rs: 850 million and pay back period will be 7-8 years. The capital cost of wind power projects ranges Rs 4 to 5 crore per MW. This gives a levelised cost of wind energy generation in the range of Rs: 2.50 to 3.00 per kWh, taking into consideration the fiscal benefits extended by the government.
Performance
Generally wind farm located in area with good winds and having a typical value of capacity factor i.e. 25% at least are economically viable. A typical life of wind turbine is 20 to 25 years. Maintenance is required at 6 months interval.
The total investment for the proposed project is Rs: 850 million and pay back period 7-8 years. The capital cost of a typical wind power project ranges Rs 4 to5 crore per MW. This gives a levelised cost of wind energy generation in the range of Rs: 2.5 to 3.00 per kWh, taking into consideration the fiscal benefits extended by the government. Different economic aspects of the project are shown in table 4, 5 & 6.
Risks Associated with Investments in Wind Power
i. The returns from investments in this sector are very dependent on government policies, both in terms of the incentives given and the taxation structure imposed on businesses. Hence changes in either are a source of concern to the investors. For example, changes in the tax laws that make all companies liable to pay a minimum tax on their profits, may negatively affect the wind program because it reduces the benefit from the tax shelter that investments here could provide.
ii. The main “fuel” controlling generation in any year is the wind speed. This is beyond the investor’s control: there is always the risk that actual generation in any year could be below the expected level.
iii. Grid availability to evacuate the generated power is an essential requirement. Poor grid availability and reliability are again risks that have to be borne by the investors under the current situation.
Wind Potential Area of Sindh
Total Area of Sindh suitable for wind farms = 9749 km2
Average Capacity Factor of this area in Sindh = 25%
Wind power potential of 18MW Wind Farm on 1 km2 area when Capacity Factor is 25% =18x0.25=4.5 MW
Gross Potential of the area corresponding to 25%Capacity Factor=9749x 4.5=43871 MW
Exploitable Potential ( 25% of the area) ≈ 11000 MW
The Benefits of Wind Energy
Wind energy is an ideal renewable energy because:
1. it is a pollution-free, infinitely sustainable form of energy
2. it doesn’t require fuel
3. it doesn’t create greenhouse gasses it doesn’t produce toxic or radioactive waste.
Wind energy is quiet and does not present any significant hazard to birds or other wildlife.
When large arrays of wind turbines are installed on farmland, only about 2% of the land area is required for the wind turbines.
The rest is available for farming, livestock, and other uses.
Landowners often receive payment for the use of their land, which enhances their income and increases the value of the land.
Ownership of wind turbine generators by individuals and the community allows people to participate directly in the preservation of our environment.
Each megawatt-hour of electricity that is generated by wind energy helps to reduce 0.8 to 0.9 tones of greenhouse gas emissions that are produced by coal or diesel fuel generation each year.
Copyright © 2008 Pakistan Meteorological Department. All Rights Reserved.
Webmaster : asfand@ndmc.gov.pk
Pakistan Meteorological Department
WIND ENERGY PROJECT
A Project funded by Ministry of Science & Technology
Why Wind energy...?
Friday, November 20, 2009
wilnd power
Wikipedia is there when you need it — now it needs you. $0.9M USD$7.5M USDDonate Now[Hide][Show]Wikipedia Forever Our shared knowledge. Our shared treasure. Help us protect it. [Show]Wikipedia Forever Our shared knowledge. Our shared treasure. Help us protect it. Wind power
From Wikipedia, the free encyclopedia
Jump to: navigation, search
A Wind turbine.Renewable energy
Biofuel
Biomass
Geothermal
Hydroelectricity
Solar energy
Tidal power
Wave power
Wind power
v • d • e
Wind power is the conversion of wind energy into a useful form of energy, such as electricity, using wind turbines. At the end of 2008, worldwide nameplate capacity of wind-powered generators was 121.2 gigawatts (GW).[1] In 2008, wind power produced about 1.5% of worldwide electricity usage;[1][2] and is growing rapidly, having doubled in the three years between 2005 and 2008. Several countries have achieved relatively high levels of wind power penetration, such as 19% of stationary electricity production in Denmark, 11% in Spain and Portugal, and 7% in Germany and the Republic of Ireland in 2008. As of May 2009, eighty countries around the world are using wind power on a commercial basis.[2]
Large-scale wind farms are connected to the electric power transmission network; smaller facilities are used to provide electricity to isolated locations. Utility companies increasingly buy back surplus electricity produced by small domestic turbines. Wind energy as a power source is attractive as an alternative to fossil fuels, because it is plentiful, renewable, widely distributed, clean, and produces no greenhouse gas emissions. However, the construction of wind farms is not universally welcomed because of their visual impact and other effects on the environment.
Wind power is non-dispatchable, meaning that for economic operation, all of the available output must be taken when it is available. Other resources, such as hydropower, and standard load management techniques must be used to match supply with demand. The intermittency of wind seldom creates problems when using wind power to supply a low proportion of total demand.[3][4]
Contents [hide]
1 History
2 Wind energy
2.1 Distribution of wind speed
3 Electricity generation
3.1 Grid management
3.2 Capacity factor
3.3 Penetration
3.4 Intermittency and penetration limits
3.5 Capacity credit and fuel saving
4 Turbine placement
5 Wind power usage
6 Small-scale wind power
7 Economics and feasibility
7.1 Full costs and lobbying
7.2 Relative cost of electricity by generation source
7.3 Growth and cost trends
7.4 Theoretical potential - World
7.5 Theoretical potential - UK
7.6 Direct costs
7.7 External costs
7.8 Incentives
8 Environmental effects
9 See also
10 References
11 External links
11.1 Wind power projects
[edit] History
Main article: History of wind power
Medieval depiction of a windmill
Windmills are typically installed in favourable windy locations. In the image, generators in SpainHumans have been using wind power for at least 5,500 years to propel sailboats and sailing ships, and architects have used wind-driven natural ventilation in buildings since similarly ancient times. Windmills have been used for irrigation pumping and for milling grain since the 7th century AD.
In the United States, the development of the "water-pumping windmill" was the major factor in allowing the farming and ranching of vast areas otherwise devoid of readily accessible water. Windpumps contributed to the expansion of rail transport systems throughout the world, by pumping water from water wells for the steam locomotives.[5] The multi-bladed wind turbine atop a lattice tower made of wood or steel was, for many years, a fixture of the landscape throughout rural America. When fitted with generators and battery banks, small wind machines provided electricity to isolated farms.
In July 1887, a Scottish academic, Professor James Blyth, undertook wind power experiments that culminated in a UK patent in 1891.[6] In the United States, Charles F. Brush produced electricity using a wind powered machine, starting in the winter of 1887-1888, which powered his home and laboratory until about 1900. In the 1890s, the Danish scientist and inventor Poul la Cour constructed wind turbines to generate electricity, which was then used to produce hydrogen.[6] These were the first of what was to become the modern form of wind turbine.
Small wind turbines for lighting of isolated rural buildings were widespread in the first part of the 20th century. Larger units intended for connection to a distribution network were tried at several locations including Yalta in 1931 and in Vermont in 1941.
The modern wind power industry began in 1979 with the serial production of wind turbines by Danish manufacturers Kuriant, Vestas, Nordtank, and Bonus. These early turbines were small by today's standards, with capacities of 20–30 kW each. Since then, they have increased greatly in size, while wind turbine production has expanded to many countries.
[edit] Wind energy
Further information: Wind
Distribution of wind speed (red) and energy (blue) for all of 2002 at the Lee Ranch facility in Colorado. The histogram shows measured data, while the curve is the Rayleigh model distribution for the same average wind speed. Energy is the Betz limit through a 100 m (328 ft) diameter circle facing directly into the wind. Total energy for the year through that circle was 15.4 gigawatt-hours (GWh).The Earth is unevenly heated by the sun, such that the poles receive less energy from the sun than the equator; along with this, dry land heats up (and cools down) more quickly than the seas do. The differential heating drives a global atmospheric convection system reaching from the Earth's surface to the stratosphere which acts as a virtual ceiling. Most of the energy stored in these wind movements can be found at high altitudes where continuous wind speeds of over 160 km/h (99 mph) occur. Eventually, the wind energy is converted through friction into diffuse heat throughout the Earth's surface and the atmosphere.
The total amount of economically extractable power available from the wind is considerably more than present human power use from all sources.[7] An estimated 72 TW of wind power on the Earth potentially can be commercially viable,[8] compared to about 15 TW average global power consumption from all sources in 2005. Not all the energy of the wind flowing past a given point can be recovered (see Betz' law).
[edit] Distribution of wind speed
The strength of wind varies, and an average value for a given location does not alone indicate the amount of energy a wind turbine could produce there. To assess the frequency of wind speeds at a particular location, a probability distribution function is often fit to the observed data. Different locations will have different wind speed distributions. The Weibull model closely mirrors the actual distribution of hourly wind speeds at many locations. The Weibull factor is often close to 2 and therefore a Rayleigh distribution can be used as a less accurate, but simpler model.
Because so much power is generated by higher wind speed, much of the energy comes in short bursts. The 2002 Lee Ranch sample is telling;[9] half of the energy available arrived in just 15% of the operating time. The consequence is that wind energy from a particular turbine or wind farm does not have as consistent an output as fuel-fired power plants; utilities that use wind power provide power from starting existing generation for times when the wind is weak thus wind power is primarily a fuel saver rather than a capacity saver. Making wind power more consistent requires that various existing technologies and methods be extended, in particular the use of stronger inter-regional transmission lines to link widely distributed wind farms. Problems of variability are addressed by grid energy storage, batteries, pumped-storage hydroelectricity and energy demand management.[10]
[edit] Electricity generation
Typical components of a wind turbine (gearbox, rotor shaft and brake assembly) being lifted into positionIn a wind farm, individual turbines are interconnected with a medium voltage (usually 34.5 kV) power collection system and communications network. At a substation, this medium-voltage electrical current is increased in voltage with a transformer for connection to the high voltage electric power transmission system.
The surplus power produced by domestic microgenerators can, in some jurisdictions, be fed back into the network and sold back to the utility company, producing a retail credit for the consumer to offset their energy costs.[11][12]
[edit] Grid management
Induction generators, often used for wind power projects, require reactive power for excitation so substations used in wind-power collection systems include substantial capacitor banks for power factor correction. Different types of wind turbine generators behave differently during transmission grid disturbances, so extensive modelling of the dynamic electromechanical characteristics of a new wind farm is required by transmission system operators to ensure predictable stable behaviour during system faults (see: Low voltage ride through). In particular, induction generators cannot support the system voltage during faults, unlike steam or hydro turbine-driven synchronous generators. Doubly-fed machines—wind turbines with solid-state converters between the turbine generator and the collector system—generally have more desirable properties for grid interconnection. Transmission systems operators will supply a wind farm developer with a grid code to specify the requirements for interconnection to the transmission grid. This will include power factor, constancy of frequency and dynamic behaviour of the wind farm turbines during a system fault.[13][14]
[edit] Capacity factor
Worldwide installed capacity 1997–2008, with projection 2009–13 based on an exponential fit. Data source: WWEASince wind speed is not constant, a wind farm's annual energy production is never as much as the sum of the generator nameplate ratings multiplied by the total hours in a year. The ratio of actual productivity in a year to this theoretical maximum is called the capacity factor. Typical capacity factors are 20–40%, with values at the upper end of the range in particularly favourable sites.[15] For example, a 1MW turbine with a capacity factor of 35% will not produce 8,760 MWh in a year (1 × 24 × 365), but only 1 × 0.35 × 24 × 365 = 3,066 MWh, averaging to 0.35 MW. Online data is available for some locations and the capacity factor can be calculated from the yearly output.[16][17]
Unlike fueled generating plants, the capacity factor is limited by the inherent properties of wind. Capacity factors of other types of power plant are based mostly on fuel cost, with a small amount of downtime for maintenance. Nuclear plants have low incremental fuel cost, and so are run at full output and achieve a 90% capacity factor. Plants with higher fuel cost are throttled back to follow load. Gas turbine plants using natural gas as fuel may be very expensive to operate and may be run only to meet peak power demand. A gas turbine plant may have an annual capacity factor of 5–25% due to relatively high energy production cost.
According to a 2007 Stanford University study published in the Journal of Applied Meteorology and Climatology, interconnecting ten or more wind farms can allow an average of 33% of the total energy produced to be used as reliable, baseload electric power, as long as minimum criteria are met for wind speed and turbine height.[18][19]
[edit] Penetration
Wind energy "penetration" refers to the fraction of energy produced by wind compared with the total available generation capacity. There is no generally accepted "maximum" level of wind penetration. The limit for a particular grid will depend on the existing generating plants, pricing mechanisms, capacity for storage or demand management, and other factors. An interconnected electricity grid will already include reserve generating and transmission capacity to allow for equipment failures; this reserve capacity can also serve to regulate for the varying power generation by wind plants. Studies have indicated that 20% of the total electrical energy consumption may be incorporated with minimal difficulty.[20] These studies have been for locations with geographically dispersed wind farms, some degree of dispatchable energy, or hydropower with storage capacity, demand management, and interconnection to a large grid area export of electricity when needed. Beyond this level, there are few technical limits, but the economic implications become more significant. Electrical utilities continue to study the effects of large (20% or more) scale penetration of wind generation on system stability and economics.[21][22][23][24]
At present, a few grid systems have penetration of wind energy above 5%: Denmark (values over 19%), Spain and Portugal (values over 11%), Germany and the Republic of Ireland (values over 6%). For instance, in the morning hours of 8 November 2009, wind wind power energy produced covered more than half the electricity demand in Spain during the early morning hours, setting a new record, and without problems for the network [25].
The Danish grid is heavily interconnected to the European electrical grid, and it has solved grid management problems by exporting almost half of its wind power to Norway. The correlation between electricity export and wind power production is very strong.[26]
[edit] Intermittency and penetration limits
Main article: Intermittent Power Sources
See also: Wind Power Forecasting
Diagram of the TVA pumped storage facility at Raccoon Mountain Pumped-Storage PlantElectricity generated from wind power can be highly variable at several different timescales: from hour to hour, daily, and seasonally. Annual variation also exists, but is not as significant. Related to variability is the short-term (hourly or daily) predictability of wind plant output. Like other electricity sources, wind energy must be "scheduled". Wind power forecasting methods are used, but predictability of wind plant output remains low for short-term operation.
Because instantaneous electrical generation and consumption must remain in balance to maintain grid stability, this variability can present substantial challenges to incorporating large amounts of wind power into a grid system. Intermittency and the non-dispatchable nature of wind energy production can raise costs for regulation, incremental operating reserve, and (at high penetration levels) could require an increase in the already existing energy demand management, load shedding, or storage solutions or system interconnection with HVDC cables. At low levels of wind penetration, fluctuations in load and allowance for failure of large generating units requires reserve capacity that can also regulate for variability of wind generation. Wind power can be replaced by other power stations during low wind periods. Transmission networks must already cope with outages of generation plant and daily changes in electrical demand. Systems with large wind capacity components may need more spinning reserve (plants operating at less than full load).[27][28]
A series of detailed modelling studies which looked at the Europe wide adoption of renewable energy and interlinking power grids using HVDC cables, indicates that the entire power usage could come from renewables, with 70% total energy from wind at the same sort of costs or lower than at present. Intermittency would be dealt with, according to this model, by a combination of geographic dispersion to de-link weather system effects, and the ability of HVDC to shift power from windy areas to non-windy areas.[29][30]
Pumped-storage hydroelectricity or other forms of grid energy storage can store energy developed by high-wind periods and release it when needed.[31] Stored energy increases the economic value of wind energy since it can be shifted to displace higher cost generation during peak demand periods. The potential revenue from this arbitrage can offset the cost and losses of storage; the cost of storage may add 25% to the cost of any wind energy stored, but it is not envisaged that this would apply to a large proportion of wind energy generated. Thus, the 2 GW Dinorwig pumped storage plant adds costs to nuclear energy in the UK for which it was built, but not to all the power produced from the 30 or so GW of nuclear plants in the UK.
In particular geographic regions, peak wind speeds may not coincide with peak demand for electrical power. In the US states of California and Texas, for example, hot days in summer may have low wind speed and high electrical demand due to air conditioning. Some utilities subsidize the purchase of geothermal heat pumps by their customers, to reduce electricity demand during the summer months by making air conditioning up to 70% more efficient;[32] widespread adoption of this technology would better match electricity demand to wind availability in areas with hot summers and low summer winds. Another option is to interconnect widely dispersed geographic areas with an HVDC "Super grid". In the USA it is estimated that to upgrade the transmission system to take in planned or potential renewables would cost at least $60 billion[33]. Total annual US power consumption in 2006 was 4 thousand billion kWh.[34] Over an asset life of 40 years and low cost utility investment grade funding, the cost of $60 billion investment would be about 5% p.a. (i.e. $3 billion p.a.) Dividing by total power used gives an increased unit cost of around $3,000,000,000 × 100 / 4,000 × 1 exp9 = 0.075 cent/kWh.
In the UK, demand for electricity is higher in winter than in summer, and so are wind speeds.[35][36] Solar power tends to be complementary to wind.[37][38] On daily to weekly timescales, high pressure areas tend to bring clear skies and low surface winds, whereas low pressure areas tend to be windier and cloudier. On seasonal timescales, solar energy typically peaks in summer, whereas in many areas wind energy is lower in summer and higher in winter.[39] Thus the intermittencies of wind and solar power tend to cancel each other somewhat. A demonstration project at the Massachusetts Maritime Academy shows the effect.[40] The Institute for Solar Energy Supply Technology of the University of Kassel pilot-tested a combined power plant linking solar, wind, biogas and hydrostorage to provide load-following power around the clock, entirely from renewable sources.[41]
A report from Denmark noted that their wind power network was without power for 54 days during 2002.[42] Wind power advocates argue that these periods of low wind can be dealt with by simply restarting existing power stations that have been held in readiness or interlinking with HVDC.[29]
Three reports on the wind variability in the UK issued in 2009, generally agree that variability of wind needs to be taken into account, but it does not make the grid unmanageable; and the additional costs, which are modest, can be quantified.[43]
A 2006 International Energy Agency forum presented costs for managing intermittency as a function of wind-energy's share of total capacity for several countries, as shown:
Increase in system operation costs, Euros per MWH, for 10% and 20% wind share[3]
10% 20%
Germany 2.5 3.2
Denmark 0.4 0.8
Finland 0.3 1.5
Norway 0.1 0.3
Sweden 0.3 0.7
[edit] Capacity credit and fuel saving
Many commentators concentrate on whether or not wind has any "capacity credit" without defining what they mean by this and its relevance. Wind does have a capacity credit, using a widely accepted and meaningful definition, equal to about 20% of its rated output (but this figure varies depending on actual circumstances). This means that reserve capacity on a system equal in MW to 20% of added wind could be retired when such wind is added without affecting system security or robustness. But the precise value is irrelevant since the main value of wind, (in the UK, worth 5 times the capacity credit value[44]) is its fuel and CO2 savings.
[edit] Turbine placement
Main article: Wind farm
See also: Wind atlas
Good selection of a wind turbine site is critical to economic development of wind power. Aside from the availability of wind itself, other factors include the availability of transmission lines, value of energy to be produced, cost of land acquisition, land use considerations, and environmental impact of construction and operations. Off-shore locations may offset their higher construction cost with higher annual load factors, thereby reducing cost of energy produced. Wind farm designers use specialized wind energy software applications to evaluate the impact of these issues on a given wind farm design.[citation needed]
Wind power density (WPD) is a calculation of the effective power of the wind at a particular location.[45] A map showing the distribution of wind power density is a first step in identifying possible locations for wind turbines. In the United States, the National Renewable Energy Laboratory classifies wind power density into ascending classes. The larger the WPD at a location, the higher it is rated by class. Wind power classes 3 (300–400 W/m2 at 50 m altitude) to 7 (800–2000 W/m2 at 50 m altitude) are generally considered suitable for wind power development. There are 625,000 km2 in the contiguous United States that have class 3 or higher wind resources and which are within 10 km of electric transmission lines. If this area is fully utilized for wind power, it would produce power at the average continuous equivalent rate of 734 GWe. For comparison, in 2007 the US consumed electricity at an average rate of 474 GW,[46] from a total generating capacity of 1,088 GW.[47]
[edit] Wind power usage
Further information: Category:Wind power by country and Installed wind power capacity
Installed windpower capacity (MW)[1] # Nation 2005 2006 2007 2008
- European Union 40,722 48,122 56,614 65,255
1 United States 9,149 11,603 16,819 25,170
2 Germany 18,428 20,622 22,247 23,903
3 Spain 10,028 11,630 15,145 16,740
4 China 1,266 2,599 5,912 12,210
5 India 4,430 6,270 7,850 9,587
6 Italy 1,718 2,123 2,726 3,537
7 France 779 1,589 2,477 3,426
8 United Kingdom 1,353 1,963 2,389 3,288
9 Denmark 3,132 3,140 3,129 3,164
10 Portugal 1,022 1,716 2,130 2,862
11 Canada 683 1,460 1,846 2,369
12 Netherlands 1,236 1,571 1,759 2,237
13 Japan 1,040 1,309 1,528 1,880
14 Australia 579 817 817 1,494
15 Ireland 495 746 805 1,245
16 Sweden 509 571 831 1,067
17 Austria 819 965 982 995
18 Greece 573 758 873 990
19 Poland 83 153 276 472
20 Turkey 20 65 207 433
21 Norway 268 325 333 428
22 Egypt 145 230 310 390
23 Belgium 167 194 287 384
24 Taiwan 104 188 280 358
25 Brazil 29 237 247 339
26 New Zealand 168 171 322 325
27 South Korea 119 176 192 278
28 Bulgaria 14 36 57 158
29 Czech Republic 30 57 116 150
30 Finland 82 86 110 140
31 Hungary 18 61 65 127
32 Morocco 64 64 125 125
33 Ukraine 77 86 89 90
34 Mexico 2 84 85 85
35 Iran 32 47 67 82
Rest of Europe 141 204 233 261
Rest of Americas 155 159 184 210
Rest of Africa
& Middle East 52 52 51 56
Rest of Asia
& Oceania 27 27 27 36
World total (MW) 59,024 74,151 93,927 121,188
There are now many thousands of wind turbines operating, with a total nameplate capacity of 121,188 MWp of which wind power in Europe accounts for 55% (2008). World wind generation capacity more than quadrupled between 2000 and 2006, doubling about every three years. 81% of wind power installations are in the US and Europe. The share of the top five countries in terms of new installations fell from 71% in 2004 to 62% in 2006, but climbed to 73% by 2008 as those countries—the United States, Germany, Spain, China, and India—have seen substantial capacity growth in the past two years (see chart).
By 2010, the World Wind Energy Association expects 160GW of capacity to be installed worldwide,[48] up from 73.9 GW at the end of 2006, implying an anticipated net growth rate of more than 21% per year.
Denmark generates nearly one-fifth of its electricity with wind turbines—the highest percentage of any country—and is ninth in the world in total wind power generation. Denmark is prominent in the manufacturing and use of wind turbines, with a commitment made in the 1970s to eventually produce half of the country's power by wind.
In recent years, the US has added more wind energy to its grid than any other country, with a growth in power capacity of 45% to 16.8 GW in 2007[49] and surpassing Germany's nameplate capacity in 2008. California was one of the incubators of the modern wind power industry, and led the U.S. in installed capacity for many years; however, by the end of 2006, Texas became the leading wind power state and continues to extend its lead. At the end of 2008, the state had 7,116 MW installed, which would have ranked it sixth in the world if Texas was a separate country. Iowa and Minnesota each grew to more than 1 GW installed by the end of 2007; in 2008 they were joined by Oregon, Washington, and Colorado.[50] Wind power generation in the U.S. was up 31.8% in February, 2007 from February, 2006.[51] The average output of one MW of wind power is equivalent to the average electricity consumption of about 250 American households. According to the American Wind Energy Association, wind will generate enough electricity in 2008 to power just over 1% (equivalent to 4.5 million households) of total electricity in U.S., up from less than 0.1% in 1999. U.S. Department of Energy studies have concluded wind harvested in the Great Plains states of Texas, Kansas, and North Dakota could provide enough electricity to power the entire nation, and that offshore wind farms could do the same job.[52][53] In addition, the wind resource over and around the Great Lakes, recoverable with currently available technology, could by itself provide 80% as much power as the U.S. and Canada currently generate from non-renewable resources,[54] with Michigan's share alone equating to one third of current U.S. electricity demand.[55]
In 2005, China announced it would build a 1000 MW wind farm in Hebei for completion in 2020. China has set a generating target of 30,000 MW by 2020 from renewable energy sources — it says indigenous wind power could generate up to 253,000 MW.[56] A Chinese renewable energy law was adopted in November 2004, following the World Wind Energy Conference organized by the Chinese and the World Wind Energy Association. By 2008, wind power was growing faster in China than the government had planned, and indeed faster in percentage terms than in any other large country, having more than doubled each year since 2005. Policymakers doubled their wind power prediction for 2010, after the wind industry reached the original goal of 5 GW three years ahead of schedule.[57] Current trends suggest an actual installed capacity near 20 GW by 2010, with China shortly thereafter pursuing the United States for the world wind power lead.[57]
India ranks 5th in the world with a total wind power capacity of 9,587 MW in 2008,[1] or 3% of all electricity produced in India. The World Wind Energy Conference in New Delhi in November 2006 has given additional impetus to the Indian wind industry.[48] Muppandal village in Tamil Nadu state, India, has several wind turbine farms in its vicinity, and is one of the major wind energy harnessing centres in India led by majors like Suzlon, Vestas, Micon among others.[58][59]
Mexico recently opened La Venta II wind power project as an important step in reducing Mexico's consumption of fossil fuels. The 88 MW project is the first of its kind in Mexico, and will provide 13 percent of the electricity needs of the state of Oaxaca. By 2012 the project will have a capacity of 3500 MW.
Another growing market is Brazil, with a wind potential of 143 GW.[60] The federal government has created an incentive program, called Proinfa,[61] to build production capacity of 3300 MW of renewable energy for 2008, of which 1422 MW through wind energy. The program seeks to produce 10% of Brazilian electricity through renewable sources.
South Africa has a proposed station situated on the West Coast north of the Olifants River mouth near the town of Koekenaap, east of Vredendal in the Western Cape province. The station is proposed to have a total output of 100MW although there are negotiations to double this capacity. The plant could be operational by 2010.
France has announced a target of 12,500 MW installed by 2010, though their installation trends over the past few years suggest they'll fall well short of their goal.
Canada experienced rapid growth of wind capacity between 2000 and 2006, with total installed capacity increasing from 137 MW to 1,451 MW, and showing an annual growth rate of 38%.[62] Particularly rapid growth was seen in 2006, with total capacity doubling from the 684 MW at end-2005.[63] This growth was fed by measures including installation targets, economic incentives and political support. For example, the Ontario government announced that it will introduce a feed-in tariff for wind power, referred to as 'Standard Offer Contracts', which may boost the wind industry across the province.[64] In Quebec, the provincially owned electric utility plans to purchase an additional 2000 MW by 2013.[65]
Annual Wind Power Generation (TWh) and total electricity consumption(TWh) for 10 largest countries[1][66][67][68][69][70] Rank Nation 2005 2006 2007 2008
Wind
Power Capacity
Factor % Total
Power Wind
Power Capacity
Factor % Total
Power Wind
Power Capacity
Factor % Total
Power Wind
Power Capacity
Factor % Total
Power
1 United States 17.8 22.2% 0.4% 4048.9 26.6 26.1% 0.7% 4058.1 34.5 23.4% 0.8% 4149.9 52.0 23.5% 1.3% 4108.6
2 Germany 27.2 16.9% 5.1% 533.7 30.7 17.0% 5.4% 569.9 38.5 19.7% 6.6% 584.9
3 Spain 20.7 23.5% 7.9% 260.7 22.9 22.4% 8.5% 268.8 27.2 20.5% 9.8% 276.8 31.4 21.7% 11.1% 282.1
4 China 1.9 17.2% 0.1% 2474.7 3.7 16.2% 0.1% 2834.4 5.6 [71] 10.6% 0.2% 3255.9 12.8 [72] 12.0% 0.4% 3426.8
5 India 6.3 16.2% 0.9% 679.2 7.6 13.8% 1.0% 726.7 14.7 21.0% 1.9% 774.7
6 Italy 2.3 15.3% 0.7% 330.4 3.0 16.1% 0.9% 337.5 4.0[73] 16.7% 1.2% 339.9 4.9 15.7% 1.4% 339.5
7 France 0.9 13.6% 0.2% 482.4 2.2 16.0% 0.5% 478.4 4.0 18.6% 0.8% 480.3 5.6 18.8% 1.1% 494.5
8 United Kingdom 2.8 24.0% 0.7% 407.4 4.0 23.2% 1.0% 383.9 5.9 28.2% 1.5% 379.8
9 Denmark 6.6 24.0% 18.5% 35.7 6.1 22.2% 16.8% 36.4 7.2 26.3% 19.7% 36.4 6.9 24.9% 19.1% 36.2
10 Portugal 1.7 19.0% 3.6% 47.9 2.9 19.3% 5.9% 49.2 4.0 21.2% 8.0% 50.1 5.7 22.7% 11.3% 50.6
World total (TWh) 99.5 19.2% 0.6% 15,746.5[74] 124.9 19.2% 0.7% 16,790 17,480[75] 260[1] 24.5%[1] 1.5%[1]
[edit] Small-scale wind power
Further information: Microgeneration
This wind turbine charges a 12 V battery to run 12 V appliances.Small-scale wind power is the name given to wind generation systems with the capacity to produce up to 50 kW of electrical power.[76] Isolated communities, that may otherwise rely on diesel generators may use wind turbines to displace diesel fuel consumption. Individuals may purchase these systems to reduce or eliminate their dependence on grid electricity for economic or other reasons, or to reduce their carbon footprint. Wind turbines have been used for household electricity generation in conjunction with battery storage over many decades in remote areas.
5 Kilowatt Vertical Axis Wind TurbineGrid-connected wind turbines may use grid energy storage, displacing purchased energy with local production when available. Off-grid system users can either adapt to intermittent power or use batteries, photovoltaic or diesel systems to supplement the wind turbine. In urban locations, where it is difficult to obtain predictable or large amounts of wind energy (little is known about the actual wind resource of towns and cities [77]), smaller systems may still be used to run low-power equipment. Equipment such as parking meters or wireless Internet gateways may be powered by a wind turbine that charges a small battery, replacing the need for a connection to the power grid.
A new Carbon Trust study into the potential of small-scale wind energy has found that small wind turbines could provide up to 1.5 terawatt hours (TW·h) per year of electricity (0.4% of total UK electricity consumption), saving 0.6 million tonnes of carbon dioxide (Mt CO2) emission savings. This is based on the assumption that 10% of households would install turbines at costs competitive with grid electricity, around 12 pence (US 19 cents) a kWh.[78]
Distributed generation from renewable resources is increasing as a consequence of the increased awareness of climate change. The electronic interfaces required to connect renewable generation units with the utility system can include additional functions, such as the active filtering to enhance the power quality.[79]
[edit] Economics and feasibility
The neutrality of this section is disputed. Please see the discussion on the talk page. Please do not remove this message until the dispute is resolved. (September 2009)
Erection of an Enercon E70-4[edit] Full costs and lobbying
Commenting on the EU's 2020 renewable energy target, Helm (2009) is critical of how the costs of wind power are citied by lobbyists:[80]
For those with an economic interest in capturing as much of the climate-change pork barrel as possible, there are two ways of presenting the costs [of wind power] in a favourable light: first, define the cost base as narrowly as possible; and, second, assume that the costs will fall over time with R&D and large-scale deployment. And, for good measure, when considering the alternatives, go for a wider cost base (for example, focusing on the full fuel-cycle costs of nuclear and coal-mining for coal generation) and assume that these technologies are mature, and even that costs might rise (for example, invoking the highly questionable ‘peak oil hypothesis’).
A House of Lords Select Committee report (2008) on renewable energy in the UK says:[81]
We have a particular concern over the prospective role of wind generated and other intermittent sources of electricity in the UK, in the absence of a break-through in electricity storage technology or the integration of the UK grid with that of continental Europe. Wind generation offers the most readily available short-term enhancement in renewable electricity and its base cost is relatively cheap. Yet the evidence presented to us implies that the full costs of wind generation (allowing for intermittency, back-up conventional plant and grid connection), although declining over time, remain significantly higher than those of conventional or nuclear generation (even before allowing for support costs and the environmental impacts of wind farms). Furthermore, the evidence suggests that the capacity credit of wind power (its probable power output at the time of need) is very low; so it cannot be relied upon to meet peak demand. Thus wind generation needs to be viewed largely as additional capacity to that which will need to be provided, in any event, by more reliable means
Helm (2009) says that wind's problem of intermittent supply will probably lead to another dash-for-gas or dash-for-coal in Europe, possibly with a negative impact on energy security.[80]
[edit] Relative cost of electricity by generation source
See Relative cost of electricity generated by different sources
[edit] Growth and cost trends
Wind and hydroelectric power generation have negligible fuel costs and relatively low maintenance costs. Wind power has a low marginal cost and a high proportion of capital cost. The estimated average cost per unit incorporates the cost of construction of the turbine and transmission facilities, borrowed funds, return to investors (including cost of risk), estimated annual production, and other components, averaged over the projected useful life of the equipment, which may be in excess of twenty years. Energy cost estimates are highly dependent on these assumptions so published cost figures can differ substantially. A British Wind Energy Association report gives an average generation cost of onshore wind power of around 3.2 pence (between US 5 and 6 cents) per kWh (2005).[82] Cost per unit of energy produced was estimated in 2006 to be comparable to the cost of new generating capacity in the US for coal and natural gas: wind cost was estimated at $55.80 per MWh, coal at $53.10/MWh and natural gas at $52.50.[83] Other sources in various studies have estimated wind to be more expensive than other sources (see Economics of new nuclear power plants, Clean coal, and Carbon capture and storage).
In 2004, wind energy cost a fifth of what it did in the 1980s, and some expected that downward trend to continue as larger multi-megawatt turbines were mass-produced.[84] However, installed cost averaged €1,300 a kW in 2007,[85] compared to €1,100 a kW in 2005.[86] Not as many facilities can produce large modern turbines and their towers and foundations, so constraints develop in the supply of turbines resulting in higher costs.[87] Research from a wide variety of sources in various countries shows that support for wind power is consistently 70–80% among the general public.[88]
Global Wind Energy Council (GWEC) figures show that 2007 recorded an increase of installed capacity of 20 GW, taking the total installed wind energy capacity to 94 GW, up from 74 GW in 2006. Despite constraints facing supply chains for wind turbines, the annual market for wind continued to increase at an estimated rate of 37%, following 32% growth in 2006. In terms of economic value, the wind energy sector has become one of the important players in the energy markets, with the total value of new generating equipment installed in 2007 reaching €25 billion, or US$36 billion.[85]
Although the wind power industry will be impacted by the global financial crisis in 2009 and 2010, a BTM Consult five year forecast up to 2013 projects substantial growth. Over the past five years the average growth in new installations has been 27.6 percent each year. In the forecast to 2013 the expected average annual growth rate is 15.7 percent.[89][90] More than 200 GW of new wind power capacity could come on line before the end of 2013. Wind power market penetration is expected to reach 3.35 percent by 2013 and 8 percent by 2018.[89][90]
Existing generation capacity represents sunk costs, and the decision to continue production will depend on marginal costs going forward, not estimated average costs at project inception. For example, the estimated cost of new wind power capacity may be lower than that for "new coal" (estimated average costs for new generation capacity) but higher than for "old coal" (marginal cost of production for existing capacity). Therefore, the choice to increase wind capacity will depend on factors including the profile of existing generation capacity.
[edit] Theoretical potential - World
Map of available wind power for the United States. Color codes indicate wind power density class.Wind power available in the atmosphere is much greater than current world energy consumption. The most comprehensive study As of 2005[update][91] found the potential of wind power on land and near-shore to be 72 TW, equivalent to 54,000 MToE (million tons of oil equivalent) per year, or over five times the world's current energy use in all forms. The potential takes into account only locations with mean annual wind speeds ≥ 6.9 m/s at 80 m. The study assumes six 1.5 megawatt, 77 m diameter turbines per square kilometer on roughly 13% of the total global land area (though that land would also be available for other compatible uses such as farming). The authors acknowledge that many practical barriers would need to be overcome to reach this theoretical capacity.
The practical limit to exploitation of wind power will be set by economic and environmental factors, since the resource available is far larger than any practical means to develop it.
[edit] Theoretical potential - UK
A recent estimate gives the total potential average output for UK for various depth and distance from the coast. The maximum case considered was beyond 200 km from shore and in depths of 100 - 700 m necessitating floating wind turbines) and this gave an average resource of 2,000 GWe which is to be compared with the average UK demand of about 40 GWe.[92]
[edit] Direct costs
Many potential sites for wind farms are far from demand centres, requiring substantially more money to construct new transmission lines and substations. In some regions this is partly because frequent strong winds themselves have discouraged dense human settlement in especially windy areas. The wind which was historically a nuisance is now becoming a valuable resource, but it may be far from large populations which developed in areas more sheltered from wind.
Since the primary cost of producing wind energy is construction and there are no fuel costs, the average cost of wind energy per unit of production depends on a few key assumptions, such as the cost of capital and years of assumed service. The marginal cost of wind energy once a plant is constructed is usually less than 1 cent per kWh.[93] Since the cost of capital plays a large part in projected cost, risk (as perceived by investors) will affect projected costs per unit of electricity.
The commercial viability of wind power also depends on the price paid to power producers. Electricity prices are highly regulated worldwide, and in many locations may not reflect the full cost of production, let alone indirect subsidies or negative externalities. Customers may enter into long-term pricing contracts for wind to reduce the risk of future pricing changes, thereby ensuring more stable returns for projects at the development stage. These may take the form of standard offer contracts, whereby the system operator undertakes to purchase power from wind at a fixed price for a certain period (perhaps up to a limit); these prices may be different than purchase prices from other sources, and even incorporate an implicit subsidy.
Where the price for electricity is based on market mechanisms, revenue for all producers per unit is higher when their production coincides with periods of higher prices. The profitability of wind farms will therefore be higher if their production schedule coincides with these periods. If wind represents a significant portion of supply, average revenue per unit of production may be lower as more expensive and less-efficient forms of generation, which typically set revenue levels, are displaced from economic dispatch.[citation needed] This may be of particular concern if the output of many wind plants in a market have strong temporal correlation. In economic terms, the marginal revenue of the wind sector as penetration increases may diminish.
[edit] External costs
This section does not cite any references or sources.
Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (August 2008)
Most forms of energy production create some form of negative externality: costs that are not paid by the producer or consumer of the good. For electric production, the most significant externality is pollution, which imposes social costs in increased health expenses, reduced agricultural productivity, and other problems. In addition, carbon dioxide, a greenhouse gas produced when fossil fuels are burned, may impose even greater costs in the form of global warming. Few mechanisms currently exist to internalise these costs, and the total cost is highly uncertain. Other significant externalities can include military expenditures to ensure access to fossil fuels, remediation of polluted sites, destruction of wild habitat, loss of scenery/tourism, etc.
If the external costs are taken into account, wind energy can be competitive in more cases, as costs have generally decreased because of technology development and scale enlargement. Supporters argue that, once external costs and subsidies to other forms of electrical production are accounted for, wind energy is amongst the least costly forms of electrical production. Critics argue that the level of required subsidies, the small amount of energy needs met, the expense of transmission lines to connect the wind farms to population centers, and the uncertain financial returns to wind projects make it inferior to other energy sources. Intermittency and other characteristics of wind energy also have costs that may rise with higher levels of penetration, and may change the cost-benefit ratio.
[edit] Incentives
Some of the over 6,000 wind turbines at Altamont Pass, in California, United States. Developed during a period of tax incentives in the 1980s, this wind farm has more turbines than any other in the United States.[94]Wind energy in many jurisdictions receives some financial or other support to encourage its development. Wind energy benefits from subsidies in many jurisdictions, either to increase its attractiveness, or to compensate for subsidies received by other forms of production which have significant negative externalities.
In the United States, wind power receives a tax credit for each kWh produced; at 1.9 cents per kWh in 2006, the credit has a yearly inflationary adjustment. Another tax benefit is accelerated depreciation. Many American states also provide incentives, such as exemption from property tax, mandated purchases, and additional markets for "green credits." Countries such as Canada and Germany also provide incentives for wind turbine construction, such as tax credits or minimum purchase prices for wind generation, with assured grid access (sometimes referred to as feed-in tariffs). These feed-in tariffs are typically set well above average electricity prices. The Energy Improvement and Extension Act of 2008 contains extensions of credits for wind, including microturbines.
Secondary market forces also provide incentives for businesses to use wind-generated power, even if there is a premium price for the electricity. For example, socially responsible manufacturers pay utility companies a premium that goes to subsidize and build new wind power infrastructure. Companies use wind-generated power, and in return they can claim that they are making a powerful "green" effort. In the USA the organization Green-e monitors business compliance with these renewable energy credits.[95]
[edit] Environmental effects
Main article: Environmental effects of wind power
Livestock ignore wind turbines,[96] and continue to graze as they did before wind turbines were installed.Compared to the environmental effects of traditional energy sources, the environmental effects of wind power are relatively minor. Wind power consumes no fuel, and emits no air pollution, unlike fossil fuel power sources. The energy consumed to manufacture and transport the materials used to build a wind power plant is equal to the new energy produced by the plant within a few months of operation. Garrett Gross, a scientist from UMKC in Kansas City, Missouri states, "The impact made on the environment is very little when compared to what is gained." The initial carbon dioxide emission from energy used in the installation is "paid back" within about 9 months of operation for offshore turbines.
Danger to birds and bats has been a concern in some locations. However, studies show that the number of birds killed by wind turbines is negligible compared to the number that die as a result of other human activities, and especially the environmental impacts of using non-clean power sources. Fossil fuel generation kills around twenty times as many birds per unit of energy produced than wind-farms.[97] Bat species appear to be at risk during key movement periods. Almost nothing is known about current populations of these species and the impact on bat numbers as a result of mortality at windpower locations. Offshore wind sites 10 km or more from shore do not interact with bat populations. While a wind farm may cover a large area of land, many land uses such as agriculture are compatible, with only small areas of turbine foundations and infrastructure made unavailable for use.
Aesthetics have also been an issue. In the USA, the Massachusetts Cape Wind project was delayed for years mainly because of aesthetic concerns. In the UK, repeated opinion surveys have shown that more than 70% of people either like, or do not mind, the visual impact. According to a town councillor in Ardrossan, Scotland, the overwhelming majority of locals believe that the Ardrossan Wind Farm has enhanced the area, saying that the turbines are impressive looking and bring a calming effect to the town.[98]
[edit] See also
Energy portal
Sustainable development portal
Wikimedia Commons has media related to: Wind power
Renewable energy
Distributed Energy Resources
Electricity generation
Energy development
Floating wind turbine
Green energy
Green tax shift
Grid energy storage
Intermittent energy source
List of countries by renewable electricity production
List of wind farms
List of offshore wind farms
List of wind turbine manufacturers
Merchant Wind Power
Pickens plan
Renewable energy
Vertical axis wind turbine
Wind profiler
Wind-Diesel
World energy resources and consumption
Category:Wind power by country
[edit] References
^ a b c d e f g h "World Wind Energy Report 2008" (PDF). Report. World Wind Energy Association. February 2009. http://www.wwindea.org/home/images/stories/worldwindenergyreport2008_s.pdf. Retrieved 16-March-2009.
^ a b Wind Power Increase in 2008 Exceeds 10-year Average Growth Rate
^ a b Hannele Holttinen, et al. (September 2006). ""Design and Operation of Power Systems with Large Amounts of Wind Power", IEA Wind Summary Paper" (PDF). Global Wind Power Conference September 18-21, 2006, Adelaide, Australia. http://www.ieawind.org/AnnexXXV/Meetings/Oklahoma/IEA%20SysOp%20GWPC2006%20paper_final.pdf.
^ http://www.claverton-energy.com/wind-energy-variability-new-reports.html
^ Quirky old-style contraptions make water from wind on the mesas of West Texas
^ a b Price, Trevor J (3 May 2005). "James Blyth - Britain's first modern wind power engineer". Wind Engineering 29 (3): 191–200. doi:10.1260/030952405774354921. http://www.ingentaconnect.com/content/mscp/wind/2005/00000029/00000003/art00002.
^ "Where does the wind come from and how much is there" - Claverton Energy Conference, Bath 24th Oct 2008
^ Mapping the global wind power resource
^ Lee Ranch Data 2002 Retrieved 2008-09-14
^ "Common Affordable and Renewable Electricity Supply for Europe" Claverton Energy Conference, Bath, Oct 24th 2008
^ "Sell electricity back to the utility company" Retrieved on 7 november 2008
^ The Times 22 June 2008 "Home-made energy to prop up grid" Retrieved on 7 November 2008
^ Demeo, E.A.; Grant, W.; Milligan, M.R.; Schuerger, M.J. (2005), "Wind plant integration", Power and Energy Magazine, IEEE 3 (6): 38–46, doi:10.1109/MPAE.2005.1524619, http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=1524619
^ Zavadil, R.; Miller, N.; Ellis, A.; Muljadi, E. (2005), "Making connections", Power and Energy Magazine, IEEE 3 (6): 26–37, doi:10.1109/MPAE.2005.1524618, http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=1524618
^ Wind Power: Capacity Factor, Intermittency, and what happens when the wind doesn’t blow? retrieved 24 January 2008.
^ Massachusetts Maritime Academy — Bourne, Mass This 660 kW wind turbine has a capacity factor of about 19%.
^ Wind Power in Ontario These wind farms have capacity factors of about 28–35%.
^ "The power of multiples: Connecting wind farms can make a more reliable and cheaper power source". 2007-11-21. http://www.eurekalert.org/pub_releases/2007-11/ams-tpo112107.php.
^ Archer, C. L.; Jacobson, M. Z. (2007), "Supplying Baseload Power and Reducing Transmission Requirements by Interconnecting Wind Farms", Journal of Applied Meteorology and Climatology (American Meteorological Society) 46 (11): 1701–1717, http://www.stanford.edu/group/efmh/winds/aj07_jamc.pdf
^ "Tackling Climate Change in the U.S." (PDF). American Solar Energy Society. January 2007. http://ases.org/images/stories/file/ASES/climate_change.pdf. Retrieved 2007-09-05.
^ The UK System Operator, National Grid (UK) have quoted estimates of balancing costs for 40% wind and these lie in the range £500-1000M per annum. "These balancing costs represent an additional £6 to £12 per annum on average consumer electricity bill of around £390." "National Grid's response to the House of Lords Economic Affairs Select Committee investigating the economics of renewable energy". National Grid. 2008. http://www.parliament.uk/documents/upload/EA273%20National%20Grid%20Response%20on%20Economics%20of%20Renewable%20Energy.pdf.
^ A study commissioned by the state of Minnesota considered penetration of up to 25%, and concluded that integration issues would be manageable and have incremental costs of less than one-half cent ($0.0045) per kWh.""Final Report - 2006 Minnesota Wind Integration Study"" (PDF). The Minnesota Public Utilities Commission. November 30, 2006. http://www.puc.state.mn.us/docs/windrpt_vol%201.pdf. Retrieved 2008-01-15.
^ ESB National Grid, Ireland's electric utility, in a 2004 study that, concluded that to meet the renewable energy targets set by the EU in 2001 would "increase electricity generation costs by a modest 15%" "Impact of Wind Power Generation In Ireland on the Operation of Conventional Plant and the Economic Implications" (PDF). ESB National Grid. February, 2004. pp. 36. http://www.eirgrid.com/EirGridPortal/uploads/Publications/Wind%20Impact%20Study%20-%20main%20report.pdf. Retrieved 2008-07-23.
^ Sinclair Merz Growth Scenarios for UK Renewables Generation and Implications for Future Developments and Operation of Electricity Networks BERR Publication URN 08/1021 June 2008
^ Wind power produced more than half the electricity in Spain during the early morning hours http://www.ree.es/ingles/sala_prensa/web/notas_detalle.aspx?id_nota=117
^ Mason, V.C. (December 2008). "Wind power in Denmark" (PDF). http://www.countryguardian.net/2008.%20Wind%20power%20in%20Denmark.%20%5BDecember%202008%20version%20plus%20%20Refs%5D%20(1).pdf. Retrieved 2009-08-07.
^ http://www.claverton-energy.com/is-wind-power-reliable-an-authoritative-article-from-david-millborrow-who-is-technically-experienced-and-numerate-unlike-many-other-commentators.html
^ http://www.claverton-energy.com/download/316/
^ a b Realisable Scenarios for a Future Electricity Supply based 100% on Renewable Energies Gregor Czisch, University of Kassel, Germany and Gregor Giebel, Risø National Laboratory, Technical University of Denmark
^ Effects of Large-Scale Distribution of Wind Energy in and Around Europe
^ Mitchell 2006.
^ "Geothermal Heat Pumps". Capital Electric Cooperative. http://www.capitalelec.com/Energy_Efficiency/ground_source/index.html. Retrieved 2008-10-05.
^ Wind Energy Bumps Into Power Grid’s Limits Published: August 26, 2008
^ U.S. Electric Power Industry Net Generation retrieved 12 March 2009
^ David Dixon, Nuclear Engineer (2006-08-09). "Wind Generation's Performance during the July 2006 California Heat Storm". US DOE, Oakland Operations. http://www.ecolo.org/documents/documents_in_english/Wind-heat-06-5pc.htm.
^ Graham Sinden (2005-12-01). "Characteristics of the UK wind resource: Long-term patterns and relationship to electricity demand". Environmental Change Institute, Oxford University Centre for the Environment. http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V2W-4HPD59N-1&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=bf0326d6c9fba5f5d1fc6c86b25eb2d8.
^ Wind + sun join forces at Washington power plant Retrieved 31 January 2008
^ Small Wind Systems
^ "Lake Erie Wind Resource Report, Cleveland Water Crib Monitoring Site, Two-Year Report Executive Summary" (PDF). Green Energy Ohio. 2008-01-10. http://www.development.cuyahogacounty.us/pdf_development/en-US/ExeSum_WindResrc_CleveWtrCribMntr_Reprt.pdf. Retrieved 2008-11-27. This study measured up to four times as much average wind power during winter as in summer for the test site.
^ Live data is available comparing solar and wind generation hourly since the day before yesterday, daily for last week and last month, and monthly for the last year.
^ "The Combined Power Plant: the first stage in providing 100% power from renewable energy". SolarServer. January 2008. http://www.solarserver.de/solarmagazin/anlagejanuar2008_e.html. Retrieved 2008-10-10.
^ "Why wind power works for Denmark" (PDF). Civil Engineering. May 2005. http://www.thomastelford.com/journals/DocumentLibrary/CIEN.158.2.66.pdf. Retrieved 2008-01-15.
^ Wind Energy Variability and Intermittency in the UK
^ [ http://www.claverton-energy.com/conference/programme Dr Graham Sinden, Oxford Environmental Change Institute: The implications of the Em’s 20/20/20 directive on renewable electricity generation requirements in the UK, and the potential role of offshore wind power in this context. (Graham Sinden has published a number of papers looking at the effects of integrating variable/intermittent generation into the generation mix) ]
^ http://www.awea.org/faq/basicwr.html Basic Principles of Wind Resource Evaluation, retrieved July 28, 2009
^ "Net Generation by Energy Source: Total (All Sectors)". Energy Information Administration (EIA), Dept. of Energy (DOE). September 11, 2009. http://www.eia.doe.gov/cneaf/electricity/epm/table1_1.html. Retrieved 2009-09-22.
^ "Existing Capacity by Energy Source". EIA, DOE. January 21, 2009. http://www.eia.doe.gov/cneaf/electricity/epa/epat2p2.html. Retrieved 2009-09-22.
^ a b World Wind Energy Association Statistics (PDF).
^ "Installed U.S. Wind Power Capacity Surged 45% in 2007". American Wind Energy Association. January 17, 2008. http://www.awea.org/newsroom/releases/AWEA_Market_Release_Q4_011708.html. Retrieved 2008-01-20.
^ "U.S. Wind Energy Projects". American Wind Energy Association. 2009-02-03. http://awea.org/projects. Retrieved 2009-02-03.
^ "Electric Power Monthly (January 2008 Edition)". Energy Information Administration. January 15, 2008. http://www.eia.doe.gov/cneaf/electricity/epm/epm_sum.html. Retrieved 2008-01-15.
^ "Massachusetts — 50 m Wind Power" (JPEG). U.S. National Renewable Energy Laboratory. 6 February 2007. http://www.eere.energy.gov/windandhydro/windpoweringamerica/images/windmaps/ma_50m_800.jpg. Retrieved 2008-01-15.
^ Lester R. Brown. (2008). Want a Better Way to Power Your Car? It's a Breeze. Washington Post.
^ Bradley, David (2004-02-06). "A Great Potential: The Great Lakes as a Regional Renewable Energy Source". http://greengold.org/wind/documents/107.pdf. Retrieved 2008-10-04.
^ "Great Lakes eyed for offshore wind farms". MSNBC, Associated Press. 2008-10-31. http://www.msnbc.msn.com/id/27436310/. Retrieved 2008-11-14.
^ Lema, Adrian and Kristian Ruby, ”Between fragmented authoritarianism and policy coordination: Creating a Chinese market for wind energy”, Energy Policy, Vol. 35, Issue 7, July 2007.
^ a b Watts, Jonathan (2008-07-25). "Energy in China: 'We call it the Three Gorges of the sky. The dam there taps water, we tap wind'". The Guardian. http://www.guardian.co.uk/environment/2008/jul/25/renewableenergy.alternativeenergy. Retrieved 2008-10-07.
^ "Tapping the Wind — India". February 2005. http://www.tve.org/ho/doc.cfm?aid=1678&lang=English. Retrieved 2006-10-28.
^ Watts, Himangshu (November 11 2003). "Clean Energy Brings Windfall to Indian Village". Reuters News Service. http://www.planetark.com/dailynewsstory.cfm/newsid/22758/story.htm. Retrieved 2006-10-28.
^ "Atlas do Potencial Eólico Brasileiro". http://www.cresesb.cepel.br/atlas_eolico_brasil/atlas-web.htm. Retrieved 2006-04-21.
^ "Eletrobrás — Centrais Elétricas Brasileiras S. A — Projeto Proinfa". http://www.eletrobras.gov.br/EM_Programas_Proinfa/default.asp. Retrieved 2006-04-21.
^ "Wind Energy: Rapid Growth" (PDF). Canadian Wind Energy Association. http://www.canwea.ca/downloads/en/PDFS/Rapid_growth_eng_April_06.pdf. Retrieved 2006-04-21.
^ "Canada's Current Installed Capacity" (PDF). Canadian Wind Energy Association. http://www.canwea.ca/images/uploads/File/fiche_anglais_Dec_2006.pdf. Retrieved 2006-12-11.
^ "Standard Offer Contracts Arrive In Ontario". Ontario Sustainable Energy Association. 2006. http://www.ontario-sea.org/whatsnew.html. Retrieved 2006-04-21.
^ "Call for Tenders A/O 2005-03: Wind Power 2,000 MW". Hydro-Québec. http://www.hydroquebec.com/distribution/en/marchequebecois/ao_200503/index.html. Retrieved 2006-04-21.
^ BP.com
^ 2005 月电力概况 (Chinese)
^ 2006 月电力概况 (Chinese)
^ Energy Information Administration - International Electricity Generation Data
^ International Energy Statistics
^ 深度分析产品 (Chinese)
^ 全国电力建设与投资结构继续加快调整 (Chinese)
^ Dati statistici sull’energia elettrica in Italia nel 2007 (Italian)
^ International Electricity Consumption
^ CIA - The World Factbook - Rank Order - Electricity - consumption
^ Small-scale wind energy
^ Windy Cities? New research into the urban wind resource
^ The Potential Of Small-Scale Wind Energy
^ Active filtering and load balancing with small wind energy systems
^ a b Helm, D. D. Helm and C. Hepburn (eds) (October 2009). EU climate-change policy-a critique. From: "The Economics and Politics of Climate Change". Oxford University Press. http://www.dieterhelm.co.uk/publications/SS_EU_CC_Critique.pdf. Retrieved September 6, 2009.
^ House of Lords Economic Affairs Select Committee (November 12, 2008). "Chapter 7: Recommendations and Conclusions. In: Economic Affairs – Fourth Report, Session 2007-2008. The Economics of Renewable Energy". UK Parliament website. http://www.publications.parliament.uk/pa/ld200708/ldselect/ldeconaf/195/19510.htm. Retrieved September 6, 2009.
^ BWEA report on onshore wind costs (PDF).
^ ""International Energy Outlook", 2006". Energy Information Administration. pp. 66. http://www.eia.doe.gov/oiaf/archive/ieo06/special_topics.html.
^ Helming, Troy (2004) "Uncle Sam's New Year's Resolution" ArizonaEnergy.org
^ a b Continuing boom in wind energy – 20 GW of new capacity in 2007
^ Global Wind 2005 Report
^ Wind turbine shortage continues; costs rising
^ Fact sheet 4: Tourism
^ a b BTM Forecasts 340-GW of Wind Energy by 2013
^ a b BTM Consult (2009). International Wind Energy Development World Market Update 2009
^ Archer, Cristina L.; Mark Z. Jacobson (2005). "Evaluation of global wind power". http://www.stanford.edu/group/efmh/winds/global_winds.html. Retrieved 2006-04-21.
^ http://www.claverton-energy.com/two-terawatts-average-power-output-the-uk-offshore-wind-resource.html
^ "Wind and Solar Power Systems — Design, analysis and Operation" (2nd ed., 2006), Mukund R. Patel, p. 303
^ Wind Plants of California's Altamont Pass
^ Green-e.org Retrieved on 20 May 2009
^ Buller, Erin (2008-07-11). "Capturing the wind". Uinta County Herald. http://www.uintacountyherald.com/V2_news_articles.php?heading=0&page=72&story_id=1299. Retrieved 2008-12-04. "The animals don’t care at all. We find cows and antelope napping in the shade of the turbines." - Mike Cadieux, site manager, Wyoming Wind Farm
^ Sovacool, B. K. (2009). "Contextualizing avian mortality: A preliminary appraisal of bird and bat fatalities from wind, fossil-fuel, and nuclear electricity". Energy Policy 37: 2241–2248. doi:10.1016/j.enpol.2009.02.011. edit
^ Wind farms are not only beautiful, they're absolutely necessary
[edit] External links
American Wind Energy Association (AWEA)
British Wind Energy Association (BWEA) Briefing Sheets
Canadian Wind Energy Association (CANWEA)
Chinese Wind Energy Association (CWEA)
Danish Wind Industry Association
Environmental and Energy Study Institute (EESI)
European Wind Energy Association (EWEA)
German Wind Energy Association (BWE)
Global Wind Energy Council (GWEC)
Indian Wind Energy Association (InWEA)
WindPower Television (WindpowerTV.com)
How electricity is produced using Wind Energy
Wind Power in the United States: Technology, Economic, and Policy Issues (53p), Congressional Research Service, June 2008
[edit] Wind power projects
The Red Barn Wind Project - A Community Wind Power Plant being developed in Arkansas
Jim Gordon's Nantucket Wind Energy Project
Trillium Power - Offshore Wind in The Great Lakes
Database of projects throughout the whole World
Database of offshore wind projects in North America
New York state wind projects (Wind Power Law Blog)
Wind Project Community Organizing - This free website includes dozens of current articles, links and resources about windpower, problem issues, community programs, case studies, lesson plans, etc.
Wind-powered vehicles.
Wind fuels
Inventing a super-kite to tap the energy of high-altitude wind, Feb 2009 (TED conference video), 5:25 min.
Wind energy: Pros and Cons
[hide]v • d • eWind power
Wind power Wind power · Wind turbine · Windmill · Wind-powered vehicle · History · Environmental effects
Wind turbines Airborne · Darrieus · Design · Savonius · Small · Unconventional · Vertical axis · Floating
Wind power industry Manufacturers · Consultants · Wind farm management · Software
Wind farms List of offshore wind farms · List of onshore wind farms · Community-owned
Concepts Betz' law · Capacity factor · EROEI · Grid energy storage · HVDC · Intermittency · Net energy gain · Storage · Subsidies · Wind power forecasting · Wind profile power law · Wind resource assessment
[show]v • d • eWind power by country
Overview Wind power industry · Installed wind power capacity
Regions Asia · Europe (EU)
by country Australia · Austria · Belgium · Brazil · Canada · China · Denmark · Estonia · Finland · France · Germany · Greece · India · Iran · Ireland · Italy · Japan · Morocco · Netherlands · New Zealand · Pakistan · Poland · Portugal · Romania · Russia · Spain · Sweden · Turkey · United Kingdom · United States
Portals: Energy · Sustainable development
[show]v • d • eElectricity generation
Concepts Availability factor · Baseload · Black start · Capacity factor · Demand management · EROEI · Grid storage · Intermittency · Load following · Peak demand · Spark spread
Sources Nonrenewable Coal · Fossil fuel power plant · Natural gas · Petroleum · Nuclear · Oil shale
Renewable Biomass · Geothermal · Hydro · Marine · Pumped hydro · Solar · Wind · Nuclear (Breeder)
Technology AC power · Cogeneration · Combined cycle · Cooling tower · Induction generator · Micro CHP · Microgeneration · Rankine cycle · Virtual power plant
Distribution Demand response · Distributed generation · Dynamic demand · Electricity distribution · Electrical grid · High-voltage direct current · Load control · Negawatts · Pylon · Smart grid · Super grid · TSO
Policies Carbon offset · Coal phase out · Ecotax · Energy subsidies · Feed-in Tariff · Net metering · Pigovian tax · Renewable Energy Certificates · Renewable energy payments · Renewable energy policy
Categories: Electricity distribution · Electricity economics · Power station technology · Portals: Energy · Sustainable development
[show]v • d • eApplication of wind energy
Wind power Wind turbine · Wind mill
Propulsion Sailboat · Sailing ship · Power kite · SkySails · Ice boat · Land sailing · Rotor ship
Kite applications Kite · Man-lifting kite
Air current Windcatcher
Retrieved from "http://en.wikipedia.org/wiki/Wind_power"
Categories: Wind power
Hidden categories: All articles with unsourced statements | Articles with unsourced statements from September 2009 | NPOV disputes from September 2009 | All NPOV disputes | Articles containing potentially dated statements from 2005 | All articles containing potentially dated statements | Articles with unsourced statements from October 2007 | Articles needing additional references from August 2008 | All articles needing additional references
ViewsArticle Discussion Edit this page History Personal toolsTry Beta Log in / create account Navigation
Main page
Contents
Featured content
Current events
Random article
Search
Interaction
About Wikipedia
Community portal
Recent changes
Contact Wikipedia
Donate to Wikipedia
Help
Toolbox
What links here
Related changes
Upload file
Special pages
Printable version
Permanent link
Cite this page
Languages
Afrikaans
العربية
Aragonés
Azərbaycan
Bân-lâm-gú
Беларуская
Беларуская (тарашкевіца)
Bosanski
Български
Català
Česky
Cymraeg
Dansk
Deutsch
Eesti
Ελληνικά
Español
Esperanto
Euskara
فارسی
Français
Gàidhlig
Galego
한국어
हिन्दी
Hrvatski
Bahasa Indonesia
Íslenska
Italiano
עברית
Latviešu
Lietuvių
Magyar
Nederlands
日本語
Norsk (bokmål)
Norsk (nynorsk)
Polski
Português
Română
Runa Simi
Русский
Slovenčina
Slovenščina
Српски / Srpski
Srpskohrvatski / Српскохрватски
Suomi
Svenska
தமிழ்
తెలుగు
ไทย
Türkçe
Українська
Tiếng Việt
粵語
Žemaitėška
中文
This page was last modified on 19 November 2009 at 19:38. Text is available under the Creative Commons Attribution-ShareAlike License; additional terms may apply. See Terms of Use for details.
Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization.Contact us Privacy policy About Wikipedia Disclaimers
From Wikipedia, the free encyclopedia
Jump to: navigation, search
A Wind turbine.Renewable energy
Biofuel
Biomass
Geothermal
Hydroelectricity
Solar energy
Tidal power
Wave power
Wind power
v • d • e
Wind power is the conversion of wind energy into a useful form of energy, such as electricity, using wind turbines. At the end of 2008, worldwide nameplate capacity of wind-powered generators was 121.2 gigawatts (GW).[1] In 2008, wind power produced about 1.5% of worldwide electricity usage;[1][2] and is growing rapidly, having doubled in the three years between 2005 and 2008. Several countries have achieved relatively high levels of wind power penetration, such as 19% of stationary electricity production in Denmark, 11% in Spain and Portugal, and 7% in Germany and the Republic of Ireland in 2008. As of May 2009, eighty countries around the world are using wind power on a commercial basis.[2]
Large-scale wind farms are connected to the electric power transmission network; smaller facilities are used to provide electricity to isolated locations. Utility companies increasingly buy back surplus electricity produced by small domestic turbines. Wind energy as a power source is attractive as an alternative to fossil fuels, because it is plentiful, renewable, widely distributed, clean, and produces no greenhouse gas emissions. However, the construction of wind farms is not universally welcomed because of their visual impact and other effects on the environment.
Wind power is non-dispatchable, meaning that for economic operation, all of the available output must be taken when it is available. Other resources, such as hydropower, and standard load management techniques must be used to match supply with demand. The intermittency of wind seldom creates problems when using wind power to supply a low proportion of total demand.[3][4]
Contents [hide]
1 History
2 Wind energy
2.1 Distribution of wind speed
3 Electricity generation
3.1 Grid management
3.2 Capacity factor
3.3 Penetration
3.4 Intermittency and penetration limits
3.5 Capacity credit and fuel saving
4 Turbine placement
5 Wind power usage
6 Small-scale wind power
7 Economics and feasibility
7.1 Full costs and lobbying
7.2 Relative cost of electricity by generation source
7.3 Growth and cost trends
7.4 Theoretical potential - World
7.5 Theoretical potential - UK
7.6 Direct costs
7.7 External costs
7.8 Incentives
8 Environmental effects
9 See also
10 References
11 External links
11.1 Wind power projects
[edit] History
Main article: History of wind power
Medieval depiction of a windmill
Windmills are typically installed in favourable windy locations. In the image, generators in SpainHumans have been using wind power for at least 5,500 years to propel sailboats and sailing ships, and architects have used wind-driven natural ventilation in buildings since similarly ancient times. Windmills have been used for irrigation pumping and for milling grain since the 7th century AD.
In the United States, the development of the "water-pumping windmill" was the major factor in allowing the farming and ranching of vast areas otherwise devoid of readily accessible water. Windpumps contributed to the expansion of rail transport systems throughout the world, by pumping water from water wells for the steam locomotives.[5] The multi-bladed wind turbine atop a lattice tower made of wood or steel was, for many years, a fixture of the landscape throughout rural America. When fitted with generators and battery banks, small wind machines provided electricity to isolated farms.
In July 1887, a Scottish academic, Professor James Blyth, undertook wind power experiments that culminated in a UK patent in 1891.[6] In the United States, Charles F. Brush produced electricity using a wind powered machine, starting in the winter of 1887-1888, which powered his home and laboratory until about 1900. In the 1890s, the Danish scientist and inventor Poul la Cour constructed wind turbines to generate electricity, which was then used to produce hydrogen.[6] These were the first of what was to become the modern form of wind turbine.
Small wind turbines for lighting of isolated rural buildings were widespread in the first part of the 20th century. Larger units intended for connection to a distribution network were tried at several locations including Yalta in 1931 and in Vermont in 1941.
The modern wind power industry began in 1979 with the serial production of wind turbines by Danish manufacturers Kuriant, Vestas, Nordtank, and Bonus. These early turbines were small by today's standards, with capacities of 20–30 kW each. Since then, they have increased greatly in size, while wind turbine production has expanded to many countries.
[edit] Wind energy
Further information: Wind
Distribution of wind speed (red) and energy (blue) for all of 2002 at the Lee Ranch facility in Colorado. The histogram shows measured data, while the curve is the Rayleigh model distribution for the same average wind speed. Energy is the Betz limit through a 100 m (328 ft) diameter circle facing directly into the wind. Total energy for the year through that circle was 15.4 gigawatt-hours (GWh).The Earth is unevenly heated by the sun, such that the poles receive less energy from the sun than the equator; along with this, dry land heats up (and cools down) more quickly than the seas do. The differential heating drives a global atmospheric convection system reaching from the Earth's surface to the stratosphere which acts as a virtual ceiling. Most of the energy stored in these wind movements can be found at high altitudes where continuous wind speeds of over 160 km/h (99 mph) occur. Eventually, the wind energy is converted through friction into diffuse heat throughout the Earth's surface and the atmosphere.
The total amount of economically extractable power available from the wind is considerably more than present human power use from all sources.[7] An estimated 72 TW of wind power on the Earth potentially can be commercially viable,[8] compared to about 15 TW average global power consumption from all sources in 2005. Not all the energy of the wind flowing past a given point can be recovered (see Betz' law).
[edit] Distribution of wind speed
The strength of wind varies, and an average value for a given location does not alone indicate the amount of energy a wind turbine could produce there. To assess the frequency of wind speeds at a particular location, a probability distribution function is often fit to the observed data. Different locations will have different wind speed distributions. The Weibull model closely mirrors the actual distribution of hourly wind speeds at many locations. The Weibull factor is often close to 2 and therefore a Rayleigh distribution can be used as a less accurate, but simpler model.
Because so much power is generated by higher wind speed, much of the energy comes in short bursts. The 2002 Lee Ranch sample is telling;[9] half of the energy available arrived in just 15% of the operating time. The consequence is that wind energy from a particular turbine or wind farm does not have as consistent an output as fuel-fired power plants; utilities that use wind power provide power from starting existing generation for times when the wind is weak thus wind power is primarily a fuel saver rather than a capacity saver. Making wind power more consistent requires that various existing technologies and methods be extended, in particular the use of stronger inter-regional transmission lines to link widely distributed wind farms. Problems of variability are addressed by grid energy storage, batteries, pumped-storage hydroelectricity and energy demand management.[10]
[edit] Electricity generation
Typical components of a wind turbine (gearbox, rotor shaft and brake assembly) being lifted into positionIn a wind farm, individual turbines are interconnected with a medium voltage (usually 34.5 kV) power collection system and communications network. At a substation, this medium-voltage electrical current is increased in voltage with a transformer for connection to the high voltage electric power transmission system.
The surplus power produced by domestic microgenerators can, in some jurisdictions, be fed back into the network and sold back to the utility company, producing a retail credit for the consumer to offset their energy costs.[11][12]
[edit] Grid management
Induction generators, often used for wind power projects, require reactive power for excitation so substations used in wind-power collection systems include substantial capacitor banks for power factor correction. Different types of wind turbine generators behave differently during transmission grid disturbances, so extensive modelling of the dynamic electromechanical characteristics of a new wind farm is required by transmission system operators to ensure predictable stable behaviour during system faults (see: Low voltage ride through). In particular, induction generators cannot support the system voltage during faults, unlike steam or hydro turbine-driven synchronous generators. Doubly-fed machines—wind turbines with solid-state converters between the turbine generator and the collector system—generally have more desirable properties for grid interconnection. Transmission systems operators will supply a wind farm developer with a grid code to specify the requirements for interconnection to the transmission grid. This will include power factor, constancy of frequency and dynamic behaviour of the wind farm turbines during a system fault.[13][14]
[edit] Capacity factor
Worldwide installed capacity 1997–2008, with projection 2009–13 based on an exponential fit. Data source: WWEASince wind speed is not constant, a wind farm's annual energy production is never as much as the sum of the generator nameplate ratings multiplied by the total hours in a year. The ratio of actual productivity in a year to this theoretical maximum is called the capacity factor. Typical capacity factors are 20–40%, with values at the upper end of the range in particularly favourable sites.[15] For example, a 1MW turbine with a capacity factor of 35% will not produce 8,760 MWh in a year (1 × 24 × 365), but only 1 × 0.35 × 24 × 365 = 3,066 MWh, averaging to 0.35 MW. Online data is available for some locations and the capacity factor can be calculated from the yearly output.[16][17]
Unlike fueled generating plants, the capacity factor is limited by the inherent properties of wind. Capacity factors of other types of power plant are based mostly on fuel cost, with a small amount of downtime for maintenance. Nuclear plants have low incremental fuel cost, and so are run at full output and achieve a 90% capacity factor. Plants with higher fuel cost are throttled back to follow load. Gas turbine plants using natural gas as fuel may be very expensive to operate and may be run only to meet peak power demand. A gas turbine plant may have an annual capacity factor of 5–25% due to relatively high energy production cost.
According to a 2007 Stanford University study published in the Journal of Applied Meteorology and Climatology, interconnecting ten or more wind farms can allow an average of 33% of the total energy produced to be used as reliable, baseload electric power, as long as minimum criteria are met for wind speed and turbine height.[18][19]
[edit] Penetration
Wind energy "penetration" refers to the fraction of energy produced by wind compared with the total available generation capacity. There is no generally accepted "maximum" level of wind penetration. The limit for a particular grid will depend on the existing generating plants, pricing mechanisms, capacity for storage or demand management, and other factors. An interconnected electricity grid will already include reserve generating and transmission capacity to allow for equipment failures; this reserve capacity can also serve to regulate for the varying power generation by wind plants. Studies have indicated that 20% of the total electrical energy consumption may be incorporated with minimal difficulty.[20] These studies have been for locations with geographically dispersed wind farms, some degree of dispatchable energy, or hydropower with storage capacity, demand management, and interconnection to a large grid area export of electricity when needed. Beyond this level, there are few technical limits, but the economic implications become more significant. Electrical utilities continue to study the effects of large (20% or more) scale penetration of wind generation on system stability and economics.[21][22][23][24]
At present, a few grid systems have penetration of wind energy above 5%: Denmark (values over 19%), Spain and Portugal (values over 11%), Germany and the Republic of Ireland (values over 6%). For instance, in the morning hours of 8 November 2009, wind wind power energy produced covered more than half the electricity demand in Spain during the early morning hours, setting a new record, and without problems for the network [25].
The Danish grid is heavily interconnected to the European electrical grid, and it has solved grid management problems by exporting almost half of its wind power to Norway. The correlation between electricity export and wind power production is very strong.[26]
[edit] Intermittency and penetration limits
Main article: Intermittent Power Sources
See also: Wind Power Forecasting
Diagram of the TVA pumped storage facility at Raccoon Mountain Pumped-Storage PlantElectricity generated from wind power can be highly variable at several different timescales: from hour to hour, daily, and seasonally. Annual variation also exists, but is not as significant. Related to variability is the short-term (hourly or daily) predictability of wind plant output. Like other electricity sources, wind energy must be "scheduled". Wind power forecasting methods are used, but predictability of wind plant output remains low for short-term operation.
Because instantaneous electrical generation and consumption must remain in balance to maintain grid stability, this variability can present substantial challenges to incorporating large amounts of wind power into a grid system. Intermittency and the non-dispatchable nature of wind energy production can raise costs for regulation, incremental operating reserve, and (at high penetration levels) could require an increase in the already existing energy demand management, load shedding, or storage solutions or system interconnection with HVDC cables. At low levels of wind penetration, fluctuations in load and allowance for failure of large generating units requires reserve capacity that can also regulate for variability of wind generation. Wind power can be replaced by other power stations during low wind periods. Transmission networks must already cope with outages of generation plant and daily changes in electrical demand. Systems with large wind capacity components may need more spinning reserve (plants operating at less than full load).[27][28]
A series of detailed modelling studies which looked at the Europe wide adoption of renewable energy and interlinking power grids using HVDC cables, indicates that the entire power usage could come from renewables, with 70% total energy from wind at the same sort of costs or lower than at present. Intermittency would be dealt with, according to this model, by a combination of geographic dispersion to de-link weather system effects, and the ability of HVDC to shift power from windy areas to non-windy areas.[29][30]
Pumped-storage hydroelectricity or other forms of grid energy storage can store energy developed by high-wind periods and release it when needed.[31] Stored energy increases the economic value of wind energy since it can be shifted to displace higher cost generation during peak demand periods. The potential revenue from this arbitrage can offset the cost and losses of storage; the cost of storage may add 25% to the cost of any wind energy stored, but it is not envisaged that this would apply to a large proportion of wind energy generated. Thus, the 2 GW Dinorwig pumped storage plant adds costs to nuclear energy in the UK for which it was built, but not to all the power produced from the 30 or so GW of nuclear plants in the UK.
In particular geographic regions, peak wind speeds may not coincide with peak demand for electrical power. In the US states of California and Texas, for example, hot days in summer may have low wind speed and high electrical demand due to air conditioning. Some utilities subsidize the purchase of geothermal heat pumps by their customers, to reduce electricity demand during the summer months by making air conditioning up to 70% more efficient;[32] widespread adoption of this technology would better match electricity demand to wind availability in areas with hot summers and low summer winds. Another option is to interconnect widely dispersed geographic areas with an HVDC "Super grid". In the USA it is estimated that to upgrade the transmission system to take in planned or potential renewables would cost at least $60 billion[33]. Total annual US power consumption in 2006 was 4 thousand billion kWh.[34] Over an asset life of 40 years and low cost utility investment grade funding, the cost of $60 billion investment would be about 5% p.a. (i.e. $3 billion p.a.) Dividing by total power used gives an increased unit cost of around $3,000,000,000 × 100 / 4,000 × 1 exp9 = 0.075 cent/kWh.
In the UK, demand for electricity is higher in winter than in summer, and so are wind speeds.[35][36] Solar power tends to be complementary to wind.[37][38] On daily to weekly timescales, high pressure areas tend to bring clear skies and low surface winds, whereas low pressure areas tend to be windier and cloudier. On seasonal timescales, solar energy typically peaks in summer, whereas in many areas wind energy is lower in summer and higher in winter.[39] Thus the intermittencies of wind and solar power tend to cancel each other somewhat. A demonstration project at the Massachusetts Maritime Academy shows the effect.[40] The Institute for Solar Energy Supply Technology of the University of Kassel pilot-tested a combined power plant linking solar, wind, biogas and hydrostorage to provide load-following power around the clock, entirely from renewable sources.[41]
A report from Denmark noted that their wind power network was without power for 54 days during 2002.[42] Wind power advocates argue that these periods of low wind can be dealt with by simply restarting existing power stations that have been held in readiness or interlinking with HVDC.[29]
Three reports on the wind variability in the UK issued in 2009, generally agree that variability of wind needs to be taken into account, but it does not make the grid unmanageable; and the additional costs, which are modest, can be quantified.[43]
A 2006 International Energy Agency forum presented costs for managing intermittency as a function of wind-energy's share of total capacity for several countries, as shown:
Increase in system operation costs, Euros per MWH, for 10% and 20% wind share[3]
10% 20%
Germany 2.5 3.2
Denmark 0.4 0.8
Finland 0.3 1.5
Norway 0.1 0.3
Sweden 0.3 0.7
[edit] Capacity credit and fuel saving
Many commentators concentrate on whether or not wind has any "capacity credit" without defining what they mean by this and its relevance. Wind does have a capacity credit, using a widely accepted and meaningful definition, equal to about 20% of its rated output (but this figure varies depending on actual circumstances). This means that reserve capacity on a system equal in MW to 20% of added wind could be retired when such wind is added without affecting system security or robustness. But the precise value is irrelevant since the main value of wind, (in the UK, worth 5 times the capacity credit value[44]) is its fuel and CO2 savings.
[edit] Turbine placement
Main article: Wind farm
See also: Wind atlas
Good selection of a wind turbine site is critical to economic development of wind power. Aside from the availability of wind itself, other factors include the availability of transmission lines, value of energy to be produced, cost of land acquisition, land use considerations, and environmental impact of construction and operations. Off-shore locations may offset their higher construction cost with higher annual load factors, thereby reducing cost of energy produced. Wind farm designers use specialized wind energy software applications to evaluate the impact of these issues on a given wind farm design.[citation needed]
Wind power density (WPD) is a calculation of the effective power of the wind at a particular location.[45] A map showing the distribution of wind power density is a first step in identifying possible locations for wind turbines. In the United States, the National Renewable Energy Laboratory classifies wind power density into ascending classes. The larger the WPD at a location, the higher it is rated by class. Wind power classes 3 (300–400 W/m2 at 50 m altitude) to 7 (800–2000 W/m2 at 50 m altitude) are generally considered suitable for wind power development. There are 625,000 km2 in the contiguous United States that have class 3 or higher wind resources and which are within 10 km of electric transmission lines. If this area is fully utilized for wind power, it would produce power at the average continuous equivalent rate of 734 GWe. For comparison, in 2007 the US consumed electricity at an average rate of 474 GW,[46] from a total generating capacity of 1,088 GW.[47]
[edit] Wind power usage
Further information: Category:Wind power by country and Installed wind power capacity
Installed windpower capacity (MW)[1] # Nation 2005 2006 2007 2008
- European Union 40,722 48,122 56,614 65,255
1 United States 9,149 11,603 16,819 25,170
2 Germany 18,428 20,622 22,247 23,903
3 Spain 10,028 11,630 15,145 16,740
4 China 1,266 2,599 5,912 12,210
5 India 4,430 6,270 7,850 9,587
6 Italy 1,718 2,123 2,726 3,537
7 France 779 1,589 2,477 3,426
8 United Kingdom 1,353 1,963 2,389 3,288
9 Denmark 3,132 3,140 3,129 3,164
10 Portugal 1,022 1,716 2,130 2,862
11 Canada 683 1,460 1,846 2,369
12 Netherlands 1,236 1,571 1,759 2,237
13 Japan 1,040 1,309 1,528 1,880
14 Australia 579 817 817 1,494
15 Ireland 495 746 805 1,245
16 Sweden 509 571 831 1,067
17 Austria 819 965 982 995
18 Greece 573 758 873 990
19 Poland 83 153 276 472
20 Turkey 20 65 207 433
21 Norway 268 325 333 428
22 Egypt 145 230 310 390
23 Belgium 167 194 287 384
24 Taiwan 104 188 280 358
25 Brazil 29 237 247 339
26 New Zealand 168 171 322 325
27 South Korea 119 176 192 278
28 Bulgaria 14 36 57 158
29 Czech Republic 30 57 116 150
30 Finland 82 86 110 140
31 Hungary 18 61 65 127
32 Morocco 64 64 125 125
33 Ukraine 77 86 89 90
34 Mexico 2 84 85 85
35 Iran 32 47 67 82
Rest of Europe 141 204 233 261
Rest of Americas 155 159 184 210
Rest of Africa
& Middle East 52 52 51 56
Rest of Asia
& Oceania 27 27 27 36
World total (MW) 59,024 74,151 93,927 121,188
There are now many thousands of wind turbines operating, with a total nameplate capacity of 121,188 MWp of which wind power in Europe accounts for 55% (2008). World wind generation capacity more than quadrupled between 2000 and 2006, doubling about every three years. 81% of wind power installations are in the US and Europe. The share of the top five countries in terms of new installations fell from 71% in 2004 to 62% in 2006, but climbed to 73% by 2008 as those countries—the United States, Germany, Spain, China, and India—have seen substantial capacity growth in the past two years (see chart).
By 2010, the World Wind Energy Association expects 160GW of capacity to be installed worldwide,[48] up from 73.9 GW at the end of 2006, implying an anticipated net growth rate of more than 21% per year.
Denmark generates nearly one-fifth of its electricity with wind turbines—the highest percentage of any country—and is ninth in the world in total wind power generation. Denmark is prominent in the manufacturing and use of wind turbines, with a commitment made in the 1970s to eventually produce half of the country's power by wind.
In recent years, the US has added more wind energy to its grid than any other country, with a growth in power capacity of 45% to 16.8 GW in 2007[49] and surpassing Germany's nameplate capacity in 2008. California was one of the incubators of the modern wind power industry, and led the U.S. in installed capacity for many years; however, by the end of 2006, Texas became the leading wind power state and continues to extend its lead. At the end of 2008, the state had 7,116 MW installed, which would have ranked it sixth in the world if Texas was a separate country. Iowa and Minnesota each grew to more than 1 GW installed by the end of 2007; in 2008 they were joined by Oregon, Washington, and Colorado.[50] Wind power generation in the U.S. was up 31.8% in February, 2007 from February, 2006.[51] The average output of one MW of wind power is equivalent to the average electricity consumption of about 250 American households. According to the American Wind Energy Association, wind will generate enough electricity in 2008 to power just over 1% (equivalent to 4.5 million households) of total electricity in U.S., up from less than 0.1% in 1999. U.S. Department of Energy studies have concluded wind harvested in the Great Plains states of Texas, Kansas, and North Dakota could provide enough electricity to power the entire nation, and that offshore wind farms could do the same job.[52][53] In addition, the wind resource over and around the Great Lakes, recoverable with currently available technology, could by itself provide 80% as much power as the U.S. and Canada currently generate from non-renewable resources,[54] with Michigan's share alone equating to one third of current U.S. electricity demand.[55]
In 2005, China announced it would build a 1000 MW wind farm in Hebei for completion in 2020. China has set a generating target of 30,000 MW by 2020 from renewable energy sources — it says indigenous wind power could generate up to 253,000 MW.[56] A Chinese renewable energy law was adopted in November 2004, following the World Wind Energy Conference organized by the Chinese and the World Wind Energy Association. By 2008, wind power was growing faster in China than the government had planned, and indeed faster in percentage terms than in any other large country, having more than doubled each year since 2005. Policymakers doubled their wind power prediction for 2010, after the wind industry reached the original goal of 5 GW three years ahead of schedule.[57] Current trends suggest an actual installed capacity near 20 GW by 2010, with China shortly thereafter pursuing the United States for the world wind power lead.[57]
India ranks 5th in the world with a total wind power capacity of 9,587 MW in 2008,[1] or 3% of all electricity produced in India. The World Wind Energy Conference in New Delhi in November 2006 has given additional impetus to the Indian wind industry.[48] Muppandal village in Tamil Nadu state, India, has several wind turbine farms in its vicinity, and is one of the major wind energy harnessing centres in India led by majors like Suzlon, Vestas, Micon among others.[58][59]
Mexico recently opened La Venta II wind power project as an important step in reducing Mexico's consumption of fossil fuels. The 88 MW project is the first of its kind in Mexico, and will provide 13 percent of the electricity needs of the state of Oaxaca. By 2012 the project will have a capacity of 3500 MW.
Another growing market is Brazil, with a wind potential of 143 GW.[60] The federal government has created an incentive program, called Proinfa,[61] to build production capacity of 3300 MW of renewable energy for 2008, of which 1422 MW through wind energy. The program seeks to produce 10% of Brazilian electricity through renewable sources.
South Africa has a proposed station situated on the West Coast north of the Olifants River mouth near the town of Koekenaap, east of Vredendal in the Western Cape province. The station is proposed to have a total output of 100MW although there are negotiations to double this capacity. The plant could be operational by 2010.
France has announced a target of 12,500 MW installed by 2010, though their installation trends over the past few years suggest they'll fall well short of their goal.
Canada experienced rapid growth of wind capacity between 2000 and 2006, with total installed capacity increasing from 137 MW to 1,451 MW, and showing an annual growth rate of 38%.[62] Particularly rapid growth was seen in 2006, with total capacity doubling from the 684 MW at end-2005.[63] This growth was fed by measures including installation targets, economic incentives and political support. For example, the Ontario government announced that it will introduce a feed-in tariff for wind power, referred to as 'Standard Offer Contracts', which may boost the wind industry across the province.[64] In Quebec, the provincially owned electric utility plans to purchase an additional 2000 MW by 2013.[65]
Annual Wind Power Generation (TWh) and total electricity consumption(TWh) for 10 largest countries[1][66][67][68][69][70] Rank Nation 2005 2006 2007 2008
Wind
Power Capacity
Factor % Total
Power Wind
Power Capacity
Factor % Total
Power Wind
Power Capacity
Factor % Total
Power Wind
Power Capacity
Factor % Total
Power
1 United States 17.8 22.2% 0.4% 4048.9 26.6 26.1% 0.7% 4058.1 34.5 23.4% 0.8% 4149.9 52.0 23.5% 1.3% 4108.6
2 Germany 27.2 16.9% 5.1% 533.7 30.7 17.0% 5.4% 569.9 38.5 19.7% 6.6% 584.9
3 Spain 20.7 23.5% 7.9% 260.7 22.9 22.4% 8.5% 268.8 27.2 20.5% 9.8% 276.8 31.4 21.7% 11.1% 282.1
4 China 1.9 17.2% 0.1% 2474.7 3.7 16.2% 0.1% 2834.4 5.6 [71] 10.6% 0.2% 3255.9 12.8 [72] 12.0% 0.4% 3426.8
5 India 6.3 16.2% 0.9% 679.2 7.6 13.8% 1.0% 726.7 14.7 21.0% 1.9% 774.7
6 Italy 2.3 15.3% 0.7% 330.4 3.0 16.1% 0.9% 337.5 4.0[73] 16.7% 1.2% 339.9 4.9 15.7% 1.4% 339.5
7 France 0.9 13.6% 0.2% 482.4 2.2 16.0% 0.5% 478.4 4.0 18.6% 0.8% 480.3 5.6 18.8% 1.1% 494.5
8 United Kingdom 2.8 24.0% 0.7% 407.4 4.0 23.2% 1.0% 383.9 5.9 28.2% 1.5% 379.8
9 Denmark 6.6 24.0% 18.5% 35.7 6.1 22.2% 16.8% 36.4 7.2 26.3% 19.7% 36.4 6.9 24.9% 19.1% 36.2
10 Portugal 1.7 19.0% 3.6% 47.9 2.9 19.3% 5.9% 49.2 4.0 21.2% 8.0% 50.1 5.7 22.7% 11.3% 50.6
World total (TWh) 99.5 19.2% 0.6% 15,746.5[74] 124.9 19.2% 0.7% 16,790 17,480[75] 260[1] 24.5%[1] 1.5%[1]
[edit] Small-scale wind power
Further information: Microgeneration
This wind turbine charges a 12 V battery to run 12 V appliances.Small-scale wind power is the name given to wind generation systems with the capacity to produce up to 50 kW of electrical power.[76] Isolated communities, that may otherwise rely on diesel generators may use wind turbines to displace diesel fuel consumption. Individuals may purchase these systems to reduce or eliminate their dependence on grid electricity for economic or other reasons, or to reduce their carbon footprint. Wind turbines have been used for household electricity generation in conjunction with battery storage over many decades in remote areas.
5 Kilowatt Vertical Axis Wind TurbineGrid-connected wind turbines may use grid energy storage, displacing purchased energy with local production when available. Off-grid system users can either adapt to intermittent power or use batteries, photovoltaic or diesel systems to supplement the wind turbine. In urban locations, where it is difficult to obtain predictable or large amounts of wind energy (little is known about the actual wind resource of towns and cities [77]), smaller systems may still be used to run low-power equipment. Equipment such as parking meters or wireless Internet gateways may be powered by a wind turbine that charges a small battery, replacing the need for a connection to the power grid.
A new Carbon Trust study into the potential of small-scale wind energy has found that small wind turbines could provide up to 1.5 terawatt hours (TW·h) per year of electricity (0.4% of total UK electricity consumption), saving 0.6 million tonnes of carbon dioxide (Mt CO2) emission savings. This is based on the assumption that 10% of households would install turbines at costs competitive with grid electricity, around 12 pence (US 19 cents) a kWh.[78]
Distributed generation from renewable resources is increasing as a consequence of the increased awareness of climate change. The electronic interfaces required to connect renewable generation units with the utility system can include additional functions, such as the active filtering to enhance the power quality.[79]
[edit] Economics and feasibility
The neutrality of this section is disputed. Please see the discussion on the talk page. Please do not remove this message until the dispute is resolved. (September 2009)
Erection of an Enercon E70-4[edit] Full costs and lobbying
Commenting on the EU's 2020 renewable energy target, Helm (2009) is critical of how the costs of wind power are citied by lobbyists:[80]
For those with an economic interest in capturing as much of the climate-change pork barrel as possible, there are two ways of presenting the costs [of wind power] in a favourable light: first, define the cost base as narrowly as possible; and, second, assume that the costs will fall over time with R&D and large-scale deployment. And, for good measure, when considering the alternatives, go for a wider cost base (for example, focusing on the full fuel-cycle costs of nuclear and coal-mining for coal generation) and assume that these technologies are mature, and even that costs might rise (for example, invoking the highly questionable ‘peak oil hypothesis’).
A House of Lords Select Committee report (2008) on renewable energy in the UK says:[81]
We have a particular concern over the prospective role of wind generated and other intermittent sources of electricity in the UK, in the absence of a break-through in electricity storage technology or the integration of the UK grid with that of continental Europe. Wind generation offers the most readily available short-term enhancement in renewable electricity and its base cost is relatively cheap. Yet the evidence presented to us implies that the full costs of wind generation (allowing for intermittency, back-up conventional plant and grid connection), although declining over time, remain significantly higher than those of conventional or nuclear generation (even before allowing for support costs and the environmental impacts of wind farms). Furthermore, the evidence suggests that the capacity credit of wind power (its probable power output at the time of need) is very low; so it cannot be relied upon to meet peak demand. Thus wind generation needs to be viewed largely as additional capacity to that which will need to be provided, in any event, by more reliable means
Helm (2009) says that wind's problem of intermittent supply will probably lead to another dash-for-gas or dash-for-coal in Europe, possibly with a negative impact on energy security.[80]
[edit] Relative cost of electricity by generation source
See Relative cost of electricity generated by different sources
[edit] Growth and cost trends
Wind and hydroelectric power generation have negligible fuel costs and relatively low maintenance costs. Wind power has a low marginal cost and a high proportion of capital cost. The estimated average cost per unit incorporates the cost of construction of the turbine and transmission facilities, borrowed funds, return to investors (including cost of risk), estimated annual production, and other components, averaged over the projected useful life of the equipment, which may be in excess of twenty years. Energy cost estimates are highly dependent on these assumptions so published cost figures can differ substantially. A British Wind Energy Association report gives an average generation cost of onshore wind power of around 3.2 pence (between US 5 and 6 cents) per kWh (2005).[82] Cost per unit of energy produced was estimated in 2006 to be comparable to the cost of new generating capacity in the US for coal and natural gas: wind cost was estimated at $55.80 per MWh, coal at $53.10/MWh and natural gas at $52.50.[83] Other sources in various studies have estimated wind to be more expensive than other sources (see Economics of new nuclear power plants, Clean coal, and Carbon capture and storage).
In 2004, wind energy cost a fifth of what it did in the 1980s, and some expected that downward trend to continue as larger multi-megawatt turbines were mass-produced.[84] However, installed cost averaged €1,300 a kW in 2007,[85] compared to €1,100 a kW in 2005.[86] Not as many facilities can produce large modern turbines and their towers and foundations, so constraints develop in the supply of turbines resulting in higher costs.[87] Research from a wide variety of sources in various countries shows that support for wind power is consistently 70–80% among the general public.[88]
Global Wind Energy Council (GWEC) figures show that 2007 recorded an increase of installed capacity of 20 GW, taking the total installed wind energy capacity to 94 GW, up from 74 GW in 2006. Despite constraints facing supply chains for wind turbines, the annual market for wind continued to increase at an estimated rate of 37%, following 32% growth in 2006. In terms of economic value, the wind energy sector has become one of the important players in the energy markets, with the total value of new generating equipment installed in 2007 reaching €25 billion, or US$36 billion.[85]
Although the wind power industry will be impacted by the global financial crisis in 2009 and 2010, a BTM Consult five year forecast up to 2013 projects substantial growth. Over the past five years the average growth in new installations has been 27.6 percent each year. In the forecast to 2013 the expected average annual growth rate is 15.7 percent.[89][90] More than 200 GW of new wind power capacity could come on line before the end of 2013. Wind power market penetration is expected to reach 3.35 percent by 2013 and 8 percent by 2018.[89][90]
Existing generation capacity represents sunk costs, and the decision to continue production will depend on marginal costs going forward, not estimated average costs at project inception. For example, the estimated cost of new wind power capacity may be lower than that for "new coal" (estimated average costs for new generation capacity) but higher than for "old coal" (marginal cost of production for existing capacity). Therefore, the choice to increase wind capacity will depend on factors including the profile of existing generation capacity.
[edit] Theoretical potential - World
Map of available wind power for the United States. Color codes indicate wind power density class.Wind power available in the atmosphere is much greater than current world energy consumption. The most comprehensive study As of 2005[update][91] found the potential of wind power on land and near-shore to be 72 TW, equivalent to 54,000 MToE (million tons of oil equivalent) per year, or over five times the world's current energy use in all forms. The potential takes into account only locations with mean annual wind speeds ≥ 6.9 m/s at 80 m. The study assumes six 1.5 megawatt, 77 m diameter turbines per square kilometer on roughly 13% of the total global land area (though that land would also be available for other compatible uses such as farming). The authors acknowledge that many practical barriers would need to be overcome to reach this theoretical capacity.
The practical limit to exploitation of wind power will be set by economic and environmental factors, since the resource available is far larger than any practical means to develop it.
[edit] Theoretical potential - UK
A recent estimate gives the total potential average output for UK for various depth and distance from the coast. The maximum case considered was beyond 200 km from shore and in depths of 100 - 700 m necessitating floating wind turbines) and this gave an average resource of 2,000 GWe which is to be compared with the average UK demand of about 40 GWe.[92]
[edit] Direct costs
Many potential sites for wind farms are far from demand centres, requiring substantially more money to construct new transmission lines and substations. In some regions this is partly because frequent strong winds themselves have discouraged dense human settlement in especially windy areas. The wind which was historically a nuisance is now becoming a valuable resource, but it may be far from large populations which developed in areas more sheltered from wind.
Since the primary cost of producing wind energy is construction and there are no fuel costs, the average cost of wind energy per unit of production depends on a few key assumptions, such as the cost of capital and years of assumed service. The marginal cost of wind energy once a plant is constructed is usually less than 1 cent per kWh.[93] Since the cost of capital plays a large part in projected cost, risk (as perceived by investors) will affect projected costs per unit of electricity.
The commercial viability of wind power also depends on the price paid to power producers. Electricity prices are highly regulated worldwide, and in many locations may not reflect the full cost of production, let alone indirect subsidies or negative externalities. Customers may enter into long-term pricing contracts for wind to reduce the risk of future pricing changes, thereby ensuring more stable returns for projects at the development stage. These may take the form of standard offer contracts, whereby the system operator undertakes to purchase power from wind at a fixed price for a certain period (perhaps up to a limit); these prices may be different than purchase prices from other sources, and even incorporate an implicit subsidy.
Where the price for electricity is based on market mechanisms, revenue for all producers per unit is higher when their production coincides with periods of higher prices. The profitability of wind farms will therefore be higher if their production schedule coincides with these periods. If wind represents a significant portion of supply, average revenue per unit of production may be lower as more expensive and less-efficient forms of generation, which typically set revenue levels, are displaced from economic dispatch.[citation needed] This may be of particular concern if the output of many wind plants in a market have strong temporal correlation. In economic terms, the marginal revenue of the wind sector as penetration increases may diminish.
[edit] External costs
This section does not cite any references or sources.
Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (August 2008)
Most forms of energy production create some form of negative externality: costs that are not paid by the producer or consumer of the good. For electric production, the most significant externality is pollution, which imposes social costs in increased health expenses, reduced agricultural productivity, and other problems. In addition, carbon dioxide, a greenhouse gas produced when fossil fuels are burned, may impose even greater costs in the form of global warming. Few mechanisms currently exist to internalise these costs, and the total cost is highly uncertain. Other significant externalities can include military expenditures to ensure access to fossil fuels, remediation of polluted sites, destruction of wild habitat, loss of scenery/tourism, etc.
If the external costs are taken into account, wind energy can be competitive in more cases, as costs have generally decreased because of technology development and scale enlargement. Supporters argue that, once external costs and subsidies to other forms of electrical production are accounted for, wind energy is amongst the least costly forms of electrical production. Critics argue that the level of required subsidies, the small amount of energy needs met, the expense of transmission lines to connect the wind farms to population centers, and the uncertain financial returns to wind projects make it inferior to other energy sources. Intermittency and other characteristics of wind energy also have costs that may rise with higher levels of penetration, and may change the cost-benefit ratio.
[edit] Incentives
Some of the over 6,000 wind turbines at Altamont Pass, in California, United States. Developed during a period of tax incentives in the 1980s, this wind farm has more turbines than any other in the United States.[94]Wind energy in many jurisdictions receives some financial or other support to encourage its development. Wind energy benefits from subsidies in many jurisdictions, either to increase its attractiveness, or to compensate for subsidies received by other forms of production which have significant negative externalities.
In the United States, wind power receives a tax credit for each kWh produced; at 1.9 cents per kWh in 2006, the credit has a yearly inflationary adjustment. Another tax benefit is accelerated depreciation. Many American states also provide incentives, such as exemption from property tax, mandated purchases, and additional markets for "green credits." Countries such as Canada and Germany also provide incentives for wind turbine construction, such as tax credits or minimum purchase prices for wind generation, with assured grid access (sometimes referred to as feed-in tariffs). These feed-in tariffs are typically set well above average electricity prices. The Energy Improvement and Extension Act of 2008 contains extensions of credits for wind, including microturbines.
Secondary market forces also provide incentives for businesses to use wind-generated power, even if there is a premium price for the electricity. For example, socially responsible manufacturers pay utility companies a premium that goes to subsidize and build new wind power infrastructure. Companies use wind-generated power, and in return they can claim that they are making a powerful "green" effort. In the USA the organization Green-e monitors business compliance with these renewable energy credits.[95]
[edit] Environmental effects
Main article: Environmental effects of wind power
Livestock ignore wind turbines,[96] and continue to graze as they did before wind turbines were installed.Compared to the environmental effects of traditional energy sources, the environmental effects of wind power are relatively minor. Wind power consumes no fuel, and emits no air pollution, unlike fossil fuel power sources. The energy consumed to manufacture and transport the materials used to build a wind power plant is equal to the new energy produced by the plant within a few months of operation. Garrett Gross, a scientist from UMKC in Kansas City, Missouri states, "The impact made on the environment is very little when compared to what is gained." The initial carbon dioxide emission from energy used in the installation is "paid back" within about 9 months of operation for offshore turbines.
Danger to birds and bats has been a concern in some locations. However, studies show that the number of birds killed by wind turbines is negligible compared to the number that die as a result of other human activities, and especially the environmental impacts of using non-clean power sources. Fossil fuel generation kills around twenty times as many birds per unit of energy produced than wind-farms.[97] Bat species appear to be at risk during key movement periods. Almost nothing is known about current populations of these species and the impact on bat numbers as a result of mortality at windpower locations. Offshore wind sites 10 km or more from shore do not interact with bat populations. While a wind farm may cover a large area of land, many land uses such as agriculture are compatible, with only small areas of turbine foundations and infrastructure made unavailable for use.
Aesthetics have also been an issue. In the USA, the Massachusetts Cape Wind project was delayed for years mainly because of aesthetic concerns. In the UK, repeated opinion surveys have shown that more than 70% of people either like, or do not mind, the visual impact. According to a town councillor in Ardrossan, Scotland, the overwhelming majority of locals believe that the Ardrossan Wind Farm has enhanced the area, saying that the turbines are impressive looking and bring a calming effect to the town.[98]
[edit] See also
Energy portal
Sustainable development portal
Wikimedia Commons has media related to: Wind power
Renewable energy
Distributed Energy Resources
Electricity generation
Energy development
Floating wind turbine
Green energy
Green tax shift
Grid energy storage
Intermittent energy source
List of countries by renewable electricity production
List of wind farms
List of offshore wind farms
List of wind turbine manufacturers
Merchant Wind Power
Pickens plan
Renewable energy
Vertical axis wind turbine
Wind profiler
Wind-Diesel
World energy resources and consumption
Category:Wind power by country
[edit] References
^ a b c d e f g h "World Wind Energy Report 2008" (PDF). Report. World Wind Energy Association. February 2009. http://www.wwindea.org/home/images/stories/worldwindenergyreport2008_s.pdf. Retrieved 16-March-2009.
^ a b Wind Power Increase in 2008 Exceeds 10-year Average Growth Rate
^ a b Hannele Holttinen, et al. (September 2006). ""Design and Operation of Power Systems with Large Amounts of Wind Power", IEA Wind Summary Paper" (PDF). Global Wind Power Conference September 18-21, 2006, Adelaide, Australia. http://www.ieawind.org/AnnexXXV/Meetings/Oklahoma/IEA%20SysOp%20GWPC2006%20paper_final.pdf.
^ http://www.claverton-energy.com/wind-energy-variability-new-reports.html
^ Quirky old-style contraptions make water from wind on the mesas of West Texas
^ a b Price, Trevor J (3 May 2005). "James Blyth - Britain's first modern wind power engineer". Wind Engineering 29 (3): 191–200. doi:10.1260/030952405774354921. http://www.ingentaconnect.com/content/mscp/wind/2005/00000029/00000003/art00002.
^ "Where does the wind come from and how much is there" - Claverton Energy Conference, Bath 24th Oct 2008
^ Mapping the global wind power resource
^ Lee Ranch Data 2002 Retrieved 2008-09-14
^ "Common Affordable and Renewable Electricity Supply for Europe" Claverton Energy Conference, Bath, Oct 24th 2008
^ "Sell electricity back to the utility company" Retrieved on 7 november 2008
^ The Times 22 June 2008 "Home-made energy to prop up grid" Retrieved on 7 November 2008
^ Demeo, E.A.; Grant, W.; Milligan, M.R.; Schuerger, M.J. (2005), "Wind plant integration", Power and Energy Magazine, IEEE 3 (6): 38–46, doi:10.1109/MPAE.2005.1524619, http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=1524619
^ Zavadil, R.; Miller, N.; Ellis, A.; Muljadi, E. (2005), "Making connections", Power and Energy Magazine, IEEE 3 (6): 26–37, doi:10.1109/MPAE.2005.1524618, http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=1524618
^ Wind Power: Capacity Factor, Intermittency, and what happens when the wind doesn’t blow? retrieved 24 January 2008.
^ Massachusetts Maritime Academy — Bourne, Mass This 660 kW wind turbine has a capacity factor of about 19%.
^ Wind Power in Ontario These wind farms have capacity factors of about 28–35%.
^ "The power of multiples: Connecting wind farms can make a more reliable and cheaper power source". 2007-11-21. http://www.eurekalert.org/pub_releases/2007-11/ams-tpo112107.php.
^ Archer, C. L.; Jacobson, M. Z. (2007), "Supplying Baseload Power and Reducing Transmission Requirements by Interconnecting Wind Farms", Journal of Applied Meteorology and Climatology (American Meteorological Society) 46 (11): 1701–1717, http://www.stanford.edu/group/efmh/winds/aj07_jamc.pdf
^ "Tackling Climate Change in the U.S." (PDF). American Solar Energy Society. January 2007. http://ases.org/images/stories/file/ASES/climate_change.pdf. Retrieved 2007-09-05.
^ The UK System Operator, National Grid (UK) have quoted estimates of balancing costs for 40% wind and these lie in the range £500-1000M per annum. "These balancing costs represent an additional £6 to £12 per annum on average consumer electricity bill of around £390." "National Grid's response to the House of Lords Economic Affairs Select Committee investigating the economics of renewable energy". National Grid. 2008. http://www.parliament.uk/documents/upload/EA273%20National%20Grid%20Response%20on%20Economics%20of%20Renewable%20Energy.pdf.
^ A study commissioned by the state of Minnesota considered penetration of up to 25%, and concluded that integration issues would be manageable and have incremental costs of less than one-half cent ($0.0045) per kWh.""Final Report - 2006 Minnesota Wind Integration Study"" (PDF). The Minnesota Public Utilities Commission. November 30, 2006. http://www.puc.state.mn.us/docs/windrpt_vol%201.pdf. Retrieved 2008-01-15.
^ ESB National Grid, Ireland's electric utility, in a 2004 study that, concluded that to meet the renewable energy targets set by the EU in 2001 would "increase electricity generation costs by a modest 15%" "Impact of Wind Power Generation In Ireland on the Operation of Conventional Plant and the Economic Implications" (PDF). ESB National Grid. February, 2004. pp. 36. http://www.eirgrid.com/EirGridPortal/uploads/Publications/Wind%20Impact%20Study%20-%20main%20report.pdf. Retrieved 2008-07-23.
^ Sinclair Merz Growth Scenarios for UK Renewables Generation and Implications for Future Developments and Operation of Electricity Networks BERR Publication URN 08/1021 June 2008
^ Wind power produced more than half the electricity in Spain during the early morning hours http://www.ree.es/ingles/sala_prensa/web/notas_detalle.aspx?id_nota=117
^ Mason, V.C. (December 2008). "Wind power in Denmark" (PDF). http://www.countryguardian.net/2008.%20Wind%20power%20in%20Denmark.%20%5BDecember%202008%20version%20plus%20%20Refs%5D%20(1).pdf. Retrieved 2009-08-07.
^ http://www.claverton-energy.com/is-wind-power-reliable-an-authoritative-article-from-david-millborrow-who-is-technically-experienced-and-numerate-unlike-many-other-commentators.html
^ http://www.claverton-energy.com/download/316/
^ a b Realisable Scenarios for a Future Electricity Supply based 100% on Renewable Energies Gregor Czisch, University of Kassel, Germany and Gregor Giebel, Risø National Laboratory, Technical University of Denmark
^ Effects of Large-Scale Distribution of Wind Energy in and Around Europe
^ Mitchell 2006.
^ "Geothermal Heat Pumps". Capital Electric Cooperative. http://www.capitalelec.com/Energy_Efficiency/ground_source/index.html. Retrieved 2008-10-05.
^ Wind Energy Bumps Into Power Grid’s Limits Published: August 26, 2008
^ U.S. Electric Power Industry Net Generation retrieved 12 March 2009
^ David Dixon, Nuclear Engineer (2006-08-09). "Wind Generation's Performance during the July 2006 California Heat Storm". US DOE, Oakland Operations. http://www.ecolo.org/documents/documents_in_english/Wind-heat-06-5pc.htm.
^ Graham Sinden (2005-12-01). "Characteristics of the UK wind resource: Long-term patterns and relationship to electricity demand". Environmental Change Institute, Oxford University Centre for the Environment. http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V2W-4HPD59N-1&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=bf0326d6c9fba5f5d1fc6c86b25eb2d8.
^ Wind + sun join forces at Washington power plant Retrieved 31 January 2008
^ Small Wind Systems
^ "Lake Erie Wind Resource Report, Cleveland Water Crib Monitoring Site, Two-Year Report Executive Summary" (PDF). Green Energy Ohio. 2008-01-10. http://www.development.cuyahogacounty.us/pdf_development/en-US/ExeSum_WindResrc_CleveWtrCribMntr_Reprt.pdf. Retrieved 2008-11-27. This study measured up to four times as much average wind power during winter as in summer for the test site.
^ Live data is available comparing solar and wind generation hourly since the day before yesterday, daily for last week and last month, and monthly for the last year.
^ "The Combined Power Plant: the first stage in providing 100% power from renewable energy". SolarServer. January 2008. http://www.solarserver.de/solarmagazin/anlagejanuar2008_e.html. Retrieved 2008-10-10.
^ "Why wind power works for Denmark" (PDF). Civil Engineering. May 2005. http://www.thomastelford.com/journals/DocumentLibrary/CIEN.158.2.66.pdf. Retrieved 2008-01-15.
^ Wind Energy Variability and Intermittency in the UK
^ [ http://www.claverton-energy.com/conference/programme Dr Graham Sinden, Oxford Environmental Change Institute: The implications of the Em’s 20/20/20 directive on renewable electricity generation requirements in the UK, and the potential role of offshore wind power in this context. (Graham Sinden has published a number of papers looking at the effects of integrating variable/intermittent generation into the generation mix) ]
^ http://www.awea.org/faq/basicwr.html Basic Principles of Wind Resource Evaluation, retrieved July 28, 2009
^ "Net Generation by Energy Source: Total (All Sectors)". Energy Information Administration (EIA), Dept. of Energy (DOE). September 11, 2009. http://www.eia.doe.gov/cneaf/electricity/epm/table1_1.html. Retrieved 2009-09-22.
^ "Existing Capacity by Energy Source". EIA, DOE. January 21, 2009. http://www.eia.doe.gov/cneaf/electricity/epa/epat2p2.html. Retrieved 2009-09-22.
^ a b World Wind Energy Association Statistics (PDF).
^ "Installed U.S. Wind Power Capacity Surged 45% in 2007". American Wind Energy Association. January 17, 2008. http://www.awea.org/newsroom/releases/AWEA_Market_Release_Q4_011708.html. Retrieved 2008-01-20.
^ "U.S. Wind Energy Projects". American Wind Energy Association. 2009-02-03. http://awea.org/projects. Retrieved 2009-02-03.
^ "Electric Power Monthly (January 2008 Edition)". Energy Information Administration. January 15, 2008. http://www.eia.doe.gov/cneaf/electricity/epm/epm_sum.html. Retrieved 2008-01-15.
^ "Massachusetts — 50 m Wind Power" (JPEG). U.S. National Renewable Energy Laboratory. 6 February 2007. http://www.eere.energy.gov/windandhydro/windpoweringamerica/images/windmaps/ma_50m_800.jpg. Retrieved 2008-01-15.
^ Lester R. Brown. (2008). Want a Better Way to Power Your Car? It's a Breeze. Washington Post.
^ Bradley, David (2004-02-06). "A Great Potential: The Great Lakes as a Regional Renewable Energy Source". http://greengold.org/wind/documents/107.pdf. Retrieved 2008-10-04.
^ "Great Lakes eyed for offshore wind farms". MSNBC, Associated Press. 2008-10-31. http://www.msnbc.msn.com/id/27436310/. Retrieved 2008-11-14.
^ Lema, Adrian and Kristian Ruby, ”Between fragmented authoritarianism and policy coordination: Creating a Chinese market for wind energy”, Energy Policy, Vol. 35, Issue 7, July 2007.
^ a b Watts, Jonathan (2008-07-25). "Energy in China: 'We call it the Three Gorges of the sky. The dam there taps water, we tap wind'". The Guardian. http://www.guardian.co.uk/environment/2008/jul/25/renewableenergy.alternativeenergy. Retrieved 2008-10-07.
^ "Tapping the Wind — India". February 2005. http://www.tve.org/ho/doc.cfm?aid=1678&lang=English. Retrieved 2006-10-28.
^ Watts, Himangshu (November 11 2003). "Clean Energy Brings Windfall to Indian Village". Reuters News Service. http://www.planetark.com/dailynewsstory.cfm/newsid/22758/story.htm. Retrieved 2006-10-28.
^ "Atlas do Potencial Eólico Brasileiro". http://www.cresesb.cepel.br/atlas_eolico_brasil/atlas-web.htm. Retrieved 2006-04-21.
^ "Eletrobrás — Centrais Elétricas Brasileiras S. A — Projeto Proinfa". http://www.eletrobras.gov.br/EM_Programas_Proinfa/default.asp. Retrieved 2006-04-21.
^ "Wind Energy: Rapid Growth" (PDF). Canadian Wind Energy Association. http://www.canwea.ca/downloads/en/PDFS/Rapid_growth_eng_April_06.pdf. Retrieved 2006-04-21.
^ "Canada's Current Installed Capacity" (PDF). Canadian Wind Energy Association. http://www.canwea.ca/images/uploads/File/fiche_anglais_Dec_2006.pdf. Retrieved 2006-12-11.
^ "Standard Offer Contracts Arrive In Ontario". Ontario Sustainable Energy Association. 2006. http://www.ontario-sea.org/whatsnew.html. Retrieved 2006-04-21.
^ "Call for Tenders A/O 2005-03: Wind Power 2,000 MW". Hydro-Québec. http://www.hydroquebec.com/distribution/en/marchequebecois/ao_200503/index.html. Retrieved 2006-04-21.
^ BP.com
^ 2005 月电力概况 (Chinese)
^ 2006 月电力概况 (Chinese)
^ Energy Information Administration - International Electricity Generation Data
^ International Energy Statistics
^ 深度分析产品 (Chinese)
^ 全国电力建设与投资结构继续加快调整 (Chinese)
^ Dati statistici sull’energia elettrica in Italia nel 2007 (Italian)
^ International Electricity Consumption
^ CIA - The World Factbook - Rank Order - Electricity - consumption
^ Small-scale wind energy
^ Windy Cities? New research into the urban wind resource
^ The Potential Of Small-Scale Wind Energy
^ Active filtering and load balancing with small wind energy systems
^ a b Helm, D. D. Helm and C. Hepburn (eds) (October 2009). EU climate-change policy-a critique. From: "The Economics and Politics of Climate Change". Oxford University Press. http://www.dieterhelm.co.uk/publications/SS_EU_CC_Critique.pdf. Retrieved September 6, 2009.
^ House of Lords Economic Affairs Select Committee (November 12, 2008). "Chapter 7: Recommendations and Conclusions. In: Economic Affairs – Fourth Report, Session 2007-2008. The Economics of Renewable Energy". UK Parliament website. http://www.publications.parliament.uk/pa/ld200708/ldselect/ldeconaf/195/19510.htm. Retrieved September 6, 2009.
^ BWEA report on onshore wind costs (PDF).
^ ""International Energy Outlook", 2006". Energy Information Administration. pp. 66. http://www.eia.doe.gov/oiaf/archive/ieo06/special_topics.html.
^ Helming, Troy (2004) "Uncle Sam's New Year's Resolution" ArizonaEnergy.org
^ a b Continuing boom in wind energy – 20 GW of new capacity in 2007
^ Global Wind 2005 Report
^ Wind turbine shortage continues; costs rising
^ Fact sheet 4: Tourism
^ a b BTM Forecasts 340-GW of Wind Energy by 2013
^ a b BTM Consult (2009). International Wind Energy Development World Market Update 2009
^ Archer, Cristina L.; Mark Z. Jacobson (2005). "Evaluation of global wind power". http://www.stanford.edu/group/efmh/winds/global_winds.html. Retrieved 2006-04-21.
^ http://www.claverton-energy.com/two-terawatts-average-power-output-the-uk-offshore-wind-resource.html
^ "Wind and Solar Power Systems — Design, analysis and Operation" (2nd ed., 2006), Mukund R. Patel, p. 303
^ Wind Plants of California's Altamont Pass
^ Green-e.org Retrieved on 20 May 2009
^ Buller, Erin (2008-07-11). "Capturing the wind". Uinta County Herald. http://www.uintacountyherald.com/V2_news_articles.php?heading=0&page=72&story_id=1299. Retrieved 2008-12-04. "The animals don’t care at all. We find cows and antelope napping in the shade of the turbines." - Mike Cadieux, site manager, Wyoming Wind Farm
^ Sovacool, B. K. (2009). "Contextualizing avian mortality: A preliminary appraisal of bird and bat fatalities from wind, fossil-fuel, and nuclear electricity". Energy Policy 37: 2241–2248. doi:10.1016/j.enpol.2009.02.011. edit
^ Wind farms are not only beautiful, they're absolutely necessary
[edit] External links
American Wind Energy Association (AWEA)
British Wind Energy Association (BWEA) Briefing Sheets
Canadian Wind Energy Association (CANWEA)
Chinese Wind Energy Association (CWEA)
Danish Wind Industry Association
Environmental and Energy Study Institute (EESI)
European Wind Energy Association (EWEA)
German Wind Energy Association (BWE)
Global Wind Energy Council (GWEC)
Indian Wind Energy Association (InWEA)
WindPower Television (WindpowerTV.com)
How electricity is produced using Wind Energy
Wind Power in the United States: Technology, Economic, and Policy Issues (53p), Congressional Research Service, June 2008
[edit] Wind power projects
The Red Barn Wind Project - A Community Wind Power Plant being developed in Arkansas
Jim Gordon's Nantucket Wind Energy Project
Trillium Power - Offshore Wind in The Great Lakes
Database of projects throughout the whole World
Database of offshore wind projects in North America
New York state wind projects (Wind Power Law Blog)
Wind Project Community Organizing - This free website includes dozens of current articles, links and resources about windpower, problem issues, community programs, case studies, lesson plans, etc.
Wind-powered vehicles.
Wind fuels
Inventing a super-kite to tap the energy of high-altitude wind, Feb 2009 (TED conference video), 5:25 min.
Wind energy: Pros and Cons
[hide]v • d • eWind power
Wind power Wind power · Wind turbine · Windmill · Wind-powered vehicle · History · Environmental effects
Wind turbines Airborne · Darrieus · Design · Savonius · Small · Unconventional · Vertical axis · Floating
Wind power industry Manufacturers · Consultants · Wind farm management · Software
Wind farms List of offshore wind farms · List of onshore wind farms · Community-owned
Concepts Betz' law · Capacity factor · EROEI · Grid energy storage · HVDC · Intermittency · Net energy gain · Storage · Subsidies · Wind power forecasting · Wind profile power law · Wind resource assessment
[show]v • d • eWind power by country
Overview Wind power industry · Installed wind power capacity
Regions Asia · Europe (EU)
by country Australia · Austria · Belgium · Brazil · Canada · China · Denmark · Estonia · Finland · France · Germany · Greece · India · Iran · Ireland · Italy · Japan · Morocco · Netherlands · New Zealand · Pakistan · Poland · Portugal · Romania · Russia · Spain · Sweden · Turkey · United Kingdom · United States
Portals: Energy · Sustainable development
[show]v • d • eElectricity generation
Concepts Availability factor · Baseload · Black start · Capacity factor · Demand management · EROEI · Grid storage · Intermittency · Load following · Peak demand · Spark spread
Sources Nonrenewable Coal · Fossil fuel power plant · Natural gas · Petroleum · Nuclear · Oil shale
Renewable Biomass · Geothermal · Hydro · Marine · Pumped hydro · Solar · Wind · Nuclear (Breeder)
Technology AC power · Cogeneration · Combined cycle · Cooling tower · Induction generator · Micro CHP · Microgeneration · Rankine cycle · Virtual power plant
Distribution Demand response · Distributed generation · Dynamic demand · Electricity distribution · Electrical grid · High-voltage direct current · Load control · Negawatts · Pylon · Smart grid · Super grid · TSO
Policies Carbon offset · Coal phase out · Ecotax · Energy subsidies · Feed-in Tariff · Net metering · Pigovian tax · Renewable Energy Certificates · Renewable energy payments · Renewable energy policy
Categories: Electricity distribution · Electricity economics · Power station technology · Portals: Energy · Sustainable development
[show]v • d • eApplication of wind energy
Wind power Wind turbine · Wind mill
Propulsion Sailboat · Sailing ship · Power kite · SkySails · Ice boat · Land sailing · Rotor ship
Kite applications Kite · Man-lifting kite
Air current Windcatcher
Retrieved from "http://en.wikipedia.org/wiki/Wind_power"
Categories: Wind power
Hidden categories: All articles with unsourced statements | Articles with unsourced statements from September 2009 | NPOV disputes from September 2009 | All NPOV disputes | Articles containing potentially dated statements from 2005 | All articles containing potentially dated statements | Articles with unsourced statements from October 2007 | Articles needing additional references from August 2008 | All articles needing additional references
ViewsArticle Discussion Edit this page History Personal toolsTry Beta Log in / create account Navigation
Main page
Contents
Featured content
Current events
Random article
Search
Interaction
About Wikipedia
Community portal
Recent changes
Contact Wikipedia
Donate to Wikipedia
Help
Toolbox
What links here
Related changes
Upload file
Special pages
Printable version
Permanent link
Cite this page
Languages
Afrikaans
العربية
Aragonés
Azərbaycan
Bân-lâm-gú
Беларуская
Беларуская (тарашкевіца)
Bosanski
Български
Català
Česky
Cymraeg
Dansk
Deutsch
Eesti
Ελληνικά
Español
Esperanto
Euskara
فارسی
Français
Gàidhlig
Galego
한국어
हिन्दी
Hrvatski
Bahasa Indonesia
Íslenska
Italiano
עברית
Latviešu
Lietuvių
Magyar
Nederlands
日本語
Norsk (bokmål)
Norsk (nynorsk)
Polski
Português
Română
Runa Simi
Русский
Slovenčina
Slovenščina
Српски / Srpski
Srpskohrvatski / Српскохрватски
Suomi
Svenska
தமிழ்
తెలుగు
ไทย
Türkçe
Українська
Tiếng Việt
粵語
Žemaitėška
中文
This page was last modified on 19 November 2009 at 19:38. Text is available under the Creative Commons Attribution-ShareAlike License; additional terms may apply. See Terms of Use for details.
Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization.Contact us Privacy policy About Wikipedia Disclaimers
tidal energy
Renewable Energy Search: GO Advanced Search | AEoogle Search AENewsDirectory IndexSubmit a SiteLatest SitesMost PopularContactRSSRenewable Energy Directory Tidal EnergySTATISTICSTotal Sites: 1516
New Today: 3
Total Categories: 32
CATEGORIESAlternative Energy
Alternative Fuels
Batteries
Biodiesel
Electric Bikes
Electric Cars
Electricity
Energy Conservation
Environment
Ethanol
Free Energy
Fuel Cells
Gasification
Geothermal Energy
Global Warming
Human Power
Hybrid Cars
Hydro Power
Hydrogen
Micro Hydro
Ocean Energy
Peak Oil
Pedal Power
Solar Energy
Steam Power
Sustainability
Technology
Tidal Energy
Transportation
Waste Energy
Wave Power
Wind Energy
Web directory of information about tidal power, tidal power plants and tidal energy uses.
All Sites Sort by: PageRank | Hits | Alphabetical
PR: 5 Energy Resources: Tidal power
The tide moves a huge amount of water twice each day, and harnessing it could provide a great deal of energy - around 20% of Britains needs.
More info
PR: 5 Tidal Power - PESWiki
Harnessing the in and out fluctuations of tidal waters. Covering everything from research and development to commercial applications worldwide. Since at least 1958, man has been harnessing the power of tides to produce electricity.
More info
PR: 5 Marine Current Turbines
Marine Current Turbines Ltd (MCT) is the world leader in the development of new technology for exploiting tidal currents for large-scale power generation.
More info
PR: 5 Blue Energy
At Blue Energy we have made an investment in the worlds oceans as the lifeblood of the planet. Not only are they a critical source of oxygen and habitat, but they are one of our largest untapped sources of renewable energy.
More info
PR: 4 Tidal Power Energy
Tidal Power Energy - North Atlantic Energy Structures Harnessing The Power Of The Moon Through Tidal Energy.
More info
PR: 4 How Tidal Power Plants Work
How tidal power plants work - history of tidal mills and ocean energy and how they work.
More info
PR: 3 Tidal Power
Tidal energy is produced through the use of tidal energy generators. These large underwater turbines are placed in areas with high tidal movements, and are designed to capture the kinetic motion of the ebbing and surging of ocean tides.
More info
PR: 3 Tidal Energy Pty Ltd
Tidal Energy Pty Ltd was formed in 1998 by the developers who personally hold patents to the technology.
More info
PR: 3 Tidestream
A look at current companies, technologies and projects in the UK tidal turbine market.
More info
PR: 3 Crest Energy
Crest Energy plans to generate power for 250,000 NZ homes, or 200 MW, by harnessing about 2.5% of the power of the tidal flows in to and out of the Kaipara Harbour.
More info
N/A Tidal Power Information
If there is one thing we can safely predict and be sure of on this planet, it is the coming and going of the tide. This gives this form of renewable energy a distinct advantage over other sources that are not as predictable and reliable.
More info
N/A Tidal Energy Forum
Forum for discussions about ocean energy technologies such as tidal energy, wave energy and ocean energy bionics.
More info
SPONSORS
Directory |Link to Us |Privacy Policy |Contact
Powered by Alternative Energy andAEoogle
Alternative Energy on Facebook
Created with PHPLD
New Today: 3
Total Categories: 32
CATEGORIESAlternative Energy
Alternative Fuels
Batteries
Biodiesel
Electric Bikes
Electric Cars
Electricity
Energy Conservation
Environment
Ethanol
Free Energy
Fuel Cells
Gasification
Geothermal Energy
Global Warming
Human Power
Hybrid Cars
Hydro Power
Hydrogen
Micro Hydro
Ocean Energy
Peak Oil
Pedal Power
Solar Energy
Steam Power
Sustainability
Technology
Tidal Energy
Transportation
Waste Energy
Wave Power
Wind Energy
Web directory of information about tidal power, tidal power plants and tidal energy uses.
All Sites Sort by: PageRank | Hits | Alphabetical
PR: 5 Energy Resources: Tidal power
The tide moves a huge amount of water twice each day, and harnessing it could provide a great deal of energy - around 20% of Britains needs.
More info
PR: 5 Tidal Power - PESWiki
Harnessing the in and out fluctuations of tidal waters. Covering everything from research and development to commercial applications worldwide. Since at least 1958, man has been harnessing the power of tides to produce electricity.
More info
PR: 5 Marine Current Turbines
Marine Current Turbines Ltd (MCT) is the world leader in the development of new technology for exploiting tidal currents for large-scale power generation.
More info
PR: 5 Blue Energy
At Blue Energy we have made an investment in the worlds oceans as the lifeblood of the planet. Not only are they a critical source of oxygen and habitat, but they are one of our largest untapped sources of renewable energy.
More info
PR: 4 Tidal Power Energy
Tidal Power Energy - North Atlantic Energy Structures Harnessing The Power Of The Moon Through Tidal Energy.
More info
PR: 4 How Tidal Power Plants Work
How tidal power plants work - history of tidal mills and ocean energy and how they work.
More info
PR: 3 Tidal Power
Tidal energy is produced through the use of tidal energy generators. These large underwater turbines are placed in areas with high tidal movements, and are designed to capture the kinetic motion of the ebbing and surging of ocean tides.
More info
PR: 3 Tidal Energy Pty Ltd
Tidal Energy Pty Ltd was formed in 1998 by the developers who personally hold patents to the technology.
More info
PR: 3 Tidestream
A look at current companies, technologies and projects in the UK tidal turbine market.
More info
PR: 3 Crest Energy
Crest Energy plans to generate power for 250,000 NZ homes, or 200 MW, by harnessing about 2.5% of the power of the tidal flows in to and out of the Kaipara Harbour.
More info
N/A Tidal Power Information
If there is one thing we can safely predict and be sure of on this planet, it is the coming and going of the tide. This gives this form of renewable energy a distinct advantage over other sources that are not as predictable and reliable.
More info
N/A Tidal Energy Forum
Forum for discussions about ocean energy technologies such as tidal energy, wave energy and ocean energy bionics.
More info
SPONSORS
Directory |Link to Us |Privacy Policy |Contact
Powered by Alternative Energy andAEoogle
Alternative Energy on Facebook
Created with PHPLD
Tidal power
You depend on us, now we need your help.
Support Wikipedia today. $0.9M USD$7.5M USDDonate Now[Hide][Show]Wikipedia Forever Our shared knowledge. Our shared treasure. Help us protect it. [Show]Wikipedia Forever Our shared knowledge. Our shared treasure. Help us protect it. Tidal power
From Wikipedia, the free encyclopedia
Jump to: navigation, search
The world's first commercial axial turbine [3] tidal stream generator — SeaGen — in Strangford Lough. The strong wake shows the power in the tidal current.Renewable energy
Biofuel
Biomass
Geothermal
Hydroelectricity
Solar energy
Tidal power
Wave power
Wind power
v • d • e
Tidal power, sometimes called tidal energy, is a form of hydropower that converts the energy of tides into electricity or other useful forms of power.
Although not yet widely used, tidal power has potential for future electricity generation. Tides are more predictable than wind energy and solar power. Historically, tide mills have been used, both in Europe and on the Atlantic coast of North America. The earliest occurrences date from the Middle Ages, or even from Roman times.[1][2]
Contents [hide]
1 Generation of tidal energy
2 Categories of tidal power
3 Tidal stream generators
3.1 Engineering approaches
3.1.1 Axial Turbines
3.1.2 Vertical and horizontal axis crossflow turbines
3.1.3 Oscillating devices
3.1.4 Venturi effect
3.2 Commercial plans
3.3 Energy calculations
3.4 Potential sites
4 Barrage tidal power
4.1 Ebb generation
4.2 Flood generation
4.3 Pumping
4.4 Two-basin schemes
4.5 Environmental impact
4.5.1 Turbidity
4.5.2 Tidal fences and turbines
4.5.3 Salinity
4.5.4 Sediment movements
4.5.5 Fish
4.6 Energy calculations
4.6.1 Example calculation of tidal power generation
4.7 Economics
5 Mathematical modeling of tidal schemes
6 Global environmental impact
7 Operating tidal power schemes
8 Tidal power schemes being considered
9 See also
10 References
11 Notes
12 External links
[edit] Generation of tidal energy
Main articles: Tide and Tidal acceleration
Tidal power is the only form of energy which derives directly from the relative motions of the Earth–Moon system, and to a lesser extent from the Earth–Sun system. The tidal forces produced by the Moon and Sun, in combination with Earth's rotation, are responsible for the generation of the tides. Other sources of energy originate directly or indirectly from the Sun, including fossil fuels, conventional hydroelectric, wind, biofuels, wave power and solar. Nuclear is derived using radioactive material from the Earth, geothermal power uses the Earth's internal heat which comes from a combination of residual heat from planetary accretion (about 20%) and heat produced through radioactive decay (80%).[3]
Variation of tides over a dayTidal energy is generated by the relative motion of the Earth, Sun and the Moon, which interact via gravitational forces. Periodic changes of water levels, and associated tidal currents, are due to the gravitational attraction by the Sun and Moon. The magnitude of the tide at a location is the result of the changing positions of the Moon and Sun relative to the Earth, the effects of Earth rotation, and the local shape of the sea floor and coastlines.
Because the Earth's tides are caused by the tidal forces due to gravitational interaction with the Moon and Sun, and the Earth's rotation, tidal power is practically inexhaustible and classified as a renewable energy source.
A tidal energy generator uses this phenomenon to generate energy. The stronger the tide, either in water level height or tidal current velocities, the greater the potential for tidal energy generation.
Tidal movement causes a continual loss of mechanical energy in the Earth–Moon system due to pumping of water through the natural restrictions around coastlines, and due to viscous dissipation at the seabed and in turbulence. This loss of energy has caused the rotation of the Earth to slow in the 4.5 billion years since formation. During the last 620 million years the period of rotation has increased from 21.9 hours to the 24 hours[4] we see now; in this period the Earth has lost 17% of its rotational energy. While tidal power may take additional energy from the system, increasing the rate of slowdown, the effect would be noticeable over millions of years only, thus being negligible.
[edit] Categories of tidal power
Tidal power can be classified into three main types:
Tidal stream systems make use of the kinetic energy of moving water to power turbines, in a similar way to windmills that use moving air. This method is gaining in popularity because of the lower cost and lower ecological impact compared to barrages.
Barrages make use of the potential energy in the difference in height (or head) between high and low tides. Barrages are essentially dams across the full width of a tidal estuary, and suffer from very high civil infrastructure costs, a worldwide shortage of viable sites, and environmental issues.
Tidal lagoons, are similar to barrages, but can be constructed as self contained structures, not fully across an estuary, and are claimed to incur much lower cost and impact overall. Furthermore they can be configured to generate continuously which is not the case with barrages.
Modern advances in turbine technology may eventually see large amounts of power generated from the ocean, especially tidal currents using the tidal stream designs but also from the major thermal current systems such as the Gulf Stream, which is covered by the more general term marine current power. Tidal stream turbines may be arrayed in high-velocity areas where natural tidal current flows are concentrated such as the west and east coasts of Canada, the Strait of Gibraltar, the Bosporus, and numerous sites in Southeast Asia and Australia. Such flows occur almost anywhere where there are entrances to bays and rivers, or between land masses where water currents are concentrated.
[edit] Tidal stream generators
A relatively new technology, though first conceived in the 1970s during the oil crisis[5], tidal stream generators draw energy from currents in much the same way as wind turbines. The higher density of water, 800 times the density of air, means that a single generator can provide significant power at low tidal flow velocities (compared with wind speed).[6] Given that power varies with the density of medium and the cube of velocity, it is simple to see that water speeds of nearly one-tenth of the speed of wind provide the same power for the same size of turbine system. However this limits the application in practice to places where the tide moves at speeds of at least 2 knots (1m/s) even close to neap tides.
Since tidal stream generators are an immature technology (no commercial scale production facilities are yet routinely supplying power), no standard technology has yet emerged as the clear winner, but a large variety of designs are being experimented with, some very close to large scale deployment. Several prototypes have shown promise with many companies making bold claims, some of which are yet to be independently verified, but they have not operated commercially for extended periods to establish performances and rates of return on investments.
[edit] Engineering approaches
The European Marine Energy Centre[7] categorises them under four heads although a number of other approaches are also being tried.
[edit] Axial Turbines
Evopod - A semi-submerged floating approach tested in Strangford Lough.These are close in concept to traditional windmills operating under the sea and have the most prototypes currently operating. These include:
Kvalsund, south of Hammerfest, Norway.[8] Although still a prototype, a turbine with a reported capacity of 300 kW was connected to the grid on 13 November 2003.
A 300 kW Periodflow marine current propeller type turbine — Seaflow — was installed by Marine Current Turbines off the coast of Lynmouth, Devon, England, in 2003.[9] The 11m diameter turbine generator was fitted to a steel pile which was driven into the seabed. As a prototype, it was connected to a dump load, not to the grid.
Since April 2007 Verdant Power[10] has been running a prototype project in the East River between Queens and Roosevelt Island in New York City; it was the first major tidal-power project in the United States.[11] The strong currents pose challenges to the design: the blades of the 2006 and 2007 prototypes broke off, and new reinforced turbines were installed in September 2008.[12][13]
Following the Seaflow trial, a fullsize prototype, called SeaGen, was installed by Marine Current Turbines in Strangford Lough in Northern Ireland in April 2008. The turbine began to generate at full power of just over 1.2 MW in December 2008[14] and was reported to have fed 150 kW into the grid for the first time on 17 July 2008.[15] It is currently the only commercial scale device to have been installed anywhere in the world.[16] SeaGen is made up of two axial flow rotors, each of which drive a generator. The turbines are capable of generating electricity on both the ebb and flood tides because the rotor blades can pitch through 180˚.[17]
OpenHydro,[18] an Irish company exploiting the Open-Centre Turbine developed in the U.S., has a prototype being tested at the European Marine Energy Centre (EMEC), in Orkney, Scotland.
A prototype semi-submerged floating tethered tidal turbine called Evopod has been tested since June 2008[19] in Strangford Lough, Northern Ireland at 1/10th scale. The company developing it is called Ocean Flow Energy Ltd[20], and they are based in the UK. The advanced hull form maintains optimum heading into the tidal stream and it is designed to operate in the peak flow of the water column.
[edit] Vertical and horizontal axis crossflow turbines
Invented by Georges Darreius in 1923 and Patented in 1929, these are crossflow turbines that can be deployed either vertically or horizontally.
The Gorlov turbine[21] is a variant of the Darrieus design featuring a helical design which is being commercially piloted on a large scale in S. Korea,[22] starting with a 1MW plant that started in May 2009[23] and expanding to 90MW by 2013. Neptune Renewable Energy has developed Proteus[24] which uses a barrage of vertical axis crossflow turbines for use mainly in estuaries.
In late April 2008, Ocean Renewable Power Company, LLC (ORPC) [4] successfully completed the testing of its proprietary turbine-generator unit (TGU) prototype at ORPC’s Cobscook Bay and Western Passage tidal sites near Eastport, Maine.[25] The TGU is the core of the OCGen technology and utilizes advanced design cross-flow (ADCF) turbines to drive a permanent magnet generator located between the turbines and mounted on the same shaft. ORPC has developed TGU designs that can be used for generating power from river, tidal and deep water ocean currents.
[edit] Oscillating devices
Oscillating devices do not have a rotating component, instead making use of aerofoil sections which are pushed sideways by the flow. Oscillating stream power extraction was proven with the omni- or bi-directional Wing'd Pump windmill.[26] During 2003 a 150 kW oscillating hydroplane device, the Stingray, was tested off the Scottish coast.[27] The Stingray uses hydrofoils to create oscillation, which allows it to create hydraulic power. This hydraulic power is then used to power a hydraulic motor, which then turns a generator.[28]
[edit] Venturi effect
Further information: Venturi effect
This uses a shroud to increase the flow rate through the turbine. These can be mounted horizontally or vertically.
The Australian company Tidal Energy Pty Ltd undertook successful commercial trials of highly efficient shrouded tidal turbines on the Gold Coast, Queensland in 2002. Tidal Energy has commenced a rollout of their shrouded turbine for a remote Australian community in northern Australia where there are some of the fastest flows ever recorded (11 m/s, 21 knots) – two small turbines will provide 3.5 MW. Another larger 5 meter diameter turbine, capable of 800 kW in 4 m/s of flow, is planned for deployment as a tidal powered desalination showcase near Brisbane Australia in October 2008. Another device, the Hydro Venturi, is to be tested in San Francisco Bay.[29]
Trials in the Strait of Messina, Italy, started in 2001 of the Kobold concept.[30]
[edit] Commercial plans
RWE's npower announced that it is in partnership with Marine Current Turbines to build a tidal farm of SeaGen turbines off the coast of Anglesey in Wales.[31]
In November 2007, British company Lunar Energy announced that, in conjunction with E.ON, they would be building the world's first tidal energy farm off the coast of Pembrokshire in Wales. It will be the world's first deep-sea tidal-energy farm and will provide electricity for 5,000 homes. Eight underwater turbines, each 25 metres long and 15 metres high, are to be installed on the sea bottom off St David's peninsula. Construction is due to start in the summer of 2008 and the proposed tidal energy turbines, described as "a wind farm under the sea", should be operational by 2010.
British Columbia Tidal Energy Corp. plans to deploy at least three 1.2 MW turbines in the Campbell River or in the surrounding coastline of British Columbia by 2009.[32]
An organisation named Alderney Renewable Energy Ltd is planning to use tidal turbines to extract power from the notoriously strong tidal races around Alderney in the Channel Islands. It is estimated that up to 3GW could be extracted. This would not only supply the island's needs but also leave a considerable surplus for export.[33]
Nova Scotia Power has selected OpenHydro's turbine for a tidal energy demonstration project in the Bay of Fundy, Nova Scotia, Canada and Alderney Renewable Energy Ltd for the supply of tidal turbines in the Channel Islands. Open Hydro
[edit] Energy calculations
Various turbine designs have varying efficiencies and therefore varying power output. If the efficiency of the turbine "Cp" is known the equation below can be used to determine the power output.
The energy available from these kinetic systems can be expressed as:
P = Cp x 0.5 x ρ x A x V³[34]
where:
Cp is the turbine coefficient of performance
P = the power generated (in watts)
ρ = the density of the water (seawater is 1025 kg/m³)
A = the sweep area of the turbine (in m²)
V³ = the velocity of the flow cubed (i.e. V x V x V)
Relative to an open turbine in free stream, shrouded turbines are capable of as much as 3 to 4 times the power of the same rotor in open flow, depending on the geometry of the shroud.[34] However, to measure the efficiency, one must compare the benefits of a larger rotor with the benefits of the shroud.
[edit] Potential sites
As with wind power, selection of location is critical for the tidal turbine. Tidal stream systems need to be located in areas with fast currents where natural flows are concentrated between obstructions, for example at the entrances to bays and rivers, around rocky points, headlands, or between islands or other land masses. The following potential sites are under serious consideration:
Pembrokeshire in Wales[35]
River Severn between Wales and England[36]
Cook Strait in New Zealand[37]
Kaipara Harbour in New Zealand[38]
Bay of Fundy[39] in Canada.
East River[40][41] in the USA
Golden Gate in the San Francisco Bay[42]
Piscataqua River in New Hampshire[43]
The Race of Alderney and The Swinge in the Channel Islands[33]
[edit] Barrage tidal power
Rance tidal power plant
An artistic impression of a tidal barrage, including embankments, a ship lock and caissons housing a sluice and two turbines.With only a few operating plants globally, a large 240 MW plant on the Rance River, and two small plants, one on the Bay of Fundy and the other across a tiny inlet in Kislaya Guba, Russia), and a suggested Severn barrage across the River Severn, from Brean Down in England to Lavernock Point near Cardiff in Wales, the barrage method of extracting tidal energy involves building a barrage across a bay or river, as in the case of the Rance tidal power plant in France. Turbines installed in the barrage wall generate power as water flows in and out of the estuary basin, bay, or river. These systems are similar to a hydro dam that produces Static Head or pressure head (a height of water pressure). When the water level outside of the basin or lagoon changes relative to the water level inside, the turbines are able to produce power. The largest such installation has been working on the Rance river, France, since 1966.
The basic elements of a barrage are caissons, embankments, sluices, turbines, and ship locks. Sluices, turbines, and ship locks are housed in caissons (very large concrete blocks). Embankments seal a basin where it is not sealed by caissons.
The sluice gates applicable to tidal power are the flap gate, vertical rising gate, radial gate, and rising sector.
Barrage systems are affected by problems of high civil infrastructure costs associated with what is in effect a dam being placed across estuarine systems, and the environmental problems associated with changing a large ecosystem.
Potentials for UK barrages are here. [44]
[edit] Ebb generation
The basin is filled through the sluices until high tide. Then the sluice gates are closed. (At this stage there may be "Pumping" to raise the level further). The turbine gates are kept closed until the sea level falls to create sufficient head across the barrage, and then are opened so that the turbines generate until the head is again low. Then the sluices are opened, turbines disconnected and the basin is filled again. The cycle repeats itself. Ebb generation (also known as outflow generation) takes its name because generation occurs as the tide changes tidal direction.
[edit] Flood generation
The basin is filled through the turbines, which generate at tide flood. This is generally much less efficient than ebb generation, because the volume contained in the upper half of the basin (which is where ebb generation operates) is greater than the volume of the lower half (filled first during flood generation). Therefore the available level difference — important for the turbine power produced — between the basin side and the sea side of the barrage, reduces more quickly than it would in ebb generation. Rivers flowing into the basin may further reduce the energy potential, instead of enhancing it as in ebb generation. Which of course is not a problem with the "lagoon" model, without river inflow.
[edit] Pumping
Turbines are able to be powered in reverse by excess energy in the grid to increase the water level in the basin at high tide (for ebb generation). This energy is more than returned during generation, because power output is strongly related to the head. If water is raised 2 ft (61 cm) by pumping on a high tide of 10 ft (3 m), this will have been raised by 12 ft (3.7 m) at low tide. The cost of a 2 ft rise is returned by the benefits of a 12 ft rise. This is since the correlation between the potential energy is not a linear relationship, rather, is related by the square of the tidal height variation.
[edit] Two-basin schemes
Another form of energy barrage configuration is that of the dual basin type. With two basins, one is filled at high tide and the other is emptied at low tide. Turbines are placed between the basins. Two-basin schemes offer advantages over normal schemes in that generation time can be adjusted with high flexibility and it is also possible to generate almost continuously. In normal estuarine situations, however, two-basin schemes are very expensive to construct due to the cost of the extra length of barrage. There are some favourable geographies, however, which are well suited to this type of scheme.
[edit] Environmental impact
The placement of a barrage into an estuary has a considerable effect on the water inside the basin and on the ecosystem. Many governments have been reluctant in recent times to grant approval for tidal barrages. Through research conducted on tidal plants, it has been found that tidal barrages constructed at the mouths of estuaries pose similar environmental threats as large dams. The construction of large tidal plants alters the flow of saltwater in and out of estuaries, which changes the hydrology and salinity and possibly negatively affects the marine mammals that use the estuaries as their habitat [45] The La Rance plant, off the Brittany coast of northern France, was the first and largest tidal barrage plant in the world. It is also the only site where a full-scale evaluation of the ecological impact of a tidal power system, operating for 20 years, has been made [46]
French researchers found that the isolation of the estuary during the construction phases of the tidal barrage was detrimental to flora and fauna, however; after ten years, there has been a “variable degree of biological adjustment to the new environmental conditions” [46]
Some species lost their habitat due to La Rance’s construction, but other species colonized the abandoned space, which caused a shift in diversity. Also as a result of the construction, sandbanks disappeared, the beach of St. Servan was badly damaged and high-speed currents have developed near sluices, which are water channels controlled by gates [47]
[edit] Turbidity
Turbidity (the amount of matter in suspension in the water) decreases as a result of smaller volume of water being exchanged between the basin and the sea. This lets light from the Sun to penetrate the water further, improving conditions for the phytoplankton. The changes propagate up the food chain, causing a general change in the ecosystem.
[edit] Tidal fences and turbines
Tidal fences and turbines can have varying environmental impacts depending on whether or not fences and turbines are constructed with regard to the environment. The main environmental impact of turbines is their impact on fish. If the turbines are moving slowly enough, such as low velocities of 25-50 rpm, fish kill is minimalized and silt and other nutrients are able to flow through the structures [45] For example, a 20 kW tidal turbine prototype built in the St. Lawrence Seaway in 1983 reported no fish kills [45] Tidal fences block off channels, which makes it difficult for fish and wildlife to migrate through those channels. In order to reduce fish kill, fences could be engineered so that the spaces between the caisson wall and the rotor foil are large enough to allow fish to pass through [45] Larger marine mammals such as seals or dolphins can be protected from the turbines by fences or a sonar sensor auto-breaking system that automatically shuts the turbines down when marine mammals are detected [45] Overall, many researches have argued that while tidal barrages pose environmental threats, tidal fences and tidal turbines, if constructed properly, are likely to be more environmentally benign. Unlike barrages, tidal fences and turbines do not block channels or estuarine mouths, interrupt fish migration or alter hydrology, thus, these options offer energy generating capacity without dire environmental impacts [45]
[edit] Salinity
As a result of less water exchange with the sea, the average salinity inside the basin decreases, also affecting the ecosystem.[citation needed] "Tidal Lagoons" do not suffer from this problem.[citation needed]
[edit] Sediment movements
Estuaries often have high volume of sediments moving through them, from the rivers to the sea. The introduction of a barrage into an estuary may result in sediment accumulation within the barrage, affecting the ecosystem and also the operation of the barrage.
[edit] Fish
Fish may move through sluices safely, but when these are closed, fish will seek out turbines and attempt to swim through them. Also, some fish will be unable to escape the water speed near a turbine and will be sucked through. Even with the most fish-friendly turbine design, fish mortality per pass is approximately 15%[citation needed] (from pressure drop, contact with blades, cavitation, etc.). Alternative passage technologies (fish ladders, fish lifts, fish escalators etc.) have so far failed to solve this problem for tidal barrages, either offering extremely expensive solutions, or ones which are used by a small fraction of fish only. Research in sonic guidance of fish is ongoing.[citation needed] The Open-Centre turbine reduces this problem allowing fish to pass through the open centre of the turbine.
Recently a run of the river type turbine has been developed in France. This is a very large slow rotating Kaplan type turbine mounted on an angle. Testing for fish mortality has indicated fish mortality figures to be less than 5%. This concept also seems very suitable for adaption to marine current/tidal turbines.[48]
[edit] Energy calculations
The energy available from a barrage is dependent on the volume of water. The potential energy contained in a volume of water is:[49]
where:
h is the vertical tidal range,
A is the horizontal area of the barrage basin,
ρ is the density of water = 1025 kg per cubic meter (seawater varies between 1021 and 1030 kg per cubic meter) and
g is the acceleration due to the Earth's gravity = 9.81 meters per second squared.
The factor half is due to the fact, that as the basin flows empty through the turbines, the hydraulic head over the dam reduces. The maximum head is only available at the moment of low water, assuming the high water level is still present in the basin.
[edit] Example calculation of tidal power generation
Assumptions:
Let us assume that the tidal range of tide at a particular place is 32 feet = 10 m (approx)
The surface of the tidal energy harnessing plant is 9 km² (3 km × 3 km)= 3000 m × 3000 m = 9 × 106 m2
Density of sea water = 1025.18 kg/m3
Mass of the sea water = volume of sea water × density of sea water
= (area × tidal range) of water × mass density
= (9 × 106 m2 × 10 m) × 1025.18 kg/m3
= 92 × 109 kg (approx)
Potential energy content of the water in the basin at high tide = ½ × area × density × gravitational acceleration × tidal range squared
= ½ × 9 × 106 m2 × 1025 kg/m3 × 9.81 m/s2 × (10 m)2
=4.5 × 1012 J (approx)
Now we have 2 high tides and 2 low tides every day. At low tide the potential energy is zero.
Therefore the total energy potential per day = Energy for a single high tide × 2
= 4.5 × 1012 J × 2
= 9 × 1012 J
Therefore, the mean power generation potential = Energy generation potential / time in 1 day
= 9 × 1012 J / 86400 s
= 104 MW
Assuming the power conversion efficiency to be 30%: The daily-average power generated = 104 MW * 30% / 100%
= 31 MW (approx)
A barrage is best placed in a location with very high-amplitude tides. Suitable locations are found in Russia, USA, Canada, Australia, Korea, the UK. Amplitudes of up to 17 m (56 ft) occur for example in the Bay of Fundy, where tidal resonance amplifies the tidal range.
[edit] Economics
Tidal barrage power schemes have a high capital cost and a very low running cost. As a result, a tidal power scheme may not produce returns for many years, and investors may be reluctant to participate in such projects.
Governments may be able to finance tidal barrage power, but many are unwilling to do so also due to the lag time before investment return and the high irreversible commitment. For example the energy policy of the United Kingdom[50] recognizes the role of tidal energy and expresses the need for local councils to understand the broader national goals of renewable energy in approving tidal projects. The UK government itself appreciates the technical viability and siting options available, but has failed to provide meaningful incentives to move these goals forward.
[edit] Mathematical modeling of tidal schemes
In mathematical modeling of a scheme design, the basin is broken into segments, each maintaining its own set of variables. Time is advanced in steps. Every step, neighbouring segments influence each other and variables are updated.
The simplest type of model is the flat estuary model, in which the whole basin is represented by one segment. The surface of the basin is assumed to be flat, hence the name. This model gives rough results and is used to compare many designs at the start of the design process.
In these models, the basin is broken into large segments (1D), squares (2D) or cubes (3D). The complexity and accuracy increases with dimension.
Mathematical modeling produces quantitative information for a range of parameters, including:
Water levels (during operation, construction, extreme conditions, etc.)
Currents
Waves
Power output
Turbidity
Salinity
Sediment movements
[edit] Global environmental impact
A tidal power scheme is a long-term source of electricity. A proposal for the Severn Barrage, if built, has been projected to save 18 million tonnes of coal per year of operation. This decreases the output of greenhouse gases into the atmosphere.
If fossil fuel resources decline during the 21st century, as predicted by Hubbert peak theory, tidal power is one of the alternative sources of energy that will need to be developed to satisfy the human demand for energy.
[edit] Operating tidal power schemes
The first tidal power station was the Rance tidal power plant built over a period of 6 years from 1960 to 1966 at La Rance, France.[51] It has 240 MW installed capacity.
The first tidal power site in North America is the Annapolis Royal Generating Station, Annapolis Royal, Nova Scotia, which opened in 1984 on an inlet of the Bay of Fundy.[52] It has 18 MW installed capacity.
The first in-stream tidal current generator in North America (Race Rocks Tidal Power Demonstration Project) was installed at Race Rocks on southern Vancouver Island in September 2006.[53][54] The next phase in the development of this tidal current generator will be in Nova Scotia.[55]
A small project was built by the Soviet Union at Kislaya Guba on the Barents Sea. It has 0.5 MW installed capacity. In 2006 it was upgraded with 1.2MW experimental advanced orthogonal turbine.
Jindo Uldolmok Tidal Power Plant in South Korea is a tidal stream generation scheme planned to be expanded progressively to 90 MW of capacity by 2013. The first 1 MW was installed in May 2009. [56]
1.2 MW SeaGen system became operational in late 2008 on Strangford Lough in Northern Ireland. [57]
[edit] Tidal power schemes being considered
In the table, "-" indicates missing information, "?" indicates information which has not been decided
Country Place Mean tidal range (m) Area of basin (km²) Maximum capacity (MW)
United Kingdom and Channel Islands River Severn 7.8 450 8640
Russia[58] Penzhinskaya Bay[59][60] 6.0 20,500 87,000
A 12MW project at Kislaya Guba in Russia with orthogonal turbines is under construction.
254 MW Sihwa Lake Tidal Power Plant in South Korea is under construction and planned to be completed by November 2009.[61]
China is developing a tidal lagoon near the mouth of the Yalu River.[62]
[edit] See also
Energy portal
Sustainable development portal
Category:Energy by country
Run-of-the-river hydroelectricity
Damless hydro
Marine current power
Stream energy
Ocean energy
Thermal energy
Wave power
World energy resources and consumption
[edit] References
Baker, A. C. 1991, Tidal power, Peter Peregrinus Ltd., London.
Baker, G. C., Wilson E. M., Miller, H., Gibson, R. A. & Ball, M., 1980. "The Annapolis tidal power pilot project", in Waterpower '79 Proceedings, ed. Anon, U.S. Government Printing Office, Washington, pp 550–559.
Hammons, T. J. 1993, "Tidal power", Proceedings of the IEEE, [Online], v81, n3, pp 419–433. Available from: IEEE/IEEE Xplore. [July 26, 2004].
Lecomber, R. 1979, "The evaluation of tidal power projects", in Tidal Power and Estuary Management, eds. Severn, R. T., Dineley, D. L. & Hawker, L. E., Henry Ling Ltd., Dorchester, pp 31–39.
[edit] Notes
^ Spain, Rob: "A possible Roman Tide Mill", Paper submitted to the Kent Archaeological Society
^ Minchinton, W. E. (October 1979). "Early Tide Mills: Some Problems". Technology and Culture 20 (4): 777–786. doi:10.2307/3103639.
^ Turcotte, D. L.; Schubert, G. (2002). "4". Geodynamics (2 ed.). Cambridge, England, UK: Cambridge University Press. pp. 136–137. ISBN 978-0-521-66624-4.
'^ George E. Williams. "Geological constraints on the Precambrian history of Earth's rotation and the Moon's orbit". Reviews of Geophysics '38 (2000), 37-60.
^ Jones, Anthony T., and Adam Westwood. "Power from the oceans: wind energy industries are growing, and as we look for alternative power sources, the growth potential is through the roof. Two industry watchers take a look at generating energy from wind and wave action and the potential to alter." The Futurist 39.1 (2005): 37(5). GALE Expanded Academic ASAP. Web. 8 Oct. 2009.
^ "Surfing Energy's New Wave: FOR CENTURIES, PEOPLE HAVE DREAMED OF HARNESSING THE POWER OF OCEAN TIDES. HAS A COMPANY IN WALES MADE THE DREAM COME TRUE?" Time International 16 June 2003: 52+. http://www.time.com/time/magazine/article/0,9171,457348,00.html
^ EMEC. "Tidal Energy Devices". http://www.emec.org.uk/tidal_devices.htm. Retrieved 5 October 2008.
^ First power station to harness Moon opens - September 22, 2003 - New Scientist
^ REUK: "Read about the first open-sea tidal turbine generator off Lynmouth, Devon"
^ Verdant Power
^ MIT Technology Review, April 2007 Accessed August 24, 2008]
^ Robin Shulman (September 20, 2008). "N.Y. Tests Turbines to Produce Power. City Taps Current Of the East River". Washington Post. http://www.washingtonpost.com/wp-dyn/content/article/2008/09/19/AR2008091903729.html. Retrieved 2008-10-09.
^ Kate Galbraith (September 22, 2008). "Power From the Restless Sea Stirs the Imagination". New York Times. http://www.nytimes.com/2008/09/23/business/23tidal.html?em. Retrieved 2008-10-09.
^ http://www.marineturbines.com/3/news/
^ First connection to the grid
^ · Sea Generation Tidal Turbine
^ Marine Current Turbines. "Technology." Marine Current Turbines. Marine Current Turbines, n.d. Web. 5 Oct. 2009.
^ OpenHydro
^ [1] Ocean Flow Energy Ltd annouce the start of their testing in Strangford Lough
^ Ocean Flow Energy company website
^ Gorlov Turbine
^ Gorlov Turbines in Koreas
^ "South Korea starts up, to expand 1-MW Jindo Uldolmok tidal project". Hydro World. 2009. http://www.hydroworld.com/index/display/article-display/2336952618/articles/hrhrw/hydroindustrynews/ocean-tidal-streampower/south-korea_starts.html.
^ Proteus
^ "Tide is slowly rising in interest in ocean power". Mass High Tech: The Journal of New England Technology. August 1, 2008. http://www.masshightech.com/stories/2008/07/28/weekly9-Tide-is-slowly-rising-in-interest-in-ocean-power.html/. Retrieved 2008-10-11.
^ Wing'd Pump Windmill
^ Stingray
^ Jones, Anthony T., and Adam Westwood. "Power from the oceans: wind energy industries are growing, and as we look for alternative power sources, the growth potential is through the roof. Two industry watchers take a look at generating energy from wind and wave action and the potential to alter." The Futurist 39.1 (2005): 37(5). GALE Expanded Academic ASAP. Web. 8 Oct. 2009.
^ San Francisco Bay Guardian News
^ A.D.A.Group
^ RWE plans 10.5 MW sea current power plant off Welsh coast - Forbes.com
^ Tidal Power Coming to West Coast of Canada
^ a b Alderney Renewable Energy Ltd
^ a b http://www.cyberiad.net/library/pdf/bk_tidal_paper25apr06.pdf tidal paper on cyberiad.net
^ Builder & Engineer - Pembrokeshire tidal barrage moves forward
^ Severn balancing act
^ NZ: Chance to turn the tide of power supply | EnergyBulletin.net | Peak Oil News Clearinghouse
^ Harnessing the power of the sea Energy NZ, Vol 1, No 1, Winter 2007.
^ Bay of Fundy to get three test turbines | Cleantech.com
^ Shulman, Robin (September 20, 2008). "N.Y. Tests Turbines to Produce Power". The Washington Post. ISSN 0740-5421. http://www.washingtonpost.com/wp-dyn/content/article/2008/09/19/AR2008091903729.html?hpid=topnews&sub=AR. Retrieved 2008-09-20.
^ Verdant Power
^ http://deanzaemtp.googlepages.com/PGEbacksnewstudyofbaystidalpower.pdf
^ Tidal power from Piscataqua River?
^ http://www.claverton-energy.com/tidal-barrage-potential-in-england.html
^ a b c d e f Pelc, Robin and Fujita, Rob. Renewable energy from the ocean.
^ a b Retiere, C. Tidal power and aquatic environment of La Rance.
^ Charlier, Roger. Forty candles for the Rance River TPP tides provide renewable and sustainable power generation
^ VLH TURBINE
^ Lamb, H. (1994). Hydrodynamics (6th edition ed.). Cambridge University Press. ISBN 9780521458689. §174, p. 260.
^ [2] (see for example key principles 4 and 6 within Planning Policy Statement 22)
^ L'Usine marémotrice de la Rance
^ Nova Scotia Power - Environment - Green Power- Tidal
^ Race Rocks Demonstration Project
^ Tidal Energy, Ocean Energy
^ Information for media inquiries
^ Korea's first tidal power plant built in Uldolmok, Jindo
^ http://news.bbc.co.uk/2/hi/uk_news/northern_ireland/7790494.stm
^ http://www.elektropages.ru/article/4_2006_ELEKTRO.html
^ Russian power plants soon to utilize tidal energy :: Russia-InfoCentre
^ http://www.severnestuary.net/sep/pdfs/managingtidalchangeprojectreport-phase1final.pdf
^ Sihwa Lake Tidal Power Plant targets completion by late 2009
^ China Endorses 300 MW Ocean Energy Project
[edit] External links
Wikimedia Commons has media related to: Tidal power
Marine and Hydrokinetic Technology Database The U.S. Department of Energy’s Marine and Hydrokinetic Technology Database provides up-to-date information on marine and hydrokinetic renewable energy, both in the U.S. and around the world.
Severn Estuary Partnership: Tidal Power Resource Page
Location of Potential Tidal Stream Power sites in the UK
University of Strathclyde ESRU-- Detailed analysis of marine energy resource, current energy capture technology appraisal and environmental impact outline
Coastal Research - Foreland Point Tidal Turbine and warnings on proposed Severn Barrage
Sustainable Development Commission - Report looking at 'Tidal Power in the UK', including proposals for a Severn barrage
World Energy Council - Report on Tidal Energy
Wave and Tidal Energy News
How electricity is produced using Tidal Energy ?
[hide]v • d • eOcean energy
Wave power Australia • New Zealand
Tidal power New Zealand •Annapolis Royal Generating Station
Osmotic power
Other Marine current power • Ocean engineering • Ocean thermal energy conversion • Pelamis wave energy converter • Wind power (offshore) • Wave farm
Portals: Energy • Sustainable development
Retrieved from "http://en.wikipedia.org/wiki/Tidal_power"
Categories: Energy from oceans and water | Tidal power | Coastal construction | Tides
Hidden categories: All articles with unsourced statements | Articles with unsourced statements from August 2008 | Articles with unsourced statements from August 2007 | Articles with unsourced statements from February 2008
ViewsArticle Discussion Edit this page History Personal toolsTry Beta Log in / create account Navigation
Main page
Contents
Featured content
Current events
Random article
Search
Interaction
About Wikipedia
Community portal
Recent changes
Contact Wikipedia
Donate to Wikipedia
Help
Toolbox
What links here
Related changes
Upload file
Special pages
Printable version
Permanent link
Cite this page
Languages
العربية
Azərbaycan
Aragonés
Беларуская
Català
Česky
Dansk
Deutsch
Eesti
Español
Français
हिन्दी
한국어
Hrvatski
Íslenska
Italiano
Қазақша
Nederlands
日本語
Norsk (bokmål)
Norsk (nynorsk)
Português
Română
Русский
Simple English
Srpskohrvatski / Српскохрватски
Suomi
Svenska
Tiếng Việt
中文
This page was last modified on 19 November 2009 at 17:06. Text is available under the Creative Commons Attribution-ShareAlike License; additional terms may apply. See Terms of Use for details.
Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization.Contact us Privacy policy About Wikipedia Disclaimers
Support Wikipedia today. $0.9M USD$7.5M USDDonate Now[Hide][Show]Wikipedia Forever Our shared knowledge. Our shared treasure. Help us protect it. [Show]Wikipedia Forever Our shared knowledge. Our shared treasure. Help us protect it. Tidal power
From Wikipedia, the free encyclopedia
Jump to: navigation, search
The world's first commercial axial turbine [3] tidal stream generator — SeaGen — in Strangford Lough. The strong wake shows the power in the tidal current.Renewable energy
Biofuel
Biomass
Geothermal
Hydroelectricity
Solar energy
Tidal power
Wave power
Wind power
v • d • e
Tidal power, sometimes called tidal energy, is a form of hydropower that converts the energy of tides into electricity or other useful forms of power.
Although not yet widely used, tidal power has potential for future electricity generation. Tides are more predictable than wind energy and solar power. Historically, tide mills have been used, both in Europe and on the Atlantic coast of North America. The earliest occurrences date from the Middle Ages, or even from Roman times.[1][2]
Contents [hide]
1 Generation of tidal energy
2 Categories of tidal power
3 Tidal stream generators
3.1 Engineering approaches
3.1.1 Axial Turbines
3.1.2 Vertical and horizontal axis crossflow turbines
3.1.3 Oscillating devices
3.1.4 Venturi effect
3.2 Commercial plans
3.3 Energy calculations
3.4 Potential sites
4 Barrage tidal power
4.1 Ebb generation
4.2 Flood generation
4.3 Pumping
4.4 Two-basin schemes
4.5 Environmental impact
4.5.1 Turbidity
4.5.2 Tidal fences and turbines
4.5.3 Salinity
4.5.4 Sediment movements
4.5.5 Fish
4.6 Energy calculations
4.6.1 Example calculation of tidal power generation
4.7 Economics
5 Mathematical modeling of tidal schemes
6 Global environmental impact
7 Operating tidal power schemes
8 Tidal power schemes being considered
9 See also
10 References
11 Notes
12 External links
[edit] Generation of tidal energy
Main articles: Tide and Tidal acceleration
Tidal power is the only form of energy which derives directly from the relative motions of the Earth–Moon system, and to a lesser extent from the Earth–Sun system. The tidal forces produced by the Moon and Sun, in combination with Earth's rotation, are responsible for the generation of the tides. Other sources of energy originate directly or indirectly from the Sun, including fossil fuels, conventional hydroelectric, wind, biofuels, wave power and solar. Nuclear is derived using radioactive material from the Earth, geothermal power uses the Earth's internal heat which comes from a combination of residual heat from planetary accretion (about 20%) and heat produced through radioactive decay (80%).[3]
Variation of tides over a dayTidal energy is generated by the relative motion of the Earth, Sun and the Moon, which interact via gravitational forces. Periodic changes of water levels, and associated tidal currents, are due to the gravitational attraction by the Sun and Moon. The magnitude of the tide at a location is the result of the changing positions of the Moon and Sun relative to the Earth, the effects of Earth rotation, and the local shape of the sea floor and coastlines.
Because the Earth's tides are caused by the tidal forces due to gravitational interaction with the Moon and Sun, and the Earth's rotation, tidal power is practically inexhaustible and classified as a renewable energy source.
A tidal energy generator uses this phenomenon to generate energy. The stronger the tide, either in water level height or tidal current velocities, the greater the potential for tidal energy generation.
Tidal movement causes a continual loss of mechanical energy in the Earth–Moon system due to pumping of water through the natural restrictions around coastlines, and due to viscous dissipation at the seabed and in turbulence. This loss of energy has caused the rotation of the Earth to slow in the 4.5 billion years since formation. During the last 620 million years the period of rotation has increased from 21.9 hours to the 24 hours[4] we see now; in this period the Earth has lost 17% of its rotational energy. While tidal power may take additional energy from the system, increasing the rate of slowdown, the effect would be noticeable over millions of years only, thus being negligible.
[edit] Categories of tidal power
Tidal power can be classified into three main types:
Tidal stream systems make use of the kinetic energy of moving water to power turbines, in a similar way to windmills that use moving air. This method is gaining in popularity because of the lower cost and lower ecological impact compared to barrages.
Barrages make use of the potential energy in the difference in height (or head) between high and low tides. Barrages are essentially dams across the full width of a tidal estuary, and suffer from very high civil infrastructure costs, a worldwide shortage of viable sites, and environmental issues.
Tidal lagoons, are similar to barrages, but can be constructed as self contained structures, not fully across an estuary, and are claimed to incur much lower cost and impact overall. Furthermore they can be configured to generate continuously which is not the case with barrages.
Modern advances in turbine technology may eventually see large amounts of power generated from the ocean, especially tidal currents using the tidal stream designs but also from the major thermal current systems such as the Gulf Stream, which is covered by the more general term marine current power. Tidal stream turbines may be arrayed in high-velocity areas where natural tidal current flows are concentrated such as the west and east coasts of Canada, the Strait of Gibraltar, the Bosporus, and numerous sites in Southeast Asia and Australia. Such flows occur almost anywhere where there are entrances to bays and rivers, or between land masses where water currents are concentrated.
[edit] Tidal stream generators
A relatively new technology, though first conceived in the 1970s during the oil crisis[5], tidal stream generators draw energy from currents in much the same way as wind turbines. The higher density of water, 800 times the density of air, means that a single generator can provide significant power at low tidal flow velocities (compared with wind speed).[6] Given that power varies with the density of medium and the cube of velocity, it is simple to see that water speeds of nearly one-tenth of the speed of wind provide the same power for the same size of turbine system. However this limits the application in practice to places where the tide moves at speeds of at least 2 knots (1m/s) even close to neap tides.
Since tidal stream generators are an immature technology (no commercial scale production facilities are yet routinely supplying power), no standard technology has yet emerged as the clear winner, but a large variety of designs are being experimented with, some very close to large scale deployment. Several prototypes have shown promise with many companies making bold claims, some of which are yet to be independently verified, but they have not operated commercially for extended periods to establish performances and rates of return on investments.
[edit] Engineering approaches
The European Marine Energy Centre[7] categorises them under four heads although a number of other approaches are also being tried.
[edit] Axial Turbines
Evopod - A semi-submerged floating approach tested in Strangford Lough.These are close in concept to traditional windmills operating under the sea and have the most prototypes currently operating. These include:
Kvalsund, south of Hammerfest, Norway.[8] Although still a prototype, a turbine with a reported capacity of 300 kW was connected to the grid on 13 November 2003.
A 300 kW Periodflow marine current propeller type turbine — Seaflow — was installed by Marine Current Turbines off the coast of Lynmouth, Devon, England, in 2003.[9] The 11m diameter turbine generator was fitted to a steel pile which was driven into the seabed. As a prototype, it was connected to a dump load, not to the grid.
Since April 2007 Verdant Power[10] has been running a prototype project in the East River between Queens and Roosevelt Island in New York City; it was the first major tidal-power project in the United States.[11] The strong currents pose challenges to the design: the blades of the 2006 and 2007 prototypes broke off, and new reinforced turbines were installed in September 2008.[12][13]
Following the Seaflow trial, a fullsize prototype, called SeaGen, was installed by Marine Current Turbines in Strangford Lough in Northern Ireland in April 2008. The turbine began to generate at full power of just over 1.2 MW in December 2008[14] and was reported to have fed 150 kW into the grid for the first time on 17 July 2008.[15] It is currently the only commercial scale device to have been installed anywhere in the world.[16] SeaGen is made up of two axial flow rotors, each of which drive a generator. The turbines are capable of generating electricity on both the ebb and flood tides because the rotor blades can pitch through 180˚.[17]
OpenHydro,[18] an Irish company exploiting the Open-Centre Turbine developed in the U.S., has a prototype being tested at the European Marine Energy Centre (EMEC), in Orkney, Scotland.
A prototype semi-submerged floating tethered tidal turbine called Evopod has been tested since June 2008[19] in Strangford Lough, Northern Ireland at 1/10th scale. The company developing it is called Ocean Flow Energy Ltd[20], and they are based in the UK. The advanced hull form maintains optimum heading into the tidal stream and it is designed to operate in the peak flow of the water column.
[edit] Vertical and horizontal axis crossflow turbines
Invented by Georges Darreius in 1923 and Patented in 1929, these are crossflow turbines that can be deployed either vertically or horizontally.
The Gorlov turbine[21] is a variant of the Darrieus design featuring a helical design which is being commercially piloted on a large scale in S. Korea,[22] starting with a 1MW plant that started in May 2009[23] and expanding to 90MW by 2013. Neptune Renewable Energy has developed Proteus[24] which uses a barrage of vertical axis crossflow turbines for use mainly in estuaries.
In late April 2008, Ocean Renewable Power Company, LLC (ORPC) [4] successfully completed the testing of its proprietary turbine-generator unit (TGU) prototype at ORPC’s Cobscook Bay and Western Passage tidal sites near Eastport, Maine.[25] The TGU is the core of the OCGen technology and utilizes advanced design cross-flow (ADCF) turbines to drive a permanent magnet generator located between the turbines and mounted on the same shaft. ORPC has developed TGU designs that can be used for generating power from river, tidal and deep water ocean currents.
[edit] Oscillating devices
Oscillating devices do not have a rotating component, instead making use of aerofoil sections which are pushed sideways by the flow. Oscillating stream power extraction was proven with the omni- or bi-directional Wing'd Pump windmill.[26] During 2003 a 150 kW oscillating hydroplane device, the Stingray, was tested off the Scottish coast.[27] The Stingray uses hydrofoils to create oscillation, which allows it to create hydraulic power. This hydraulic power is then used to power a hydraulic motor, which then turns a generator.[28]
[edit] Venturi effect
Further information: Venturi effect
This uses a shroud to increase the flow rate through the turbine. These can be mounted horizontally or vertically.
The Australian company Tidal Energy Pty Ltd undertook successful commercial trials of highly efficient shrouded tidal turbines on the Gold Coast, Queensland in 2002. Tidal Energy has commenced a rollout of their shrouded turbine for a remote Australian community in northern Australia where there are some of the fastest flows ever recorded (11 m/s, 21 knots) – two small turbines will provide 3.5 MW. Another larger 5 meter diameter turbine, capable of 800 kW in 4 m/s of flow, is planned for deployment as a tidal powered desalination showcase near Brisbane Australia in October 2008. Another device, the Hydro Venturi, is to be tested in San Francisco Bay.[29]
Trials in the Strait of Messina, Italy, started in 2001 of the Kobold concept.[30]
[edit] Commercial plans
RWE's npower announced that it is in partnership with Marine Current Turbines to build a tidal farm of SeaGen turbines off the coast of Anglesey in Wales.[31]
In November 2007, British company Lunar Energy announced that, in conjunction with E.ON, they would be building the world's first tidal energy farm off the coast of Pembrokshire in Wales. It will be the world's first deep-sea tidal-energy farm and will provide electricity for 5,000 homes. Eight underwater turbines, each 25 metres long and 15 metres high, are to be installed on the sea bottom off St David's peninsula. Construction is due to start in the summer of 2008 and the proposed tidal energy turbines, described as "a wind farm under the sea", should be operational by 2010.
British Columbia Tidal Energy Corp. plans to deploy at least three 1.2 MW turbines in the Campbell River or in the surrounding coastline of British Columbia by 2009.[32]
An organisation named Alderney Renewable Energy Ltd is planning to use tidal turbines to extract power from the notoriously strong tidal races around Alderney in the Channel Islands. It is estimated that up to 3GW could be extracted. This would not only supply the island's needs but also leave a considerable surplus for export.[33]
Nova Scotia Power has selected OpenHydro's turbine for a tidal energy demonstration project in the Bay of Fundy, Nova Scotia, Canada and Alderney Renewable Energy Ltd for the supply of tidal turbines in the Channel Islands. Open Hydro
[edit] Energy calculations
Various turbine designs have varying efficiencies and therefore varying power output. If the efficiency of the turbine "Cp" is known the equation below can be used to determine the power output.
The energy available from these kinetic systems can be expressed as:
P = Cp x 0.5 x ρ x A x V³[34]
where:
Cp is the turbine coefficient of performance
P = the power generated (in watts)
ρ = the density of the water (seawater is 1025 kg/m³)
A = the sweep area of the turbine (in m²)
V³ = the velocity of the flow cubed (i.e. V x V x V)
Relative to an open turbine in free stream, shrouded turbines are capable of as much as 3 to 4 times the power of the same rotor in open flow, depending on the geometry of the shroud.[34] However, to measure the efficiency, one must compare the benefits of a larger rotor with the benefits of the shroud.
[edit] Potential sites
As with wind power, selection of location is critical for the tidal turbine. Tidal stream systems need to be located in areas with fast currents where natural flows are concentrated between obstructions, for example at the entrances to bays and rivers, around rocky points, headlands, or between islands or other land masses. The following potential sites are under serious consideration:
Pembrokeshire in Wales[35]
River Severn between Wales and England[36]
Cook Strait in New Zealand[37]
Kaipara Harbour in New Zealand[38]
Bay of Fundy[39] in Canada.
East River[40][41] in the USA
Golden Gate in the San Francisco Bay[42]
Piscataqua River in New Hampshire[43]
The Race of Alderney and The Swinge in the Channel Islands[33]
[edit] Barrage tidal power
Rance tidal power plant
An artistic impression of a tidal barrage, including embankments, a ship lock and caissons housing a sluice and two turbines.With only a few operating plants globally, a large 240 MW plant on the Rance River, and two small plants, one on the Bay of Fundy and the other across a tiny inlet in Kislaya Guba, Russia), and a suggested Severn barrage across the River Severn, from Brean Down in England to Lavernock Point near Cardiff in Wales, the barrage method of extracting tidal energy involves building a barrage across a bay or river, as in the case of the Rance tidal power plant in France. Turbines installed in the barrage wall generate power as water flows in and out of the estuary basin, bay, or river. These systems are similar to a hydro dam that produces Static Head or pressure head (a height of water pressure). When the water level outside of the basin or lagoon changes relative to the water level inside, the turbines are able to produce power. The largest such installation has been working on the Rance river, France, since 1966.
The basic elements of a barrage are caissons, embankments, sluices, turbines, and ship locks. Sluices, turbines, and ship locks are housed in caissons (very large concrete blocks). Embankments seal a basin where it is not sealed by caissons.
The sluice gates applicable to tidal power are the flap gate, vertical rising gate, radial gate, and rising sector.
Barrage systems are affected by problems of high civil infrastructure costs associated with what is in effect a dam being placed across estuarine systems, and the environmental problems associated with changing a large ecosystem.
Potentials for UK barrages are here. [44]
[edit] Ebb generation
The basin is filled through the sluices until high tide. Then the sluice gates are closed. (At this stage there may be "Pumping" to raise the level further). The turbine gates are kept closed until the sea level falls to create sufficient head across the barrage, and then are opened so that the turbines generate until the head is again low. Then the sluices are opened, turbines disconnected and the basin is filled again. The cycle repeats itself. Ebb generation (also known as outflow generation) takes its name because generation occurs as the tide changes tidal direction.
[edit] Flood generation
The basin is filled through the turbines, which generate at tide flood. This is generally much less efficient than ebb generation, because the volume contained in the upper half of the basin (which is where ebb generation operates) is greater than the volume of the lower half (filled first during flood generation). Therefore the available level difference — important for the turbine power produced — between the basin side and the sea side of the barrage, reduces more quickly than it would in ebb generation. Rivers flowing into the basin may further reduce the energy potential, instead of enhancing it as in ebb generation. Which of course is not a problem with the "lagoon" model, without river inflow.
[edit] Pumping
Turbines are able to be powered in reverse by excess energy in the grid to increase the water level in the basin at high tide (for ebb generation). This energy is more than returned during generation, because power output is strongly related to the head. If water is raised 2 ft (61 cm) by pumping on a high tide of 10 ft (3 m), this will have been raised by 12 ft (3.7 m) at low tide. The cost of a 2 ft rise is returned by the benefits of a 12 ft rise. This is since the correlation between the potential energy is not a linear relationship, rather, is related by the square of the tidal height variation.
[edit] Two-basin schemes
Another form of energy barrage configuration is that of the dual basin type. With two basins, one is filled at high tide and the other is emptied at low tide. Turbines are placed between the basins. Two-basin schemes offer advantages over normal schemes in that generation time can be adjusted with high flexibility and it is also possible to generate almost continuously. In normal estuarine situations, however, two-basin schemes are very expensive to construct due to the cost of the extra length of barrage. There are some favourable geographies, however, which are well suited to this type of scheme.
[edit] Environmental impact
The placement of a barrage into an estuary has a considerable effect on the water inside the basin and on the ecosystem. Many governments have been reluctant in recent times to grant approval for tidal barrages. Through research conducted on tidal plants, it has been found that tidal barrages constructed at the mouths of estuaries pose similar environmental threats as large dams. The construction of large tidal plants alters the flow of saltwater in and out of estuaries, which changes the hydrology and salinity and possibly negatively affects the marine mammals that use the estuaries as their habitat [45] The La Rance plant, off the Brittany coast of northern France, was the first and largest tidal barrage plant in the world. It is also the only site where a full-scale evaluation of the ecological impact of a tidal power system, operating for 20 years, has been made [46]
French researchers found that the isolation of the estuary during the construction phases of the tidal barrage was detrimental to flora and fauna, however; after ten years, there has been a “variable degree of biological adjustment to the new environmental conditions” [46]
Some species lost their habitat due to La Rance’s construction, but other species colonized the abandoned space, which caused a shift in diversity. Also as a result of the construction, sandbanks disappeared, the beach of St. Servan was badly damaged and high-speed currents have developed near sluices, which are water channels controlled by gates [47]
[edit] Turbidity
Turbidity (the amount of matter in suspension in the water) decreases as a result of smaller volume of water being exchanged between the basin and the sea. This lets light from the Sun to penetrate the water further, improving conditions for the phytoplankton. The changes propagate up the food chain, causing a general change in the ecosystem.
[edit] Tidal fences and turbines
Tidal fences and turbines can have varying environmental impacts depending on whether or not fences and turbines are constructed with regard to the environment. The main environmental impact of turbines is their impact on fish. If the turbines are moving slowly enough, such as low velocities of 25-50 rpm, fish kill is minimalized and silt and other nutrients are able to flow through the structures [45] For example, a 20 kW tidal turbine prototype built in the St. Lawrence Seaway in 1983 reported no fish kills [45] Tidal fences block off channels, which makes it difficult for fish and wildlife to migrate through those channels. In order to reduce fish kill, fences could be engineered so that the spaces between the caisson wall and the rotor foil are large enough to allow fish to pass through [45] Larger marine mammals such as seals or dolphins can be protected from the turbines by fences or a sonar sensor auto-breaking system that automatically shuts the turbines down when marine mammals are detected [45] Overall, many researches have argued that while tidal barrages pose environmental threats, tidal fences and tidal turbines, if constructed properly, are likely to be more environmentally benign. Unlike barrages, tidal fences and turbines do not block channels or estuarine mouths, interrupt fish migration or alter hydrology, thus, these options offer energy generating capacity without dire environmental impacts [45]
[edit] Salinity
As a result of less water exchange with the sea, the average salinity inside the basin decreases, also affecting the ecosystem.[citation needed] "Tidal Lagoons" do not suffer from this problem.[citation needed]
[edit] Sediment movements
Estuaries often have high volume of sediments moving through them, from the rivers to the sea. The introduction of a barrage into an estuary may result in sediment accumulation within the barrage, affecting the ecosystem and also the operation of the barrage.
[edit] Fish
Fish may move through sluices safely, but when these are closed, fish will seek out turbines and attempt to swim through them. Also, some fish will be unable to escape the water speed near a turbine and will be sucked through. Even with the most fish-friendly turbine design, fish mortality per pass is approximately 15%[citation needed] (from pressure drop, contact with blades, cavitation, etc.). Alternative passage technologies (fish ladders, fish lifts, fish escalators etc.) have so far failed to solve this problem for tidal barrages, either offering extremely expensive solutions, or ones which are used by a small fraction of fish only. Research in sonic guidance of fish is ongoing.[citation needed] The Open-Centre turbine reduces this problem allowing fish to pass through the open centre of the turbine.
Recently a run of the river type turbine has been developed in France. This is a very large slow rotating Kaplan type turbine mounted on an angle. Testing for fish mortality has indicated fish mortality figures to be less than 5%. This concept also seems very suitable for adaption to marine current/tidal turbines.[48]
[edit] Energy calculations
The energy available from a barrage is dependent on the volume of water. The potential energy contained in a volume of water is:[49]
where:
h is the vertical tidal range,
A is the horizontal area of the barrage basin,
ρ is the density of water = 1025 kg per cubic meter (seawater varies between 1021 and 1030 kg per cubic meter) and
g is the acceleration due to the Earth's gravity = 9.81 meters per second squared.
The factor half is due to the fact, that as the basin flows empty through the turbines, the hydraulic head over the dam reduces. The maximum head is only available at the moment of low water, assuming the high water level is still present in the basin.
[edit] Example calculation of tidal power generation
Assumptions:
Let us assume that the tidal range of tide at a particular place is 32 feet = 10 m (approx)
The surface of the tidal energy harnessing plant is 9 km² (3 km × 3 km)= 3000 m × 3000 m = 9 × 106 m2
Density of sea water = 1025.18 kg/m3
Mass of the sea water = volume of sea water × density of sea water
= (area × tidal range) of water × mass density
= (9 × 106 m2 × 10 m) × 1025.18 kg/m3
= 92 × 109 kg (approx)
Potential energy content of the water in the basin at high tide = ½ × area × density × gravitational acceleration × tidal range squared
= ½ × 9 × 106 m2 × 1025 kg/m3 × 9.81 m/s2 × (10 m)2
=4.5 × 1012 J (approx)
Now we have 2 high tides and 2 low tides every day. At low tide the potential energy is zero.
Therefore the total energy potential per day = Energy for a single high tide × 2
= 4.5 × 1012 J × 2
= 9 × 1012 J
Therefore, the mean power generation potential = Energy generation potential / time in 1 day
= 9 × 1012 J / 86400 s
= 104 MW
Assuming the power conversion efficiency to be 30%: The daily-average power generated = 104 MW * 30% / 100%
= 31 MW (approx)
A barrage is best placed in a location with very high-amplitude tides. Suitable locations are found in Russia, USA, Canada, Australia, Korea, the UK. Amplitudes of up to 17 m (56 ft) occur for example in the Bay of Fundy, where tidal resonance amplifies the tidal range.
[edit] Economics
Tidal barrage power schemes have a high capital cost and a very low running cost. As a result, a tidal power scheme may not produce returns for many years, and investors may be reluctant to participate in such projects.
Governments may be able to finance tidal barrage power, but many are unwilling to do so also due to the lag time before investment return and the high irreversible commitment. For example the energy policy of the United Kingdom[50] recognizes the role of tidal energy and expresses the need for local councils to understand the broader national goals of renewable energy in approving tidal projects. The UK government itself appreciates the technical viability and siting options available, but has failed to provide meaningful incentives to move these goals forward.
[edit] Mathematical modeling of tidal schemes
In mathematical modeling of a scheme design, the basin is broken into segments, each maintaining its own set of variables. Time is advanced in steps. Every step, neighbouring segments influence each other and variables are updated.
The simplest type of model is the flat estuary model, in which the whole basin is represented by one segment. The surface of the basin is assumed to be flat, hence the name. This model gives rough results and is used to compare many designs at the start of the design process.
In these models, the basin is broken into large segments (1D), squares (2D) or cubes (3D). The complexity and accuracy increases with dimension.
Mathematical modeling produces quantitative information for a range of parameters, including:
Water levels (during operation, construction, extreme conditions, etc.)
Currents
Waves
Power output
Turbidity
Salinity
Sediment movements
[edit] Global environmental impact
A tidal power scheme is a long-term source of electricity. A proposal for the Severn Barrage, if built, has been projected to save 18 million tonnes of coal per year of operation. This decreases the output of greenhouse gases into the atmosphere.
If fossil fuel resources decline during the 21st century, as predicted by Hubbert peak theory, tidal power is one of the alternative sources of energy that will need to be developed to satisfy the human demand for energy.
[edit] Operating tidal power schemes
The first tidal power station was the Rance tidal power plant built over a period of 6 years from 1960 to 1966 at La Rance, France.[51] It has 240 MW installed capacity.
The first tidal power site in North America is the Annapolis Royal Generating Station, Annapolis Royal, Nova Scotia, which opened in 1984 on an inlet of the Bay of Fundy.[52] It has 18 MW installed capacity.
The first in-stream tidal current generator in North America (Race Rocks Tidal Power Demonstration Project) was installed at Race Rocks on southern Vancouver Island in September 2006.[53][54] The next phase in the development of this tidal current generator will be in Nova Scotia.[55]
A small project was built by the Soviet Union at Kislaya Guba on the Barents Sea. It has 0.5 MW installed capacity. In 2006 it was upgraded with 1.2MW experimental advanced orthogonal turbine.
Jindo Uldolmok Tidal Power Plant in South Korea is a tidal stream generation scheme planned to be expanded progressively to 90 MW of capacity by 2013. The first 1 MW was installed in May 2009. [56]
1.2 MW SeaGen system became operational in late 2008 on Strangford Lough in Northern Ireland. [57]
[edit] Tidal power schemes being considered
In the table, "-" indicates missing information, "?" indicates information which has not been decided
Country Place Mean tidal range (m) Area of basin (km²) Maximum capacity (MW)
United Kingdom and Channel Islands River Severn 7.8 450 8640
Russia[58] Penzhinskaya Bay[59][60] 6.0 20,500 87,000
A 12MW project at Kislaya Guba in Russia with orthogonal turbines is under construction.
254 MW Sihwa Lake Tidal Power Plant in South Korea is under construction and planned to be completed by November 2009.[61]
China is developing a tidal lagoon near the mouth of the Yalu River.[62]
[edit] See also
Energy portal
Sustainable development portal
Category:Energy by country
Run-of-the-river hydroelectricity
Damless hydro
Marine current power
Stream energy
Ocean energy
Thermal energy
Wave power
World energy resources and consumption
[edit] References
Baker, A. C. 1991, Tidal power, Peter Peregrinus Ltd., London.
Baker, G. C., Wilson E. M., Miller, H., Gibson, R. A. & Ball, M., 1980. "The Annapolis tidal power pilot project", in Waterpower '79 Proceedings, ed. Anon, U.S. Government Printing Office, Washington, pp 550–559.
Hammons, T. J. 1993, "Tidal power", Proceedings of the IEEE, [Online], v81, n3, pp 419–433. Available from: IEEE/IEEE Xplore. [July 26, 2004].
Lecomber, R. 1979, "The evaluation of tidal power projects", in Tidal Power and Estuary Management, eds. Severn, R. T., Dineley, D. L. & Hawker, L. E., Henry Ling Ltd., Dorchester, pp 31–39.
[edit] Notes
^ Spain, Rob: "A possible Roman Tide Mill", Paper submitted to the Kent Archaeological Society
^ Minchinton, W. E. (October 1979). "Early Tide Mills: Some Problems". Technology and Culture 20 (4): 777–786. doi:10.2307/3103639.
^ Turcotte, D. L.; Schubert, G. (2002). "4". Geodynamics (2 ed.). Cambridge, England, UK: Cambridge University Press. pp. 136–137. ISBN 978-0-521-66624-4.
'^ George E. Williams. "Geological constraints on the Precambrian history of Earth's rotation and the Moon's orbit". Reviews of Geophysics '38 (2000), 37-60.
^ Jones, Anthony T., and Adam Westwood. "Power from the oceans: wind energy industries are growing, and as we look for alternative power sources, the growth potential is through the roof. Two industry watchers take a look at generating energy from wind and wave action and the potential to alter." The Futurist 39.1 (2005): 37(5). GALE Expanded Academic ASAP. Web. 8 Oct. 2009.
^ "Surfing Energy's New Wave: FOR CENTURIES, PEOPLE HAVE DREAMED OF HARNESSING THE POWER OF OCEAN TIDES. HAS A COMPANY IN WALES MADE THE DREAM COME TRUE?" Time International 16 June 2003: 52+. http://www.time.com/time/magazine/article/0,9171,457348,00.html
^ EMEC. "Tidal Energy Devices". http://www.emec.org.uk/tidal_devices.htm. Retrieved 5 October 2008.
^ First power station to harness Moon opens - September 22, 2003 - New Scientist
^ REUK: "Read about the first open-sea tidal turbine generator off Lynmouth, Devon"
^ Verdant Power
^ MIT Technology Review, April 2007 Accessed August 24, 2008]
^ Robin Shulman (September 20, 2008). "N.Y. Tests Turbines to Produce Power. City Taps Current Of the East River". Washington Post. http://www.washingtonpost.com/wp-dyn/content/article/2008/09/19/AR2008091903729.html. Retrieved 2008-10-09.
^ Kate Galbraith (September 22, 2008). "Power From the Restless Sea Stirs the Imagination". New York Times. http://www.nytimes.com/2008/09/23/business/23tidal.html?em. Retrieved 2008-10-09.
^ http://www.marineturbines.com/3/news/
^ First connection to the grid
^ · Sea Generation Tidal Turbine
^ Marine Current Turbines. "Technology." Marine Current Turbines. Marine Current Turbines, n.d. Web. 5 Oct. 2009.
^ OpenHydro
^ [1] Ocean Flow Energy Ltd annouce the start of their testing in Strangford Lough
^ Ocean Flow Energy company website
^ Gorlov Turbine
^ Gorlov Turbines in Koreas
^ "South Korea starts up, to expand 1-MW Jindo Uldolmok tidal project". Hydro World. 2009. http://www.hydroworld.com/index/display/article-display/2336952618/articles/hrhrw/hydroindustrynews/ocean-tidal-streampower/south-korea_starts.html.
^ Proteus
^ "Tide is slowly rising in interest in ocean power". Mass High Tech: The Journal of New England Technology. August 1, 2008. http://www.masshightech.com/stories/2008/07/28/weekly9-Tide-is-slowly-rising-in-interest-in-ocean-power.html/. Retrieved 2008-10-11.
^ Wing'd Pump Windmill
^ Stingray
^ Jones, Anthony T., and Adam Westwood. "Power from the oceans: wind energy industries are growing, and as we look for alternative power sources, the growth potential is through the roof. Two industry watchers take a look at generating energy from wind and wave action and the potential to alter." The Futurist 39.1 (2005): 37(5). GALE Expanded Academic ASAP. Web. 8 Oct. 2009.
^ San Francisco Bay Guardian News
^ A.D.A.Group
^ RWE plans 10.5 MW sea current power plant off Welsh coast - Forbes.com
^ Tidal Power Coming to West Coast of Canada
^ a b Alderney Renewable Energy Ltd
^ a b http://www.cyberiad.net/library/pdf/bk_tidal_paper25apr06.pdf tidal paper on cyberiad.net
^ Builder & Engineer - Pembrokeshire tidal barrage moves forward
^ Severn balancing act
^ NZ: Chance to turn the tide of power supply | EnergyBulletin.net | Peak Oil News Clearinghouse
^ Harnessing the power of the sea Energy NZ, Vol 1, No 1, Winter 2007.
^ Bay of Fundy to get three test turbines | Cleantech.com
^ Shulman, Robin (September 20, 2008). "N.Y. Tests Turbines to Produce Power". The Washington Post. ISSN 0740-5421. http://www.washingtonpost.com/wp-dyn/content/article/2008/09/19/AR2008091903729.html?hpid=topnews&sub=AR. Retrieved 2008-09-20.
^ Verdant Power
^ http://deanzaemtp.googlepages.com/PGEbacksnewstudyofbaystidalpower.pdf
^ Tidal power from Piscataqua River?
^ http://www.claverton-energy.com/tidal-barrage-potential-in-england.html
^ a b c d e f Pelc, Robin and Fujita, Rob. Renewable energy from the ocean.
^ a b Retiere, C. Tidal power and aquatic environment of La Rance.
^ Charlier, Roger. Forty candles for the Rance River TPP tides provide renewable and sustainable power generation
^ VLH TURBINE
^ Lamb, H. (1994). Hydrodynamics (6th edition ed.). Cambridge University Press. ISBN 9780521458689. §174, p. 260.
^ [2] (see for example key principles 4 and 6 within Planning Policy Statement 22)
^ L'Usine marémotrice de la Rance
^ Nova Scotia Power - Environment - Green Power- Tidal
^ Race Rocks Demonstration Project
^ Tidal Energy, Ocean Energy
^ Information for media inquiries
^ Korea's first tidal power plant built in Uldolmok, Jindo
^ http://news.bbc.co.uk/2/hi/uk_news/northern_ireland/7790494.stm
^ http://www.elektropages.ru/article/4_2006_ELEKTRO.html
^ Russian power plants soon to utilize tidal energy :: Russia-InfoCentre
^ http://www.severnestuary.net/sep/pdfs/managingtidalchangeprojectreport-phase1final.pdf
^ Sihwa Lake Tidal Power Plant targets completion by late 2009
^ China Endorses 300 MW Ocean Energy Project
[edit] External links
Wikimedia Commons has media related to: Tidal power
Marine and Hydrokinetic Technology Database The U.S. Department of Energy’s Marine and Hydrokinetic Technology Database provides up-to-date information on marine and hydrokinetic renewable energy, both in the U.S. and around the world.
Severn Estuary Partnership: Tidal Power Resource Page
Location of Potential Tidal Stream Power sites in the UK
University of Strathclyde ESRU-- Detailed analysis of marine energy resource, current energy capture technology appraisal and environmental impact outline
Coastal Research - Foreland Point Tidal Turbine and warnings on proposed Severn Barrage
Sustainable Development Commission - Report looking at 'Tidal Power in the UK', including proposals for a Severn barrage
World Energy Council - Report on Tidal Energy
Wave and Tidal Energy News
How electricity is produced using Tidal Energy ?
[hide]v • d • eOcean energy
Wave power Australia • New Zealand
Tidal power New Zealand •Annapolis Royal Generating Station
Osmotic power
Other Marine current power • Ocean engineering • Ocean thermal energy conversion • Pelamis wave energy converter • Wind power (offshore) • Wave farm
Portals: Energy • Sustainable development
Retrieved from "http://en.wikipedia.org/wiki/Tidal_power"
Categories: Energy from oceans and water | Tidal power | Coastal construction | Tides
Hidden categories: All articles with unsourced statements | Articles with unsourced statements from August 2008 | Articles with unsourced statements from August 2007 | Articles with unsourced statements from February 2008
ViewsArticle Discussion Edit this page History Personal toolsTry Beta Log in / create account Navigation
Main page
Contents
Featured content
Current events
Random article
Search
Interaction
About Wikipedia
Community portal
Recent changes
Contact Wikipedia
Donate to Wikipedia
Help
Toolbox
What links here
Related changes
Upload file
Special pages
Printable version
Permanent link
Cite this page
Languages
العربية
Azərbaycan
Aragonés
Беларуская
Català
Česky
Dansk
Deutsch
Eesti
Español
Français
हिन्दी
한국어
Hrvatski
Íslenska
Italiano
Қазақша
Nederlands
日本語
Norsk (bokmål)
Norsk (nynorsk)
Português
Română
Русский
Simple English
Srpskohrvatski / Српскохрватски
Suomi
Svenska
Tiếng Việt
中文
This page was last modified on 19 November 2009 at 17:06. Text is available under the Creative Commons Attribution-ShareAlike License; additional terms may apply. See Terms of Use for details.
Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization.Contact us Privacy policy About Wikipedia Disclaimers
Subscribe to:
Posts (Atom)