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U.S. Wind Resource Map - U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy
There is no argument against the fact that wind power is a clean, renewable power source (exclusive for electricity generation), and domestically produced. However, it is an inconsistent power source: the occurrence of wind is intermittent and the strength of the wind is variable, which is really the exact opposite of what an electrical grid and its customers require: predictable and consistent power that can be scheduled. Many nations are adding wind turbine capacity however only a percentage of that capacity is producing electricity at any given time. This has resulted in a problem that wind derived electricity cannot be scheduled or dispatched with any predictability on any given day. Rather, wind derived electricity often becomes available at times when the grid's power sources and base load demand are already balanced.
Wind forecasting has become very important in determining the location and size of a wind farm. MCP analysis (measure-correlate-predict) is used to assess whether a site is appropriate through methods and algorithms that utilize wind data from one or a number of potential wind farm sites and correlate them with local historical observation / reference sites. The methods include a linear regression MCP method (traditional linear regression analysis). Weibull Scale (manipulates appropriate Weibull distributions), wind index MCP (monthly averages), and a matrix method (wind speed and wind direction distribution). Further adjustments may have to be made due the differences between the historical observation point and the actual proposed location of the wind farm site (wind is affected by the shape and terrain of the local landscape, and the elevation of observation point compared to the elevation of the wind turbine). Ideally, the project manager will erect a meteorological tower at the location of the proposed site and measure winds for a minimum of one year.
The credit analysis of determining the feasability of financing a wind farm project needs to include the calculation of conservative wind, which is an annual energy yield prediction based on the average wind speed forecast with a 90.0% probability, also referred to as P90 (90% confidence range). The P90 needs to be within a specific percentage of the average, usually 10% to 12%. Other important considerations include performance warranties, and warranties in terms of losses in the energy production.
The wind-powered electricity generating device is a turbine located on top of a steel tower (which also referred to as a mast). The tower needs to be of a sufficient height above any other nearby obstruction. The upper part of the wind turbine that sits on top of the mast is called the nacelle enclosure (also referred to as a gondola). The blades of the turbine are attached to a rotor hub, which is attached to a shaft that is mounted in the nacelle / gondola. The nacelle / gondola rotates on the mast, so that the turbine can always be optimally positioned with its nose to the wind (there are electic controls in the nacelle / gondola to control the direction / position). The gearbox, generator and transformer are all located in the nacelle / gondola.
The rotor blades / hub are attached to the rotor shaft. The rotor blades can tilt to catch more or less wind (there are electic controls in the nacelle / gondola to control the blade pitch position). The turbines are fitted with sensors that measure the wind force and direction to ensure the blades are always in the wind. The rotating movement of this shaft is accelerated in a gearbox. The gearbox, in turn, drives the generator. The generator is a kind of dynamo that converts the rotating movement into electricity (generator size is from 100 kilowatts to several megawatts). Within the turbine, a transformer further increases the voltage to enable long-distance transportation with minimum power loss. The generated electricity is transmitted though a wire that runs the length of the mast back down to the surface, which then connects to a regional transmission grid.
Source: U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy (EERE)
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Denmark has the largest percentage of national electricity generating capacity of any nation. Approximately 2,778 MW from land-based wind turbines and 632 MW from offshore-based turbines provide 3,436 MW / 24.1% of capacity and approximately 19.7% of actual electricity production. The national often generates electricity in excess of immediate demand, which is sold into the Nord Pool Spot market.
Germany increased installation since 2002 and wind-derived electricity generation now accounts for approximately 7.5% of capacity. However, the nation has had temporary surpluses of electricity such that wind farms had to actually pay grid operators to take surplus electricity and some consumers received a subsidy for utilizing the surplus.
The People's Republic of China is one of the fastest growing markets for wind turbine generated electricity. the nation is anticipated to install 18.0 Gigawatts of new wind generator capacity during 2010. The largest wind turbine manufacturer within China is Sinovel Wind Co.
The Energy Information Administration (EIA), U.S. Department of Energy estimated that in 2007 wind turbine generated electric power accounted for less than 1.0% of total power generation in the United States and accounted for only 1.3% of actual electricity produced in the United States in 2008 although the actual capacity is much higher due to the recent construction of wind farms. The U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, indicates that as of April 30, 2009, 28,635 MW of wind power had been installed across the United States. Texas had the highest capacity, 8,203 MW, followed by Iowa (2,862 MW), California (2,668 MW), Minnesota (1,802 MW), Washington (1,504 MW), Oregon (1,435 MW), New York (1,2274 MW), Colorado (1,068 MW), Kansas (1,021 MW)
Delmarva signed a power purchase agreement with Bluewater Wind for 10 cents per kilowatt hour from the offshore wind farm in Delaware (Mid-Atlantic Bight).
As indicated above, the construction of an offshore wind farm project is even more expensive than a land-based project, however the wind blows harder and more consistently offshore (the U.S. Department of Energy estimates that the cost of offshore infrastructure ranges from $2,400 to $5,000 per kW). An offshore turbine needs to either be located on a tower fastened to the sea floor or located on a tower fastened to a sunken concrete block sitting on the sea floor. This means that they are usually located within view from the coast line, which results in one of the major sources of opposition: asthetic detraction. There are floating alternatives (a tower with sufficient ballast design that is anchored to the ocean floor by cable, similar to the TLP / Tension Leg Platform design for some floating offshore oil rigs but on a much smaller scale) that are being developed, which means that an offshore project could be located out of sight from the shore line.
In the United States, and to a lesser extent around the world, the National Data Buoy Center provides recorded offshore wind
speed data. Select Recent Data or Historical Data, select a region, select a buoy, and then look for Wind Speed (WSPD) and / or Wind Gust (GST).
www.ndbc.noaa.gov/rmd.shtml
Small Wind Systems are towers / turbines erected to provide electricity to individual residential or commercial properties, or small businesses in a distributed generation design (source of electricity production located at the place of consumption). It can be one or more turbines, and the system produces 100 kW or less. These systems are located in urban and suburban areas thus are subject to local zoning ordaninces and utility grid-connected regulations. The cost per watt installed (price of system divided by the kW of the system; eaxample: $18,000 divided by 3,000 or 3 kW = $6.00 per watt installed) is comparable to installing photovoltaic solar panels. Thus, the calculation of conservative wind is essential in determining the selection of a small wind system. In the United States, the system should qualify for the federal 30.0% tax credit for individual filers / residential properties.
The most recently completed wind farm projects that are up and operating have brought some credibility to the industry, which has resulted in a steady decline in insurance and financing costs.
The wind as a source of power generation is unreliable and hard to harness. Peak demand for elelctricity is usually during day time hours and also increases during the summer months (as air conditioners are turned on). The wind tends to blow harder during the evening hours and winds increase during the winter months. The wind needs to blow hard enough, and steady enough, for large turbines to make (an optimal) 20 revolutions per minute (electricity can still be generated at less revolutions per minute). Unfortunately, that is normally not obtainable and wind turbine plants are usually producing below capacity. Although they can add to total output at any given time they cannot be relied upon to increase capacity during peak demand.
The U.S. Department of Energy estimates that the U.S. federal government goal of 20% of electricity supply (approximately 300 GW) being generated from wind turbine sources by the 2030 would require a 20% annual growth in installations for nearly a decade from 2006 through 2017 and then require maintaining that installation level through 2030. It is unclear whether there is sufficient capital (the DOE estimates an investment of $3.0 billion per year for the next 20 years) or a qualified and educated workforce to manufacture, install and maintain that type of investment. Similalry, there would also be related cost increases for steel, fiberglass, resins, adhesives and permanent magnets.
It is possible that just within 5 to 10 years that there could be a sufficient enough design or manufacturing breakthrough that would render today's wind turbine design as sub-standard.
The U.S. electrical transmission system will have to be substantially extended to reach prime locations for wind farm site installation, which tend to be remote locations far from population centers. Secondly, existing transmission systems with substantial wind-powered electricity injection would require upgraded capabilities for monitoring and managing load balance. In addition, there is some reluctance from existing utilities that own transmission infrastructure to allow interconnection of potentially large numbers of distributed generators owned and operated by non-utilities due to safety and reliability issues.
Price wise in the United States, electricity produced by an existing wind turbine is very inexpensive, especially when the U.S. tax credit is added on (price for electricity is quoted in cents per kilowatt hour). However, because of the low "capacity factor" of wind turbine generation (because the wind may not be blowing at the right moment the wind turbine may not be able to be relied upon at a critical moment nor is the turbine ever producing at full output) the price for wind generated electricity is actually priced lower compared to more reliable generation capacity from natural gas and coal-fired power generation plants. The decision to invest in a wind turbine plant must be measured against the future cost of natural gas as a power supply for electricity generation and / or the future regulations against coal (as a reliable but highly polluting energy source).
Includes electricity producers, turbine manufacturers, rotor blades, controls, cable systems, etc.
American Public Power Association www.appanet.org/
American Wind Energy Association (AWEA) www.awea.org/
Asociación Española de la Industria Eléctrica (UNESA) www.unesa.es/ (Spain)
Edison Electric Institutie (EEI) www.eei.org/
Electric Power Research Institutie (EPRI) my.epri.com/
Electric Power Supply Asociation (EPSA) www.epsa.org/
Electricity Consumers Resource Council (ELCON) www.elcon.org/
Energy Information Administration (EIA) www.eia.doe.gov/
Federal Energy Regulatory Commission (FERC) www.ferc.gov/
Industrial Energy Consumers of America (IECA) www.ieca-us.com/
National Association of State Utility Consumer Advocates www.nasuca.org/
National Council on Electricity Policy www.ncouncil.org/
National Renewable Energy Laboratory (NREL), United States Solar Atlas mapserve2.nrel.gov/website/L48NEWPVWATTS/viewer.htm
National Rural Electric Cooperative Association (NRECA) www.nreca.org/
North American Electric Reliability Corporation (NERC) www.nerc.com/
Northeast Power Coordinating Council, Inc. www.npcc.org/
ReliabilityFirst Corporation www.rfirst.org/
U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy www.eere.energy.gov/
U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, 20% Wind Energy by 2030 www1.eere.energy.gov/windandhydro/wind_2030.html
U.S. Department of Energy, Small Wind for Homeowners, Ranchers, and Small Businesses www.windpoweringamerica.gov/small_wind.asp
U.S. Department of Energy, Wind Powering America State Activities www.windpoweringamerica.gov/state_activities.asp
U.S. Department of Energy, Wind Resource Maps www.windpoweringamerica.gov/wind_maps.asp
U.S. Senate Committee on Energy and Natural Resources www.energy.senate.gov/public/
