“Wind power offers a scalable and affordable way to reduce the electricity sector's global warming emissions." ~Union of Concerned Scientists
Compared to the environmental impact of traditional energy sources, the environmental impact of wind power is relatively minor. Wind power consumes no fuel and no water and, unlike fossil fuel power sources, has no emissions directly related to electricity production. 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. While a wind energy facility may encompass a large area of land, many land uses such as agriculture and ranching are compatible because turbine foundations and infrastructure have small footprints.
Diversifying our electricity generation portfolio with wind power is an affordable, readily available way to generate electricity in a climate-responsible way that also protects human health and our environment.
Reduced Greenhouse Gas Emissions
Electricity generation is the largest industrial source of air pollution in the United States, and demand for electricity continues to grow. The United States produces 6 billion metric tons of carbon dioxide (CO2) annually. By 2030, this number could reach 6.75 billion metric tons. Forty percent of CO2 emissions are generated by the electric power sector.
Because wind power generates no emissions and displaces CO2 and other greenhouse gases that would otherwise be emitted by fossil fuel-fired electric generation, the clean generation provided by wind capacity displaces millions of tons of CO2 annually.
One megawatt-hour (MWh) of wind energy produced = reduction of 1,200 pounds of CO2 emissions
In May 2008, the U.S. Department of Energy (DOE) released a study of the feasibility of generating 20% of U.S. electricity needs from wind power by 2030. Under this scenario, DOE reported wind energy could avoid 825 million tons of CO2 annually by 2030, cutting expected electric sector emissions by 20% to 25%. This is equivalent to taking 140 million vehicles off the road. Moreover, DOE reported the cumulative effect of achieving 20% wind energy by 2030 would be reducing CO2 emissions by 7,600 million metric tons (and an additional 7,400 million metric tons by 2050).
Reduced Water Use
Because power plants require cooling water, the electricity sector accounts for almost half of all U.S. water withdrawals—more than agricultural irrigation, municipal water supplies, and household use combined (Union of Concerned Scientists 2011). In 2005, U.S. coal, nuclear, and natural gas plants used more than 100 billion gallons of freshwater per day. In addition, as much as 1.7 trillion gallons are lost to evaporation each year (DOE 2008). Power plant cooling systems also draw in and kill billions of fish per year and harm other marine life when cooling water is returned to waterways at dangerously high temperatures (EPA 2011).
In contrast, wind power uses virtually no water. The DOE calculates that generating 20% of the country’s electricity from wind energy by 2030 would reduce the electricity sector’s cumulative water consumption by 8%, saving 4 trillion gallons over 20 years. About 30% of these savings would occur in western states, where water scarcity is an ongoing concern and projected to worsen (Karl, Melillo, and Peterson 2009; DOE 2008). According to a new report from the Union of Concerned Scientists, replacing aging coal, natural gas, and nuclear plants with renewable energy would ease the pressure on dwindling water resources while cutting carbon emissions. By 2050, the power sector could slash its water use by about 97% and its carbon emissions by about 90% from today's levels if more investments are made in renewable energy and energy efficiency.
Fresh evidence of the importance of the water savings from wind energy comes from Western Resource Advocates' new report, A Powerful Thirst: Managing the Electricity Sector’s Water Needs and the Risk of Drought (PDF 1.2 MB). The worldwide wind resource overlaps heavily with drought belts, both present and projected under climate change. The report notes: “Texas’ wind generation — which uses no water — may have mitigated the impacts of drought on the power sector. Texas has over 10,000 MW of wind capacity, a portion of which was generating energy when demands peaked (and thermoelectric cooling supplies were severely depleted) in August 2011.”
Bloomberg New Energy Finance published an article (PDF 148 KB) examining water use by energy generation type.
Wind turbines operate without emitting air pollutants. Generating electricity from wind therefore helps the nation meet its electricity demand while also avoiding the health damages that can come with conventional power generation.
The National Academy of Sciences (NAS) has calculated that electricity generation in the U.S., mainly from coal plants, comes with a hidden cost of more than $60 billion annually in health damages from air pollution. Such pollution includes emissions of sulfur dioxide, nitrogen oxides, and particulates, which combine to form smog. Unhealthy levels of these pollutants place people at risk for decreased lung function, asthma, respiratory infection, lung inflammation, and aggravation of respiratory illness, according to the NAS and the American Lung Association.
No Water Pollution or Waste
Coal burned in power plants is the leading source of human-caused emissions of mercury, which eventually becomes concentrated in fish, such as tuna and swordfish, and can cause brain damage when ingested by young children and birth defects when ingested by women of child-bearing age.
Coal plants also produce solid waste containing heavy metals and other toxic substances that can contaminate drinking water supplies and harm local ecosystems if not disposed of safely. In December 2008, a dike burst at a Tennessee power plant’s impoundment pond, sending an estimated 1.1 billion gallons of coal ash slurry into the Emory River, damaging homes and fouling the water with arsenic, selenium, and mercury (Barton 2010; EPA 2009).
Similarly, spent nuclear fuel contains highly radioactive waste that requires hundreds of thousands of years to decay to the point where it becomes harmless. It also contains large quantities of less radioactive, yet still dangerous, waste (NRC 2010).
Land Use Compatibility
The turbines and related infrastructure of a wind energy project occupy just 2% to 5% of the project area, leaving at least 95% of the land free for other uses (AWEA 2009). Wind turbines around the world coexist safely with schools, highways, hiking trails, and farms.
The direct footprint of a wind turbine is relatively small: a typical 1.5-megawatt turbine measures about 15 feet across its base, and its concrete foundation (set underground) measures about 30 feet per side. In the area immediately surrounding the turbine, vegetation must be cleared to allow for maintenance and overhead transmission lines, if needed in remote locations. Developers also use some land to build access roads.
Wind turbines are usually spaced 5 to 10 rotor diameters apart, depending on the terrain, to maximize performance (Denholm et al. 2009). This can mean as little as 32 acres per megawatt in rolling terrain or up to 50 acres per megawatt in flat areas, with most of that land remaining available for other uses.