Publicity related to wind power developments often focuses on wind power’s impact on birds, especially their collisions with turbines. Although this is a valid environmental concern that needs to be addressed, the larger effects of global climate change also pose significant and growing threats to birds and other wildlife species. The IPCC recently concluded that global climate change caused by human activity is likely to seriously affect terrestrial biological systems, as well as many other natural systems (IPCC 2007). A 2004 study in Nature forecast that a mid-range estimate of climate warming could cause 19% to 45% of global species to become extinct. Even with minimal temperature increases and climate changes, the study forecast that extinction of species would be in the 11% to 34% range (Thomas et al. 2004).
The future for birds in a world of global climate change is particularly bleak. A recent article found that 950 to 1,800 terrestrial bird species are imperiled by climate changes and habitat loss. According to the study, species in higher latitudes will experience more effects of climate change, while birds in the tropics will decline from continued deforestation, which exacerbates global climate change and land conversion (Jetz, Wilcove, and Dobson 2007). Wind energy, which holds significant promise for reducing these impacts, can be widely deployed across the United States and around the world to begin reducing greenhouse gas emissions (GHGs) now. Although the effects of wind energy development on wildlife should not be minimized, they must be viewed in the larger context of the broader threats posed by climate change.
A primary benefit of using wind-generated electricity is that it can play an important role in reducing the levels of carbon dioxide (CO2) emitted into the atmosphere. Wind-generated electricity is produced without emitting CO2, the GHG that is the major cause of global climate change.
Today, CO2 emissions in the United States approach 6 billion metric tons annually, 39% of which are produced when electricity is generated from fossil fuels. If the United States obtained 20% of its electricity from wind energy, the country could avoid putting 825 million metric tons of CO2 annually into the atmosphere by 2030, or a cumulative total of 7,600 million metric tons by 2030.
A relatively straightforward metric used to understand the carbon benefits of wind energy is that a single 1.5 MW wind turbine displaces 2,700 metric tons of CO2 per year compared with the current U.S. average utility fuel mix, or the equivalent of planting 4 square kilometers of forest every year.
The fuel displaced by wind-generated electricity depends on the local grid and the type of generation supply. In most places, natural gas is the primary fuel displaced. Wind energy can displace coal on electric grids with large amounts of coal-fired generation. In the future, wind energy is likely to offset more coal by reducing the need to build new coal plants. Regardless of the actual fuel supplanted, more electricity generated from wind turbines means that other non-renewable, fossil- based fuels are not being consumed. In New York, for example, a study prepared for the independent system operator (ISO) found that if wind energy provided 10% of the state’s peak electricity demand, 65% of the energy displaced would be from natural gas, followed by coal at 15%, oil at 10%, and electricity imported from out of state at 10% (Piwko et al. 2005).
In addition, manufacturing wind turbines and building wind plants together generate only minimal amounts of CO2 emissions. One university study that examined the issue (White and Kulsinski 1998) found that when these emissions are analyzed on a life-cycle basis, wind energy’s CO2 emissions are extremely low—about 1% of those from coal, or 2% of those from natural gas, per unit of electricity generated. In other words, using wind instead of coal reduces CO2 emissions by 99%; using wind instead of gas reduces CO2 emissions by 98%.
Switching to a zero-emissions energy-generation technology like wind power contributes to cleaner and healthier air. Moreover, wind power generation is not a direct source of regulated pollutants such as nitrogen oxides, sulfur dioxide, and mercury.
Coal-fired power plants are the largest industrial source of mercury emissions in the United States (NESCAUM 2003). The U.S. Environmental Protection Agency (EPA) (EPA 2007) and the American Medical Association (AMA) note that fetal exposure to methylmercury has been linked to problems with neurological development in children (AMA Council on Scientific Affairs 2004).
Furthermore, according the American Lung Association (ALA), almost half of all Americans live in counties where unhealthy levels of smog place them at risk for decreased lung function, respiratory infection, lung inflammation, and aggravation.