Wind Energy Currently the world's population uses three main energy sources: fossil, renewable, and fissile. The fossil energy sources are petroleum, coal, natural gas, bitumen, oil shale, and tar sands; the renewable energy sources include biomass, solar, wind, geothermal, and hydropower; and the fissile energy sources are uranium and thorium (Demirbas 212). Demirbas also estimates that at the present rate of production, known petroleum reserves will be depleted in less than 50 years (212). Additionally, energy production from fossil fuels results in high greenhouse gas emissions creating critical environmental problems throughout the world. According to Demirbas energy consumption will be double the 1998 level by 2035 and triple by 2055 if the global growth rate of about 2% a year of primary energy use continues (213). The combination of climate change, escalating oil prices and concerns about long-term energy security has put energy at the top of political and policy agendas for the United States and other countries around the world.

Demirbas explains that while fossil fuels still represent over 80% of total energy supplies in the world today, new technological developments are altering the trend towards new energy sources (213). Biomass, wind, and geothermal energy are all renewable energy sources that are commercially competitive and are making relatively fast progress. However Kaygusuz asserts that wind energy is the fastest growing energy technology in the world (122). Additionally it is one of the most cost-effective ways to generate electricity from renewable sources. This literature review will demonstrate that wind energy is a clean, affordable, renewable, and abundant domestic source of electricity.

According to the U.S. Department of the Interior Bureau of Land Management (BLM) winds are caused by the uneven heating of the atmosphere by the sun, the irregularities of the earth's surface, and rotation of the earth. Wind flow patterns are modified by the earth's terrain, bodies of water, and vegetative cover. This wind flow, or motion energy, can be harvested by modern wind turbines to generate electricity.

The use of wind energy is not a modern phenomenon. Leipoldt explains that the earliest known use of wind power is by the Egyptians 5000 years ago, who used it to sail their boats from shore to shore on the Nile. Around 2000 BC the first windmill was built in Babylon. In Afghanistan large windmills, as high as 30 feet, with 16-foot long blades were being used by the 10th century BC. Chinese and Persian windmills for grain milling date from at least the 13th century. The Dutch have been using windmill technology since 1390 to pump water. According to Leipoldt, without this technology at least a third of the Netherlands would still be covered by water. Compared to the variety of uses that stretch back millennia, converting wind energy to electricity is a recent application (Pasqueletti 24). Pasqueletti also states "Although a few people were trying to accomplish this at the same time Thomas Edison opened his coal-fired Pearl Street generating plant in the latter years of the nineteenth century, it would be another 80 years before such proof-of- concept machines would evolve into the commercial generators that started sprouting in the California landscape in 1981" (24).

Most modern wind power is generated in the form of electricity by converting the rotation of wind blades into electrical current by means of an electrical generator (Kaygusuz 122). According to Bohn & Lant the United States took the lead in wind energy development in the 1980s (88). In the 1990s European developments made the North Sea coast of Denmark, Germany, and The Netherlands the center of world wind power development, with Spain following close behind. In 2006, Denmark led the world with 21.4% of its electrical generation from wind and Germany led the world with 20,652 megawatts (MW) of the worldwide total of installed capacity. Since 2000, however, U.S. wind power has been rejuvenated with installed capacity increasing at an annual rate of 24% from less than 3,000 MW to 11,575 MW in 2006. The United States led the world in 2006 with an annual capacity increase of 2,454 MW, yet wind generated only 0.8% of all U.S. electricity in that year (Bohn & Lant 88). Currently, according to the Massachusetts Executive Office of Energy and Environmental Affairs 29,440 MW of wind energy are currently installed in the United States, and an additional 5,866 MW are under construction. While this is still a small portion of the electricity generated, the Massachusetts Executive Office of Energy and Environmental Affairs estimates that by 2030, wind energy could comprise 20% of the United States supply of electricity with existing technology. McGowan & Connor provides that advances in wind energy system technology during the 1990s have produced major successes in the following three areas:

Cost of delivered energy. This success has occurred as a result of continued technology improvements, increased size and number of sales, and increased financial confidence.
2. Flexibility of wind technology. Because wind energy systems represent a modular technology, it can be added in relatively small steps, making it easier to speed up or slow down introductions to meet immediate economic circumstances. Also, wind technology is relatively easy to transfer, making it attractive to developers in expanding international markets.

3. Availability. The availability, or fraction of time that a wind turbine is available to produce power has increased to the point where values of 98% to 99% are typical for established wind farms. This high level of availability represents values that are higher than many conventional utility scale power generation systems (173).

Kaygusuz explains that most forms of energy production create some form of negative externality; costs that are not paid by the producer or consumer of the good (130). For electrical production, the most significant externality is pollution, which imposes costs on society in the form of increased health expenses, reduced agricultural productivity, and other problems. Significantly, carbon dioxide, a greenhouse gas produced when using fossil fuels for electricity production, may impose costs on society in the form of global warming. Wind power is a renewable resource, which means using it will not deplete the earth's supply of fossil fuels. It is also a clean energy source, and operation does not produce carbon dioxide, sulfur dioxide, mercury, particulates, or any other type of air pollution, as do conventional fossil fuel power sources (Kaygusuz 131). Pasqueletti (30) adds that wind power requires no mining, drilling, or pumping, no pipelines, port facilities, or supply trains (30). It produces no air pollution or radioactive waste, and it neither dirties water nor requires water for cooling. Kaygusuz asserts that because it uses energy already present in the atmosphere, and can displace fossil fuel generated electricity, wind power mitigates global warming (132). According to the Massachusetts Executive Office of Energy and Environmental Affairs, 1 MW of wind energy can offset approximately 2,600 tons of carbon dioxide annually.

In addition to being a clean energy source, wind power is becoming more affordable. As wind turbines are becoming more efficient, the cost of the electricity generation is falling (Demirbas 217). Bohn & Lant (88) explain that prices for wind-generated electricity fell from just over $61/MWh in 1999 to under $35 in 2005 (compared to $40 to $50 for natural gas and $35 to $40 for coal excluding external environmental costs) (88). Prices increased slightly in 2006, however, due to rising demand and increased prices for turbines, the majority of which are produced in Denmark. Kaygusuz adds that most major forms of electric generation are capital intensive, meaning that they require substantial investments at project inception, and low fuel and maintenance costs (123). This is particularly true for wind and hydropower, which have fuel costs close to zero and relatively low maintenance costs; in economic terms, wind power has an extremely low marginal cost and a high proportion of up-front costs. The cost of wind energy per unit of production is generally based on the average cost per unit, which incorporates the cost of construction, borrowed funds, and return to investors, estimated annual production, and other components. According to Kaygusuz, further reductions in the cost of wind energy can be expected through improved technology, better forecasting, and increased scale (130).

Kaygusuz estimates that 1-3% of energy from the sun that hits the Earth is converted into wind energy, about 50 to 100 times more energy than is converted into biomass by all the plants on Earth through photosynthesis (123). Demirbas adds that wind energy is an available in virtually every nation in the world (217). According to Bohn & Lant, potential energy production from wind in the United States is large; the Great Plains region alone has the potential to produce twice the current U.S. electricity demands (88). According to the Massachusetts Executive Office of Energy and Environmental Affairs, a single 1 MW turbine on land can provide enough electricity to power 225 to 300 households. A single 1 MW turbine in an offshore wind farm, where the wind blows harder and more consistently, can power more than 400 households.

According to Thresher, Robinson & Veers 28 states in the contiguous…