Wind has been harnessed to produce energy for hundreds of years. The use of windmills to catch air currents and translate that force into mechanical energy dates back to medieval Europe, and perhaps beyond. Today wind power is the second fastest growing energy source in the world1 and “one of the most mature technologies for generating energy from renewable sources.”2
In 2011, 50 countries installed wind power capacity.3 This expansion is largely the result of technological innovations that have reduced the costs of constructing wind turbines by 80 percent since the 1980s4 and created of economies of scalesavings achieved because an initial investment is spread out over increasing numbers of produced units.5 In 2012, the world had about four times the amount of wind power capacity than it did in 2005. In 2011, China increased its percent share of global capacity (43 percent), as did the U.S. (17 percent), India (7 percent), and Germany (5 percent).6 The top five global producers of wind energy in 2011 were China, the United States, Germany, Spain, and India.7 These days, wind power is predominantly used to produce electricity using turbines. Most of these turbines are oriented on a horizontal axis and are shaped like the propeller on an airplane.
But an increasing number are built around a vertical axis and look like an “egg-beater.”8 Employing vertical-axis turbines raises the capacity of wind harvesting from 25-40 percent to 43-45 percent. While this might not initially seem like a significant increase, it makes wind power much more economical and allows turbines to harvest more high-speed winds. This is important because “each doubling of wind speed results in an eightfold increase in available energy.”9
Wind power generation facilities are generally land-based, though the number of offshore facilities has been rising in recent years, especially in Europe. Locating wind turbines offshore is more expensive, but it also allows for the construction of larger facilities and increases their capacity to generate power. The fact that many of the best land locations are already occupied has further spurred the development of offshore sites.
In May 2009 the first off-shore wind farm was approved by the state of Massachusetts. “Cape Wind” has been a controversial topic in communities around Cape Cod and the Nantucket Sound for almost ten years. The wind farm seems to have high public approval, so there is optimism that “Cape Wind” will expand the possibility for more offshore wind farms.10 “Cape Wind” received federal approval in 2010, in 2011, received the necessary permits from the Environmental Protection Agency (EPA), Army Corps of Engineers and the Bureau of Ocean Energy Management, Regulation and Enforcement.11 Despite Cape Wind’s early start, Virginia might be the first state to have an operating offshore wind farm. Other U.S. offshore wind projects are in development in Maryland, Delaware, Massachusetts, New Jersey, North Carolina, Ohio, Rhode Island and Texas.12 13
Cost and Efficiency Management
Despite its benefits, expanding wind power also has costs. Some argue the industrial materials and processes needed to build wind farms require so much conventional energy that the net energy gainsA situation in which more energy is produced than expended yielded by wind power are too small to be significant. Others argue that production costs for a turbine are recovered within six months of the start of operations.
There is also the problem of intermittency and storage. Wind energy is only as reliable as the wind itself. Because of this and because it often experiences a more variable demand than traditional coal- or gas-based power plants due to its more localized distribution, wind farms require sophisticated methods of managing and storing energy. This can often decrease the efficiency and raise the cost of wind power. It is likely that better ways of managing these energy flows will be discovered as the technology continues to mature.14
Aesthetics and Ecological Impact
More serious concerns about wind power center on its aesthetics and environmental/ecological impact. Some people find the sight of wind turbines attractive but many do not, considering them a form of “visual pollution”. The fact that turbines are often located in more remote and sometimes scenic areas can make their appearance more objectionable to local residents.
For example, inhabitants of England’s northwest Lake District region, a large area made up of national parks of striking natural beauty, have been particularly vocal in objecting to wind farms in their backyards, even though the District’s many hills would provide ideal sites for an extensive development. The plan was eventually thrown out.15
Perhaps even more pressing than aesthetics, however, are environmental and ecological concerns. Because significant distances must be placed between each turbine in order for wind harvesting to be efficient, turbines are considered to have a large “footprint” on the ground. Translated into practical terms, this means that, wind farms require far more territory than conventional power plants to produce the same amount of energy.16 Especially in more remote areas, this footprint can interfere with the local ecology, disrupting the habitats of both plants and animals.
In addition, the action of the blades on a turbine poses serious safety risks to birds, especially during the night. Defenders of the environment feel it is their duty to protect these creatures from harm, because “the seagulls don’t vote.”17
A Landscape for Development
Wind power is an excellent example of how renewable energy technologies that are generally environmentally-friendly can also create new environmental problems of their own. The benefits of clean energy production must be carefully weighed against the environmental impact and effects on local quality of life.
According to Stephen Tindale, Executive Director of Greenpeace UK, “It’s a major psychological and cultural challenge for the environmental and conservation movement…What we need to combat climate changethe worldwide rise in temperatures that has been blamed for severe weather in many parts of the world. is a complete transformation of our energy system, and that requires a lot of new stuff to be built and installed, some of it in places that are relatively untouched.” In other words: “The biggest hurdle is creating a landscape for development.”18 This is both the challenge and the opportunity presented by many forms of renewable energy.
Wind Generation Picture Source: http://www.eia.doe.gov/kids/energyfacts/sources/renewable/wind.html
Picture Horizontal Wind Turbine, Source: http://www.eia.doe.gov/kids/energyfacts/sources/renewable/wind.html