Wind power is one of the oldest sources of energy, and also one of the newest. For thousands of years, humans have used sails to catch the wind and ply the seas. Perhaps as early as the fifth century A.D., windmills were used in Persia to power mills (Gobar). Through most of the twentieth century, windmills seemed a quaint leftover from bygone days, their power dwarfed by that generated from coal, oil, and other fossil fuels. The oil crisis of the 1970s, however, prefigured a change in attitude toward energy that would subside, but be rekindled in the 1990s and beyond, as fears of global warming spurred a search for alternative energy sources.
Like all energy used by humans, wind power has its ultimate origin in the sun. If fossil fuels rely on solar energy stored underground for millennia and solar panels are far more direct, wind power harnesses kinetic energy processes unleashed by the sun. As the American Wind Energy Association (AWEA) explains, "The sun's radiation heats different parts of the earth at different rates--most notably during the day and night, but also when different surfaces (for example, water and land) absorb or reflect at different rates. This in turn causes portions of the atmosphere to warm differently. Hot air rises, reducing the atmospheric pressure at the earth's surface, and cooler air is drawn in to replace it. The result is wind" (Basics). Of course we've all experienced being battered by a fierce wind, but the question is how to harness it for human use. It seems such a diffuse, mysterious, and invisible force.
It is also a powerful force. According to the National Research Council, "two percent of all the energy the earth receives from the sun is converted into kinetic energy in the atmosphere, 100 times more than the energy converted into biomass by plants" (17). Of course enormous amounts of potential wind power will never be harnessed. However, areas where great swaths of wind occur in relatively concentrated force provide great opportunities. This is one reason why modern wind power tends to work via wind farms, large groups of enormous structures situated where the wind is strongest (unlike the more diffuse solar panels, which tend to be situated on individual buildings). Wind also offers the advantages of being endlessly renewable. Unlike fossil fuels, we'll never use it up. And it's extremely clean, emitting no noxious particles or greenhouse gasses.
Wind power does have some disadvantages, the prime one being intermittency. On calm days it disappears. This means that either it must be combined with other sources, such as coal fired plants, to provide consistent power, or ways must be found to store it. Wind turbines also kill birds and bats, and often encounter local opposition from people who feel that they disfigure landscapes.
Nevertheless wind power currently is surging in popularity, part of a desperate search for alternative energy that doesn't add to global warming or other environmental stresses. Unlike solar power, which remains extremely expensive, wind power is cost competitive with fossil fuels such as coal, and is becoming more so. Indeed, "the cost of wind-generated electricity has dropped by more than 80% since the early 1980s. A modern, state-of-the-art utility-scale wind turbine can generate electricity for 4 cents per kilowatt-hour, which is nearly competitive with fossil fuels" (AWEA Economic). As other energy sources become more expensive, and wind technology continues to improve, wind will become even more cost competitive.
Given these factors, it is not surprising that the use of wind power is increasing rapidly. Just a few years ago wind was mostly relegated to a few European countries such as Holland and Germany. Indeed, "the use of wind energy for electricity generation, which began on a utility scale in about 1980, grew relatively slowly at first with only about 3 gigawatts (GW, one billion watts) installed by 1993. However, by 2003, the world's wind-energy capacity was 39.4 GW, and by 2005 it was more than 59 GW" (NRC 41). Wind is now a popular source of energy in China, India, and the United States. In the coming years this gust toward wind power should reach hurricane force, as wind turbines become ubiquitous, powering our homes and our businesses with limitless free energy while doing little harm to the environment.
The environmentalist belief in wind as a superior energy option is becoming widespread. In 2005 Greenpeace argued that "the wind industry of today is one the world's fastest growing energy sectors and offers the best opportunity to begin the transition to a global economy based on sustainable energy" (2). In the short period since that was written, wind energy use has grown even faster: "Wind energy had a breakout year in 2007, according to an annual survey by the American Wind Energy Association. Producers invested $9 billion to install a record 5,244 megawatts of electrical generating capacity in the United States last year, boosting the country's total wind capacity by 45 percent to 16,818 MW. Wind accounted for 30 percent of all new generating capacity in 2007. . . . Yet the association expects wind to generate 48 billion kilowatthours in 2008, just over 1 percent of all U.S. electricity and enough to supply 4.5 million homes" (Brown). And the potential for growth remains huge: "According to the U.S. Department of Energy, the world's winds could theoretically supply . . . more than 15 times current world energy demand" (AWEA FAQs 9).
Go To How Wind Turbines Work
List of Visuals
- Don Quixote in his legendary 17th century battle with Spanish windmills
- Wind turbines at the Horns Reef wind farm
in Denmark, some 20 kms (12 miles) off the port of Esbjerg
Jorgen True, Copyright 2007, Getty Images
- World Wind Energy Generating Capacity, 1980-2007
Janet Sawin. Wind Power Continues Rapid Rise. Worldwatch Institute, April 2008