As the road crests the top of a rise, they come into view: a line of wind turbines stretching off into the distance, silently rotating their slender pale arms as they work to convert wind energy into electricity. This is becoming a familiar sight in many parts of the world, as many countries try to reduce their consumption of fossil fuels. Wind power is widely available, renewable, and produces no greenhouse gas emissions. So where have we come from and where do we stand in terms of wind energy?
Humans have a long history of harnessing the power of the wind to our benefit. More than 5000 years ago, Egyptians made the first sailboats, using the wind to propel their crafts along the Nile. True windmills first appeared around 2000 B.C., and by the tenth century A.D. were being used to pump water in China and to grind grain in what is now Iran and Afghanistan. The Western world did not begin to use wind power until the 12th century, first for milling grain, and then for draining lakes and marshes, most famously in Holland.
The first wind turbines (windmills used to produce electricity) were built in Scotland in 1887, and independently in Cleveland, Ohio a year later. By the end of the 19th century in the United States, six million wind turbines were spinning, most working to generate power to farms. Expansion and development of wind power continued until the early 1950s, when with the Rural Electrification Administration nearly every American house was put on the power grid, effectively shutting down the market for wind power. This changed in the 1970s, when the OPEC Oil Embargo led to rising oil prices and a renewed interest in wind energy. In the United States, tax incentives and government-led research have sustained this interest, and wind-powered generators today provide more electricity to individual residences and national electric transmission systems than ever before.
So how does a wind turbine actually generate electricity from wind? There are three parts to the most basic wind turbine: rotor blades, a shaft, and a generator. When wind moves the rotor blades, it transfers its kinetic energy (energy of movement) to them. The center of the rotor is connected to the shaft, which spins as the rotor does. The other end of the shaft enters an electrical generator, which uses the process of electromagnetic induction to produce electricity. Most simply: inside the generator the spinning shaft causes an assembly of magnets to spin around a coil of wire, generating electricity. Check out the Department of Energy’s interactive graphic on wind turbines here: http://energy.gov/eere/wind/how-does-wind-turbine-work.
Compared with traditional energy sources, the production of wind power has relatively minor environmental effects. Wind turbines produce clean, renewable energy and use little land. The main impact is ecological. Most affected are birds and bats, directly killed in the thousands by flying into turbines, or indirectly by habitat degradation for new wind farm development. In an effort to minimize disturbance, recent construction has taken into account bird habitat and migration patterns, and new, less-dangerous turbines are being designed. In the end, the jury is still out on the threat actually posed by these structures. Wind turbines kill fewer birds annually compared with other man-made structures, and the biggest threat to bird populations remains feral and domestic cats, which kill billions of birds each year in the United States alone.
Today, wind energy is the fastest-growing source of electricity in the world. By the end of 2013, the US had produced over 61 gigawatts of wind power capacity, which is enough electricity to power almost 16 million homes. Globally, the amount of electricity produced in the same year was over 318 gigawatts. Wind energy is also cost-effective, since the fuel itself costs nothing (installation and operating expenses for the turbines still apply). Each year, as we learn more about how to most efficiently generate and store wind power, we get a little closer to solving the problem of renewable energy that has haunted us for years. Is wind power alone the solution? Probably not. But every step helps.