For every small step we take towards responsible living—buying eco-friendly light bulbs, and so on—there are gadgets that help us make giant leaps in our quest for sustainability. This week in our Green Tech series, we examine those slim, sexy, spinning energy-harvesters, the fashion models of green tech: wind turbines.
According to the American Wind Energy Association, if we increase our nation's wind energy capacity to 20% by 2030, it would prevent 7,600 million tons of CO2 emissions and reduce water consumption in the electric sector by 4 trillion gallons. As of December 31, 2009, there were turbines generating 34,863 MW of wind power across the US. How do they do it? Well, the technology of a wind turbine is easy to grasp: Wind turns a set of blades (usually two or three) around a rotor that is connected to a main shaft, which spins a generator to create electricity. Check out a snappy little animation of a wind turbine in action courtesy of the US Department of Energy.
The International History of Wind Machines
The first known wind-harnessing device that was used to power a machine is the windwheel. It was developed by Ancient Grecian mathematician Heron of Alexandria—apparently he found time between inventing the vending machine, the syringe, and a bunch of other really useful gadgets to figure out how to make the wind operate an organ. The first vertical axle windmills were built in the 7th century in Sistan, a region between Afghanistan and Iran, and were used to grind corn and draw up water. By the 14th century, the Dutch had become the windmill capital of the world, and by 1900, about 2500 windmills produced an estimated combined peak power of about 30 MW. In 1887 Scotsman James Blyth built and patented (in 1891) the "wind-engine"—the first known electricity-generating windmill. It was used to charge batteries and had a unique feature: a self-braking mechanism that would halt the mill in gale-force winds, to avoid breakage. 40 years later, in 1931, a forerunner of modern horizontal-axis wind generators was in service at Yalta, USSR. It was a 100 kW generator on a 98-foot tower, connected to the local 6.3 kV distribution system. It was reported to have an annual capacity factor of 32 per cent, which is not much different from current wind machines. In the fall of 1941, the first megawatt-class wind turbine, the Smith-Putnam, was synchronized to a utility grid in Grandpa's Knob, Vermont. Sadly, it only ran for 1100 hours until it busted (because of wartime material shortages, it was not repaired).
One of the world's leading wind turbine suppliers, GE, has over 13,500 installations worldwide (that's more than 218 million operating hours and 127,000 GWh of energy produced). The sleek 2.5 MW turbine is equipped with a permanent magnet generator, which, opposed to copper coils, reduces electrical losses in the generator and current flow through the rotating parts of the generator, ensuring high efficiency even at low wind speeds. The world's largest-capacity wind turbine is the Enercon E-126 in Germany, built in 2007. It stands 650 feet tall, is 413 feet in diameter, and has a rated capacity of 7.58 MW. At least four companies are currently working on the development of a 10MW turbine.
Wind Farming 101
If you've ever had the pleasure of vacationing in the southern mountainous regions of the Granite State, you have tread near to the world's first wind farm. Installed on Crotched Mountain in New Hampshire in 1980, it consists of 20 wind turbines rated at 30 kilowatts each. It was a major failure—the developer overestimated the wind resource, and the turbines frequently broke. Cue the sad trombones. The Lone Star State, naturally, is home to the world's largest wind farm, Roscoe Wind Farm, which produces 780 MW of energy. Everything's bigger in Texas! In September, the world's largest offshore wind farm began production off the coast of Kent in the UK, which produces over 1,300 MW of energy—more than the rest of the world combined.
Continued research in sustainable technology is the only way we can responsibly move into the next decade. GE has become a leader in developing and funding projects that help actualize a green future—so GE and its venture capital partners have made a $200 million commitment to invest in the best ideas to develop and deploy digital energy technologies. Head to the GE ecomagination challenge to check out the next great green ideas!
And check back next week when we cover more unique developments in Green Tech!