With the price of oil above 50 dollars a barrel and increasing environmental concerns about the burning of fossil fuels; not to mention the spectre of peak oil itself, it becomes clear that we need a new energy strategy.
Many experts believe that it will take several technologies to actually turn the tide on fossil fuel dependence. One of these technologies is wind power. Just as the 19th century belonged to coal, the 20th to fossil fuels, it isn’t far off to say that this one will belong to the sun, wind power and energy from within the earth. Many analysts believe that wind power has the ability to take the lead. You couldn’t ask for a more perfect source of power; clean, abundant, well-suited for any weather, cloudy or not.
Transform Energy in the Wind into Electricity
When the air moves quickly in the form of wind, that motion means kinetic energy. The blades of a wind-electric turbine are especially designed to capture the kinetic energy in wind. Wind turbine blades spin because of lift, the same force that allows airplanes to fly. What happens next is very similar to a hydroelectric setup. When the blades of the turbine capture the wind and start moving, a shaft spins to a generator. The generator then transforms that energy into electricity. All of this takes place in the nacelle, near the hub and rotor, high above the ground.
Industrial Wind Turbines – HAWTs (Horizontal Axis Wind Turbine)
Almost all wind turbines in use today are what are called horizontal axis wind turbine, or HAWTs. These are the turbines with the two or three blades that look like propellor blades. Horizontal axis wind turbines must continuously align themselves with the wind. This is done using a yaw-adjustment mechanism, consisting of gearboxes and small electric motors that move the rotor right or left by degrees. A wind vane is used to position the rotor to capture the most wind available. A large supporting tower is used to ensure the blades clear the ground and to make sure the turbine is at an optimum position for wind speed. Because wind is stronger the higher you go, today’s wind turbines tend to stand pretty tall. Also, doubling the rotor diameter produces a four-fold increase in energy output. Scientists estimate a 12 per cent increase in wind speed with each doubling in height.
Wind turbines today range greatly in their output capacity. From as low as 500 watts they can reach 5 Megawatts, which is enough to power a small town! Wind turbines are often cloistered together in wind farms, the smallest having just a few; the largest having many hundred.
Wind Turbine Capacity in the USA
In 2007 alone, 19696 MW of new wind energy capacity were added, reaching a global capacity of 93849 MW by the end of that year – a 26.6 percent growth rate in a single year! In the United States, the installed capacity of wind energy grew by 45 percent in 2007 and by 50 percent in 2008.
In the title for cleanest, most abundant energy, it’s probably a toss-up between the wind and the sun. In the race for top position, the wind, which has for so long powered sailing ships and windmills, seems to be out in front.
Further reading:
Animation: electricity from wind, How Stuff Works
“Carbon Free Power”, Frontline Special, Heat
