Wind up the wind
Besides being celebrities, Sachin Tendulkar and Aishwarya Rai share interests in wind energy projects. Both have invested crores in wind farms in the country.india Updated: Apr 17, 2006 00:20 IST
Besides being celebrities, Sachin Tendulkar and Aishwarya Rai share interests in wind energy projects. Both have invested crores in wind farms in the country. Even if these are attempts to take advantage of the tax breaks that wind power enjoys, people are increasingly weighing their energy needs against environmental quality. The environmental effects of burning fossil fuels and over-dependence on petroleum are spurring a boom in wind turbine construction across the globe. Unlike fossil or nuclear fuels, wind energy requires no mining, drilling or pumping, and no pipelines. It produces no pollution-like fossil fuels, or radioactive waste like nuclear energy, and doesn’t even need any water for cooling.
Spain has the largest number of wind energy projects in the world, and Germany vigorously promotes wind power for reducing greenhouse gas emissions. In Denmark, wind power is so popular that it even exceeds the country’s economic mainstay: ham!
Wind power is owed to the sun, as it’s the uneven heating of Earth’s surface by the sun’s rays that causes the wind to blow. When solar energy strikes the planet’s surface, it creates pressure differences and the wind moves along the pressure gradients — from higher to lower. Its speed increases when it’s constricted, as when moving through a mountain pass. The faster wind moves, the more energy it carries, which increases with the cube of the wind speed. Thus a wind speed of 8 metres per second (mps) yields 300 watts for every square metre exposed to the wind, while at 16 mps, we get 2,500 watts per square metre, or eight times as much.
Wind turbines are like giant fans run in reverse: airfoils are used to catch the wind and crank a generator, which pumps out electricity. Scientists determine the windiest places by looking for characteristics like exposed terrain, colliding air masses and topographic funneling. Forested areas are a no-no, as are equatorial regions with their light and variable winds.
But this emerging technology faces many challenges. As with geothermal energy and hydropower, the site-specific nature of wind energy could conflict with land uses. The technology challenge is to have larger turbines — as power production rises exponentially with blade length. Reducing energy loss due to machine vibration, developing flexible blade, or even whole machines that swivel with shifting winds (unlike traditional designs that are locked in place)... the answers are blowing in the wind.