Thursday, May 15, 2008
Turn, Turn, Turn: The Power of Wind
Like solar energy, wind power is very alluring because it's so simple. It comes from wind – a clean, renewable and naturally occurring source of energy. Kinetic energy to be exact.
Kinetic energy can be turned into either mechanical energy or electrical energy. People have been using wind to do mechanical things for centuries like grind grain or pump water. This is what a windmill is used for.
A wind turbine is the proper term for the mechanism used to change wind motion into electricity. The wind blows the blades which are attached to a hub. The hub is mounted on a shaft that spins as the wind blows. A gear transmission box increases the speed of the spinning. This higher energy then travels down a high speed shaft to a generator that makes electricity.
A single smaller turbine can power a home or school, but most often you'll find turbines grouped together into wind farms. This electricity is collected at a substation, increased in voltage, and released along power lines into "the grid."
According to a groovy educational site called EnergyQuest, "The sunlight falling on the United States in one day contains more than twice the energy we consume in an entire year. California has enough wind gusts to produce 11 percent of the world's wind electricity." And another study shows that the potential of wind power on land and near-shore is over five times the world's current energy use in all forms. So I don't really feel like rooting around for the "cons" of wind energy.
But I will.
In order for turbines to work, wind speeds must be between 12-14 miles per hour. Obviously that cannot be a constant. But the solution to intermittency is that, besides storage from peak production times, electricity from different smaller sources can be aggregated into a super-grid, thereby balancing out abundances and deficiencies. The trick is to think about a web of renewable sources, not one everlasting fount.
What about the land mass a wind farm requires? It can actually be twice as productive, as this land can be still be used for agriculture. And what about the carbon footprint of wind energy? The manufacture and construction of wind farms requires the use and transport of large amounts of steel, concrete, and aluminum, but the emission released in this production can be offset in only nine months of operation for off-shore turbines.
Any other cons? While wind turbines don't need water to generate electricity, there have been instances of lubricating oils or hydraulic fluid leakage. In some cases this could contaminate drinking water. Wind turbines also seem to be bat killers.
Hmm. When weighing this against all of the pollution and environmental havoc wreaked by fossil fuels (bye-bye ice caps!), I'm not really deterred.