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Wind Energy

July 15, 2003

A public radio commentary

Energy from the wind is renewable and pollutes very little, yet the wind supplies only about one percent of the United States electricity. Why such a small amount?

There are several reasons that wind energy hasn't been universally adopted in the United States.

First, wind energy only recently became cheap. The most important piece of machinery in turning wind into electricity is a turbine. The large blades of the windmill spin the turbine, and its motion turns wind energy into electricity. A turbine, of course, is the same thing that drives a jet. So naturally the first manufacturers of turbines for capturing wind power based their designs on jet engines. But this yielded wind turbines that were inefficient, making the cost of a kilowatt of wind energy about 40 cents in the early 1980s - many times more than fossil fuels.

Today's state of the art windmill is fifteen stories tall, with blades 200 feet or more across. They move very slowly, typically about fifteen revolutions per minute, a tenth that of older systems. New turbines are so efficient that wind energy costs about the same as coal, natural gas or nuclear.

With these advances, what's the problem now?

It's this: You have to build the wind mills where there is wind. Typical places for wind farms, as they call banks of windmills, are plains, shorelines, the tops of hills, and the narrow gaps between mountains. Places rarely near transmission lines.

The United States transmission system was designed to supply electricity to a local area, so power plants are typically built near cities. Since we build our cities where the wind doesn't blow, there are no power lines near wind farms. This calls for building costly transmission lines over unforgiving terrain.

In addition, wind power differs from fossil and nuclear fuels in a critical way: It can supply steady electricity, but not a burst of electricity. Utilities use coal- and nuclear-powered plants, in addition to peak plants that kick in when demand is greatest. Engineers are designing special batteries to supply energy when the wind dies down, but the problem hasn't been solved yet.

To find the solutions we might look to other countries. For example, Denmark gets one-third of their electricity from wind. Yet, oddly this highlights the scale of the problem in bringing wind power to the United States. Denmark is slightly smaller than Vermont and New Hampshire combined and has a population about that of Chicago. To generate their electrical energy from wind takes over 6,000 wind turbines, located off-shore.

So, wind power isn't the pancea that will save us. The most optimistic estimate I can find is from the American Wind Energy Association. They think that about six percent of America's power will be from wind in the next twenty years. Mostly likely wind power will be part of a patchwork of many energy systems that, if all goes well, will supply the energy needs of the United States.

Copyright 2003 William S. Hammack Enterprises