No question there is a case to be made for drawing electrical power from the wind. Power utilities say they're eager to generate electricity using a clean fuel with little environmental impact, and they have customers lined up and waiting. Turbine and blade manufacturers, most based in Europe, are also eager for the opportunity to serve 300 million U.S. consumers.
But most important, the U.S. government is greasing the skids for wind power, making all this possible with healthy subsidies and mandates that power companies adjust generation portfolios so about 15% comes from "alternative" energy sources. Wind-power proponents say it would be feasible for the U.S. to get 20% of its power from wind by 2020. The current figure is only 0.8%.
But this hardly means we should throw caution to the wind.
ONLY WHEN THE WIND BLOWS
Needless to say, wind turbines only generate electricity when the wind is blowing. This translates into an average output equaling roughly 30% of total rated capacity. Thus for customers such as hospitals and Internet companies who need uninterrupted service, every megawatt of power created by a wind turbine must be backed up by an equal amount of power from more reliable sources, such as a nuclear or coal-burning plant. But it is inefficient to run power plants at less than 50% of capacity. So wind power may make most sense as a means of avoiding brownouts rather than as a competitor for conventional power facilities.
Researchers have also proposed several ways to overcome wind's intermittence. Most involve storing windgenerated energy either by cracking water into hydrogen or pumping water into reservoirs, reclaiming potential energy as water passes through a hydroelectric dam. Other schemes involve charging batteries. One of the more ambitious ideas is to carefully monitor utility-power demand and real-time wind conditions, then balance the two by bringing turbines on and off the power grid. And even this might not be possible without new, more efficient transmission lines.
Most windmill manufacturers are European and the euro is currently at record highs against the dollar. So it's pricey to import wind-turbine capital equipment like 50-m pylons, 30-m blades, and large generators. Some wind-industry experts predict prices will continue to climb by about 1.5% annually. Economists see this as potentially good news for the U.S., believing it will spur development of homegrown wind-turbine companies. They estimate that a continuing interest in wind power could create 3.7 million jobs.
There's also debate among wind-industry leaders about the best way to site wind farms. Where wind condition are best, demand tends to be weak. And close to urban centers, wind conditions aren't always that great. Of course, breakthroughs in transmission or energy storage could render such questions moot.
KEEPING IT GREEN
The biggest factor in wind power's favor is its portrayal as a 100% clean source of renewable energy. But wind has its detractors. Some upscale residents of Martha's Vineyard and Cape Cod, Mass., for example, oppose a wind farm there. The Cape Wind project would consist of 130 spinning wind turbines covering 25 square miles. Though the site would be more than 6 miles from shore, residents fear it would spoil the scenery and kill fish and birds. The environmental activists group Greenpeace, however, insists that offshore windmills pose no threat to marine or avian life.
Those living near wind turbines sometimes complain about the noise the spinning blades create. They say it's unbearably loud, almost like a jet airplane. But wind-turbine makers say the noise issue is all but resolved. Newer blade technologies limit noise, and zoning ordinances can be written to regulate it.
Finally, there is the issue of energy use. Though wind turbines don't consume fuel, it takes at least 150,000 lb of steel, concrete, and fiberglass to build a single 3-MW turbine. Thus, turbines have a carbon footprint that is laid down before they ever generate a single kilowatt. And detractors point out that steel and concrete are both energy intensive, carbon-emitting industries. There are also networks of roads needed to service wind farms. And wind turbines take land, somewhere between 60 and 300 acres/MW. (For comparison, nuclear and coal plants generate about 1,000 MW/acre).
There are several European countries with significant wind-power experience. They offer lessons about what works and what doesn't. For example, Denmark is the country getting the largest percentage of its electricity from wind turbines. But Danes also pay more for electricity than anyone else. The average Dane pays 34¢/kw-hr, according to Eurostat, the statistical office of the EU. In the U.S., that rate varies from 5¢ (Ohio) to 15¢ (Calif.) per kw-hr. And if today's warnings over global warming eventually turn out to be false alarms, the limits on economic growth imposed by higher electrical costs may seem like a bad bargain.
American wind Energy Assoc., www.awea.org