The Greek god of wind, Aeolos, would be pleased. Over the past 20 years, the world has been getting more of its energy from wind, a clean and inexhaustible resource. But is there enough to be reliable? Scientists have measured breezes in a new way and they find they may be even more powerful than thought.
Wind energy is one of the world's fastest growing technologies. The European Wind Energy Association says air currents have supplied the world with 30 percent more power each year for the last six years.
North America, China, Japan, India, and parts of South America and Europe are turning to it. Denmark gets nearly a fifth of its energy from wind, the highest proportion of any nation.
Behind the advance is a sharp price drop. A Washington organization that promotes renewable energy, the Earth Policy Institute, says U.S. wind power, for example, costs less than four cents per kilowatt-hour, one tenth the price 20 years ago. This makes it competitive with coal and natural gas. By 2020, it is expected to fall to half of today's price.
Now, a recent study in the Journal of Geophysical Research indicates that wind might be more abundant and reliable than we thought.
"The most interesting result was that we found some new areas of strong wind," Stanford University engineering professor Mark Jacobson said, "We're looking at that because wind turbines require fast winds, and the faster the wind, the more power generated by the turbines."
Mr. Jacobson and a colleague measured air currents at hundreds of U.S. locations at a height of 80 meters, the typical height of a large turbine. By using a more accurate method for estimating speed, they found that gusts blew harder than previously calculated, an average of nearly two meters per second faster.
"Twenty-four percent of the surface area of the U.S. has winds fast enough that if you put up wind turbines, the direct cost of energy will be competitive with coal and natural gas," Mr. Jacobson said. "That means there's plenty of wind resources in the U.S. to in fact displace coal and natural gas. That is critical since global warming is an important issue."
Is wind as gusty elsewhere? To find out, Mr. Jacobson will map it on the other inhabited continents. This will help wind power companies decide where turbines would be economical. Professor Jacobson's U.S. study also found that by linking as few as eight wind farms within a few hundred kilometers of each other, he could guarantee a constant flow of wind.
"Even though you might have slow winds in one location, there will be slightly different winds somewhere else. And the more farms you link together, the more consistent the output of energy over all the farms," Mr. Jacobson said.
A trade association of U.S. electric power suppliers, the Edison Electric Institute, says the study eliminates the concern that wind power is intermittent and unreliable. But spokesman Jim Owen disputes Mr. Jacobson's idea that it would be competitive with coal and natural gas everywhere.
Mr. Owen said "Wind farms tend to be located somewhat remote from where people are actually using the electricity. Well the problem with that is you need to have transmission facilities to move the wind [power] from where it's generated to where it's being used and that unfortunately costs a lot of money. So to infer that coal and natural gas as a form of making electricity will be going away anytime soon is probably not a realistic proposition."
Mark Jacobson agrees that it will be difficult to displace coal and natural gas, but only because they are underpriced. He says they would be more expensive if they reflected hidden costs linked to pollution and health problems and if their producers did not get more favorable tax benefits than the wind industry.
The Earth Policy Institute acknowledges that wind power is not yet practical everywhere. The group's president, Lester Brown, says solar energy may be better in regions without electric power lines and where people use small amounts of power. But Mr. Brown thinks wind will eventually become the world's leading energy source.
"Wind is a growth industry," He said. "We now have the technology to convert it into cheap electricity. So the only question in the future is not if the wind is going to find its place in the sun, so to speak, but how fast it's going to do it."
The American Wind Energy Association points out that the rate will depend largely on policy makers' decisions over the next several years.