The breezes are blowing stronger for the wind-power industry these days – so much so that the National Renewable Energy Laboratory in Golden had to redo its wind maps in Colorado and in states across the country.
The reason isn’t meteorological, it’s technological as wind-turbine towers get taller and blades get longer.
“The original maps were for 50-meter towers, but the industry standard is now 80 meters,” said Dennis Elliot, a principal scientist at NREL.
And as the towers have grown from 164 feet to 262 feet, they have edged into the reaches where the winds are stronger and more sustained.
Under the old map, the strongest winds in Colorado – clocked at 7.4 meters to 8.4 meters a second – were in the northeast and southeast corners of the state.
At 80 meters above ground level, the wind speeds across a large portion of the Eastern Plains and Front Range vary between 8.5 meters and 10 meters a second.
“What that has done is make Colorado’s good wind resource even better,” Elliot said.
“In places like Indiana, the 80-meter towers and technology has meant the difference between not having an economical wind source and having one,” Elliot said.
The difference in a few meters per second of wind power adds up.
The new technology combined with the steadier winds are driving down the costs of wind generation, according to economic analyses.
A California Energy Commission analysis estimated that a 0.5 meter increase in wind speed – raising the resource from “good” to “excellent” – would cut 1.2 cents off the cost of electricity from a new wind farm to 10.8 cents a kilowatt-hour.
That study was based on 50-meter winds and the costs of developing a wind farm in California.
In a U.S. Energy Information Administration study, the difference between a top wind resource and a poor one is more than 3 cents a kilowatt-hour, with the best resource producing wind at 8.1 cents a kilowatt-hour.
It isn’t just that the taller towers and bigger blades capture more wind at 80 meters, it is that they can also turn more of the time.
Electricity from coal and gas is cheaper because the sources can run 70 percent to 90 percent of the time – this is called the capacity factor.
The capacity factor for wind farms has been around 30 percent, according to the American Wind Energy Industry Association, a trade group.
In Colorado, for example, the wind tends to blow at night.
“We are now getting some capacity factors to 50 percent,” said Matthew Kaplan, associate director of IHS Emerging Energy, a Boston- based consulting firm.
The result is that wind power has become more marketable, said Ron Lehr, Western representative for the wind energy association.
“You look at the new maps and there are opportunities for wind across the country,” Lehr said.
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