Wind farms could meet energy needs
Wind power could generate more than enough sustainable electricity to meet global energy needs, according to new research.
Scientists at Stanford University have produced a world map that plots wind power potential for the first time.
They say that harnessing even 20 percent of that energy would produce eight times more electricity than the world consumed in 2000.
"The main implication of this study is that wind, for low-cost wind energy, is more widely available than was previously recognized," said Cristina Archer, formerly of Stanford's Department of Civil and Environmental Engineering.
Archer and colleague Mark Jacobsen collected wind-speed measurements from 7,500 surface stations and 500 balloon-launch stations to determine wind speeds at 80 meters (300 feet) -- the height of modern turbines.
They found average wind speeds capable of generating power -- upwards of 6.9 meters per second, or 15 miles an hour -- in 13 percent of the stations and in all regions of the globe.
North America had the greatest potential for wind energy with consistent winds found in the Great Lakes region and along both the north-eastern and north-western coasts.
Some of the strongest winds were found in northern Europe in the North Sea, off the southern tip of South America and around the Australian island of Tasmania .
Wind is already the fastest growing source of energy in the world, with average annual growth of 34 percent over the past five years. But it currently produces just 0.54 percent of electricity used.
Installed annual capacity at the end of 2003 stood at 39,000 megawatts, or 39 million watts.
produced almost 40 percent of that total, with wind power contributing 20 percent of its overall electricity supplies.
But Archer and Jacobsen, whose research is published in the Journal of Geophysical Research-Atmospheres, estimate that locations with sustainable winds could produce approximately 72 terawatts -- or 72 trillion watts -- a year.
It would take more than 500 nuclear power stations to generate a terawatt and in 2000 the world consumed just 1.8 terrawatts in total.
Critics of wind power say that densely packed wind farms would be needed to capture an acceptable level of energy, spoiling their local environment and posing a threat to bird life. They also say that winds are unreliable and that back-up sources of energy would still be necessary.
But the pair said they hoped the study would help planners to identify good locations for wind farms, particularly in developing countries. Currently many farms are located inland, where winds are intermittent.
Tom Gray of the American Wind Energy Association told Nature that the map was of interest to the wind power industry.
"From the early days, there has been an issue with where the resource is," he said.