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New global wind map may lead to cheaper power supply

Stanford researchers have produced a new map that pinpoints where the world's winds are fast enough to produce power. The map may help planners place turbines in locations that maximize power harnessed from winds and provide widely available low-cost energy. After analyzing more than 8,000 wind-speed measurements to identify the world's wind-power potential for the first time, Cristina Archer, a former postdoctoral fellow, and Mark Z. Jacobson, an associate professor of civil and environmental engineering, suggest that wind captured at specific locations, if even partially harnessed, can generate more than enough power to satisfy the world's energy demands. Their report appears in the May Journal of Geophysical Research-Atmospheres, a publication of the American Geophysical Union.

"The main implication of this study is that wind, for low-cost wind energy, is more widely available than was previously recognized," said Archer, now a researcher at the Bay Area Air Quality Management District.

The researchers collected wind-speed measurements from approximately 7,500 surface stations and 500 balloon-launch stations to determine global wind speeds at 80 meters (300 feet) above the ground surface, which is the hub height of modern wind turbines. Using a new interpolation technique to estimate the wind speed at hub height, the authors reported that nearly 13 percent of the stations had average annual wind speeds strong enough for power generation.

Wind speeds of 6.9 meters per second (15 miles per hour) at hub height, referred to as wind power Class 3, were found in every region of the world. Some of the strongest winds were observed in Northern Europe, along the North Sea, while the southern tip of South America and the Australian island of Tasmania also featured sustained strong winds. North America had the greatest wind-power potential, however, with the most consistent winds found in the Great Lakes region and from ocean breezes along coasts. Overall, the researchers calculated hub-height winds traveled over the ocean at approximately 8.6 meters per second and at nearly 4.5 meters per second over land (20 and 10 miles per hour, respectively).

The authors found that the locations with sustainable Class 3 winds could produce approximately 72 terawatts. A terawatt is 1 trillion watts, the power generated by more than 500 nuclear reactors or thousands of coal-burning plants. Capturing even a fraction of those 72 terawatts could provide the 1.6 to 1.8 terawatts that made up the world's electricity usage in 2000. Converting as little as 20 percent of potential wind energy to electricity could satisfy the entirety of the world's energy demands.

The study, supported by NASA and Stanford's Global Climate and Energy Project, may assist in locating wind farms in regions known for strong and consistent breezes. In addition, the researchers suggest that the inland locations of many existing wind farms may explain their inefficiency.

"It is our hope that this study will foster more research in areas that were not covered by our data, or economic analyses of the barriers to the implementation of a wind-based global energy scenario," Archer said.