This is an excerpt from EERE Network News, a weekly electronic newsletter.

November 17, 2004

German Company Erects Prototype 5-Megawatt Wind Turbine

Twilight photo of two cranes lifting the three-blade rotor just off the ground as the turbine waits on its nearby tower

Two cranes lift the rotor to its mount on the REpower 5M turbine.
Credit: LM Glasfiber A/S

The largest wind turbine yet is now operating in northern Germany. Although designed for offshore wind plants, REpower Systems AS installed the 5-megawatt prototype on land for ease of testing. The hub of the massive turbine stands 120 meters off the ground, and the 120-ton rotor, featuring wind blades from LM Glasfiber A/S, has a diameter of 126 meters. REpower began building the "5M" wind turbine in April, completed it in October, and expects to connect it to the electrical grid before year's end. See the LM Glasfiber press release and the REpower 5M Web site.

Given the massive size of the newest generation of wind turbines, you might wonder if they can affect the circulation of wind on a large scale. Researchers from the University of Calgary and Carnegie Mellon University were wondering the same thing, and decided to plug the drag created by wind turbines into the global circulation programs that are used to model the Earth's climate. Their study found that wind power at very large scales—two terawatts, or about 125 percent of today's global electrical capacity—can produce "non-negligible climatic change," causing slight heating and cooling in specific parts of the globe. The authors concluded: "Although large-scale effects are observed, wind power has a negligible effect on global mean surface temperature, and it would deliver enormous global benefits by reducing emissions of (carbon dioxide) and air pollutants. Our results may enable a comparison between the climate impacts due to (large-scale) wind power and the reduction in climatic impacts achieved by the substitution of wind for fossil fuels." See the study (PDF 899 KB), published in the November 16th edition of Proceedings of the National Academy of Sciences. Download Acrobat Reader.