Giant Wind Turbines

Floating wind farms placed far offshore could lead to affordable electricity -- without cluttering the view.

Huge turbines mounted on floating platforms could make wind power competitive with fossil-fuel-generated electricity. These advanced wind turbines, which are in development, could be situated far from the shore, too, avoiding battles with onshore residents who object to the presence of large wind farms.

GE has announced a $27 million partnership with the U.S. Department of Energy to develop 5-7 megawatt turbines by 2009, each of which could power well over 1,000 homes. Supplanting the company's current 3.6 megawatt turbines, these giant energy factories should make wind power more economical, since the major cost of building and installing offshore wind farms does not depend primarily on a turbine's size, but on the number of them that need to be erected. By 2015, GE could have even bigger, 10-megawatt turbines, according to Jim Lyons, leader of advanced technology for GE's wind energy business.

[For images and illustrations of wind turbines, click here.]  

Making the turbines larger, however, comes with technical challenges. The new turbines will be mounted to towers rising 90 to 95 meters and will have rotors measuring 140 meters in diameter. Imagine a structure larger than a football field rotating at a leisurely ten to twelve revolutions per minute. To decrease the weight of the massive rotor blades and tower, GE plans to use composite fibers, as well as alternatives to the weighty gearboxes now used to transfer energy from the rotor to the electrical generator.

The new turbines will also need to be more reliable than their onshore counterparts, because maintenance will be far more difficult and expensive. GE is developing new ways to deal with the extreme battering the turbines will receive from the wind.

Today's turbines compensate for changes in wind speed by actively turning their blades to catch less wind. The new turbines will adapt to gusts by using sensor-based technology that will quickly angle the blades out of the wind to reduce the wear and tear on the turbine. These sensors could include basic accelerometers, embedded fiber-optic sensors that detect shape changes in the blades in response to gusts, and forward-looking, laser-based "radar" that allows the turbine to anticipate wind-speed changes.

None of these technological advances will make a difference, however, if erecting monstrous turbines is blocked by shoreline residents who see them as visual pollution. A potential solution is floating platforms that allow the turbines to be located farther out in the sea -- and out of sight. Current projects locate wind turbines in waters less than 20 meters deep. Going farther out on the continental shelf, which extends several hundred kilometers from the U.S. East Coast, would mean locating them at depths up to 50 meters, which is probably too deep to build towers or trusses that support turbines standing on the sea floor, at least at an affordable cost.