Future Now
The IFTF Blog
Taking windfarms far off shore
"Deep-sea oil rigs floating miles away from land suck natural resources out from the ocean floor, why not build giant floating turbines that collect the wind out on the open seas? MIT researchers in collaboration with the National Renewable Energy Laboratory are designing huge floating wind turbines with 90 meter tall towers outfitted with rotors that are 140 meters in diameter. Engineering professor Paul D. Sclavounos is planning to build a half-scale prototype and install it near Cape Cod as a proof of concept. According to his calculations, 400 full-size units floating 100 miles out to sea completely out of public sight could power several hundred thousand homes. From the MIT Laboratory for Energy and the Environment:
Sclavounos, a professor of mechanical engineering and naval architecture, has spent decades designing and analyzing large floating structures for deep-sea oil and gas exploration. Observing the wind-farm controversies, he thought, "Wait a minute. Why can't we simply take those windmills and put them on floaters and move them farther offshore, where there's plenty of space and lots of wind..."
Their design calls for a tension leg platform (TLP), a system in which long steel cables, or "tethers," connect the corners of the platform to a concrete-block or other mooring system on the ocean floor. The platform and turbine are thus supported not by an expensive tower but by buoyancy. "And you don't pay anything to be buoyant," said Sclavounos.
According to their analyses, the floater-mounted turbines could work in water depths ranging from 30 to 200 meters. In the Northeast, for example, they could be 50 to 150 kilometers from shore. And the turbine atop each platform could be big--an economic advantage in the wind-farm business. The MIT-NREL design assumes a 5.0 megawatt (MW) experimental turbine now being developed by industry. (Onshore units are 1.5 MW, conventional offshore units, 3.6 MW.)