MIT researchers are working with Portuguese colleagues to design a pilot-scale device that will capture significantly more of the energy in ocean waves than existing systems, and use it to power an electricity-generating turbine.

Schematic of an oscillating water column. Waves enter through a subsurface opening into the chamber with air trapped above. The wave action causes the captured water column to move up and down, pushing the trapped air into an electricity-generating turbine. The turbine turns continuously, despite the changing direction of the air stream as the waves come in and out. (Credit: Graphic courtesy / MIT Energy Initiative)

Wave energy is a large, widespread renewable resource that is environmentally benign and readily scalable. In some locations — the northwestern coasts of the United States, the western coast of Scotland, and the southern tips of South America, Africa and Australia, for example — a wave-absorbing device could theoretically generate 100 to 200 megawatts of electricity per kilometer of coastline. But designing a wave-capture system that can deal with the harsh, corrosive seawater environment, handle hourly, daily and seasonal variations in wave intensity, and continue to operate safely in stormy weather is difficult.

Chiang Mei, the Ford Professor of Engineering in the Department of Civil and Environmental Engineering, has been a believer in wave energy since the late 1970s. After the recent oil-price spike, there has been renewed interest in harnessing the energy in ocean waves.

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