An unusual wave-power system that pumps high-pressure water to an onshore hydroelectric plant recently began feeding electricity into the U.K.’s national transmission system. The 315 kW “Oyster device” is the world’s only functioning hydroelectric wave-powered plant, claims its Edinburgh-based developer, Aquamarine Power Ltd.
Oyster’s hydraulic pumping power is generated at the hinge of a seabed-mounted flap that moves with waves. The 10-m-long by 18-m-wide steel flap rises from the machine’s 4.5-m-deep base. Set in 13 m of water, the flap projects above the water surface. For maximum efficiency, “it is really important that the flap penetrates the entire water column and [rises] out of the water,” says the company’s chief technical officer, Ronan Docherty. Maintenance is easier on the Oyster system than on conventional wave-power generators , because the hydoelectric plant is onshore, rather than underwater.