Wave energy got a boost with the connection of the Oyster hydro-electric device to the electricity grid in Scotland last Friday.
Aquamarine Power activated the connection of the Oyster in the waters off Orkney, marking one of the few ocean power devices to be producing electricity.
The device is a hydraulic pump operated by a "hinged flap," where a large metal piece moves back and forth from the motion of the waves. The movement moves a hydraulic piston that pumps water underground to a hydro-electric turbine that drives a generator to make electricity.
The peak power output of the Oyster 1 is about two megawatts, depending on the location. The company, which received research funding from the U.K. government, is now working on a second-generation device.
There are a number of technologies being pursued to convert wave or tidal energy into electrical energy, including underwater generators. The advantage of the pump design is that it's relatively simple and many components, such as gear boxes and generators, are not exposed to the water.
Twenty Oysters, which are attached to the seabed at about 10 meters of water, could produce enough electricity to power 9,000 homes in the U.K., according to Aquamarine Power.
In the U.S., the Seadog Pump uses a similar approach of pumping water offshore to a hydro-electric turbine to make electricity.
The Oyster was tested at the European Marine Energy Centre. In the U.S., there is an effort to establish an ocean power research center in southern Massachusetts.