British engineer Alvin Smith has created a simple system to generate electricity on land from waves at sea.
Watch the waves, and you are seeing ocean energy at work. Extracting it is no easy job, though. Now, renewable energy supplier Ecotricity is backing the simplest wave energy device so far.
As simple as a bicycle pump, in fact, which is what inspired the designer, British engineer Alvin Smith. The newly proven system, dubbed Searaser, keeps power generation onshore – with the waterborne action confined to a pump. One end of the device is fixed by a submerged buoy tethered to the seabed. The other, which moves a piston, rises and falls with the motion of a second buoy on the surface. The two together pressurise sea water, piping it ashore. The pressure is enough to drive a turbine, or to pump water uphill for storage and later release.
After small-scale demonstrations by Dartmouth Wave Energy, Ecotricity are backing a full-scale prototype. This will cost "a few hundred thousand pounds", according to the company's founder Dale Vince, and should be ready to deploy by the end of the year.
A year's testing will follow to check flow rates, water volumes and pressures. If all the numbers are good, the company will move to a larger demonstration power plant, with onshore turbines. It will be designed to deliver under 30MW, to maximise benefits from the Government's Renewables Obligation scheme.
However, Vince believes the potential is much higher. He wants to add wave generation to the company's wind and solar installations. He believes Searaser is "the one that will make the breakthrough". He adds: "It is so wonderfully simple; it won't be difficult to optimise the engineering." Ecotricity hopes to have 200 Searasers around Britain's shores within five years, and to export the technology worldwide.
Searaser is one of the first experiments in transferring wave energy to shore before converting it to electricity to be approaching commercial use. Other candidates for this new market include the CETO system by Carnegie Wave Energy in Australia, and the Oyster device being tested in Orkney by Aquamarine Power. – Jon Turney