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Low-cost wave power device set to transform marine energy industry

Company says device which harnesses power from ocean swells will have lower costs than any form of conventional energy

Searaser will harness low cost energy from ocean swells
Searaser will harness low-cost energy from ocean swells

UK green energy firm Ecotricity is developing a low-cost wave power device using technology which is believed to transform the marine energy market. The device, called Searaser, harnesses energy from ocean swells by pumping seawater using a vertical piston between two buoys.

One buoy is on the surface of the water, the other is suspended underwater and tethered to a weight on the seabed. As the ocean swell moves the buoys up-and-down the piston pumps volumes of pressurised seawater through a pipe to an onshore turbine to produce electricity.

This opens up the additional option for Searaser units to be used to supply energy on-demand. By pumping seawater into coastal storage reservoir, it can be released through a generator as required. This means not just energy is made from the sea, but energy that can be turned on and off, as required.

Ecotricity founder Dale Vince, said: “Our vision is for Britain’s electricity needs to be met entirely from the big three renewable energy sources: the wind, the sun and the sea.

“Until now, the sea has been the least viable of those three energy sources and we believe that Searaser will change all of that. Indeed we believe Searaser has the potential to produce electricity at a lower cost than any other type of energy, not just other forms of renewable energy but all ‘conventional’ forms of energy too.”

The company says the system will go a long way to solving the problem of renewable energy’s naturally intermittent output on the UK’s electricity grid, as well as the issue of cost. It says these issues are two of the biggest barriers to the deployment of renewable energy on the scale the UK needs.

Inventor Alvin Smith said the main barrier to making wave-power efficient and therefore cost-effective is resilience against the hostile ocean environment.

He said: “Most existing wave technologies seek to generate electricity in the sea itself. But as we know water and electricity don’t mix – and seawater is particularly corrosive – so most other devices are very expensive to manufacture and maintain. But Searaser doesn’t generate the electricity out at sea. It simply uses the motion of the ocean swell to pump seawater through an onshore generator.”

Vince said Ecotricity’s investment will drive the next phase of Searasers' development, by having a commercial scale Searaser in the sea within 12 months and 200 Searaser units around the British coastline within five years.

Vince said: “The potential is enormous. This is a British invention that could transform the energy market not just here in Britain but around the world. Our plan is to develop the technology and make them here in Britain, bringing green jobs as well as green energy to our country.”