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An “underwater kite” tidal turbine has been developed that opens up the possibility of more coastal areas being used for energy generation across Britain in the remainder of the decade.
The Deep Green technology works like a kite and is tethered to the seabed by high-strength composite materials. When the tide comes in it lifts up the device, allowing it to move back and forth through currents underwater, generating energy.
Developer Minesto hopes to see the first grid-connected device up and running in 2013. A 10MW array could follow in 2015.
Anders Jansson, managing director of Minesto, said: “It can sweep a very large area with very little material, so we have a very small and cost efficient power plant.”
Rudders on the device control the movement of the turbine so that it moves through the water in a figure-of-eight shape. This accelerates the speed of the water entering the turbine by up to 10 times – which means it can operate in slower currents than other tidal energy technologies, Minesto said.
Minesto said this could lead to a step change reduction in the cost of tidal energy. The company aims to open up new areas of low-velocity tidal streams around the UK for power generation.
The Carbon Trust has given Minesto a £350,000 grant to deploy the first seagoing prototype of the device later this year. The device will be trialled off the coast of Northern Ireland in an eight-month project from August. Stephen Wyatt, research and development manager at the trust, said: “Minesto’s technology effectively extends the amount of tidal resource in the UK. In areas that were previously not viable for conventional technology, the Minesto device could open these up for what could potentially be cost-effective energy generation. The whole of the Irish Sea could be a viable tidal energy site.”
Jansson said that the turbine addressed a niche market and did not compete with more conventional forms of tidal turbine, such as horizontal-axis types. There is also the potential for larger versions of the device to be made and bigger tidal farms or arrays to be developed in the future.
“As long as we have the space and the tides there really is no limit on how many devices we can put into one array,” he said.