Wave power generators generally take the form of sea snake-like designs that sit atop rolling waves, gathering kinetic energy and turning it into power. However a new idea combines the worlds of wind power and wave power to create underwater kite-turbines. Designed by Swedish renewable energy company Minesto, each underwater kite spans 8-14 meters and features a turbine attached to its underbelly. Each kit is tethered to the sea floor and it can “fly” with the tidal stream in a figure-8 motion.
Working under the same principles as the Seagen Turbine (pictured above), the kite-turbine’s blades are turned by the movement of passing tides. But the swooping motion of the kites amplify the speed of the water flowing through the turbine 10 fold – similar to the way sail boats gather speed by cutting across the wind. Furthermore, the kite has neutral buoyancy, so doesn’t sink as the tide turns, and the turbine mouth is protected to keep fish from flying through.
Ander Jansson, Minesto’s managing director, told the Guardian that the kite should work in flows of 1 – 2.5 meters per second, while first-generation devices need over 2.5 meters per second. Depending on the location and size of the kites, each will have a capacity of between 150 and 800 kW, and be deployed in waters 50-300 meters deep. The technology’s first test at Strangford Loch, Ireland will be at one-tenth scale.
Over the next 18 months the UK Carbon Trust and Invest Northern Ireland will spend $564,000 to fund trials as the UK strives to meet its ever-more ambitious environmental goals. Harnessing the power of the ocean presents many challenges, not least the economic cost. Two turbines with a combined capacity of 1MW could cost over $3m, and commercial viability will rely heavily on economies of scale.
Check out the video below to see just how Minesto aims to capture the awesome power of the sea.