Underwater kites could generate 500kW of electricity

An underwater kite aimed at generating electricity from tidal currents has received €2m of private funding to further its development.

Designed by Saab spin-out, Minesto, the system claims to be able to increase the potential energy generated from the global tidal market by up to 80 per cent.

‘The initial concept came from an idea to use kites to harness wind energy,’ explained Ted Rosendahl, chief technology officer at Minesto. ‘But as water is denser than air, we soon realised that using this system in the ocean could be far more effective.’

The kite, known as Deep Green, consists of a 12m wing, turbine, generator and rudder. Tethered 100m above the sea bed, it flies in a figure eight using the kinetic energy from the waves combined with an automatic steering system.

While a full-scale model is yet to be developed, each unit is expected to be able to generate up to 500kW of electricity which will be transmitted onshore from the generators through a power cable inside the tether.

Rosendahl said: ‘We still have some big challenges to overcome. You have dolphins and sharks in the same environment and we don’t know very much about how they will react when the see the things floating around. So testing in an ocean environment is the next step.’

The €2m of funding will be used to test a quarter scale Deep Green prototype off the coast of Northern Ireland next year. If trials are successful, Rosendahl hopes that the technology will be available on a full-scale within the next five years.