20'000 watts under sea

However, the Swedish company Minesto has come up with a highly innovative solution to this technological challenge. They design lightweight, invisible, non-polluting and highly efficient devices.
Power of the future?

Back in 2001 Magnus Landberg, working in Saab’s aeronautics department, was charged with studying the design of carbon fibre wind turbines. After some efficiency calculation, he had another idea: what if, instead of using wind energy, we designed an underwater kite attached to a turbine capable of making use of the currents?

Mind you, the ocean is a tremendous source of energy. Every day, the force of gravity of the Moon, the Sun and the Earth’s rotation provoke an extraordinary powerful ebb and flow: tides. This extraordinary water movement is being harnessed by Deep Green, the revolutionary solution invented by Magnus Landberg, being now further developed by Minesto, the com- pany born of the project.

At first sight, Deep Green looks like a toy. Fastened to a foundation on the seabed by a tether, its carbon fibre wing follows the current and, just like a kite flies faster than the wind, it can reach a speed 10 times higher than the water current.

Carried by the wing, a turbine transforms this mechanical energy into electricity, which con- tinues in sub-sea cables to the shore and the network. The device is fitted with LEMO’s underwater connectors for signal control.

Extremely lightweight, Deep Green is incredi- bly cheap and hightly efficient. The system can function with velocities as low as 1 to 2.5m/s. Moreover, sea water density being 800 times higher than air density, the device can poten- tially produce 800 times more energy than a wing used in air. Compared to wind turbines, the numbers are easy to calculate: Deep Green is 16 times more efficient. Since tides are a con- stant phenomenon, it never stops working.

Minesto also offers key environmental assets. Whereas wind turbines transform the land- scape and nuclear plants are criticized because of the danger and waste, Deep Green is par- ticularly eco-friendly. Underwater, it is invisible from the coast. Installed far from fishing zones, it doesn’t disturb the fauna and flora that adopt the structure rapidly as artificial reef, once it is “anchored”.

Obviously, installation requires a fairly long preparation. You need to identify the ideal geographical area – not too far from the coast, so that electricity can rapidly reach the power network. Since the ocean is a very demand- ing environment, it is critical to have highly resistant material and components to ensure a 20–year life cycle without frequent replacement.

Despite the challenges, Deep Green has a promising future. Winner of the 2014 “WWL Orcelle Award”, rewarding highly innovative solutions in the field of environmental tech- nologies, Minesto is riding on a wave of suc- cess and keeps generating interest all over the world. Following a first installation in Northern Ireland, Minesto has been working on projects in Wales, in Japan, in Chili and soon in the USA.