New wave-power technology doubles the energy extraction

A new type of wave-power technology will be tested next year and evaluated in a marine environment – in the waves off the coast of Norway. A doubling of the energy extraction, a balanced energy production and a halving of the electricity generation cost for wave power is the objective.

Ocean Harvesting Technologies AB has been awarded SEK 4.8 billion in support from the Swedish Energy Agency to manufacture and, in a marine environment, test and verify the performance of its prototype for wave energy conversion.

Existing concepts for energy extraction from waves frequently employ hydraulics to achieve a balanced electricity production. The problem with hydraulic solutions is that they cannot make use of all the energy that is contained in large waves. Ocean Harvesting Technologies instead uses a mechanical equalisation system to be able to extract energy from even the largest waves.

"Different wave climates require different techniques. This project is a step in broadening our investments in marine energy technology at the same time as we promote Swedish environmental engineering," says Angelica Pettersson from the Swedish Energy Agency.

More balanced electricity production

The prototype is envisaged to give a more balanced electricity production by means of an equalisation principle with a plumb that stores potential energy from the waves, referred to as constant power accumulation. The generator works constantly when the plumb moves in time with the wave movements, and at the same time reduces the wastage of energy that occurs within the usual hydraulic solutions for wave power.

By being able to utilise large waves as a result of the plumb that stores energy, the technique is considered to be capable of achieving an efficiency level of 65 per cent in good wave conditions, compared with about 30-35 per cent in existing, mostly hydraulic systems.

Thanks to the high efficiency level, it is considered possible to halve the cost of electricity production compared with corresponding wave power techniques. The technique incorporating a transmission solution is judged to be of interest for other wave power developers in Great Britain and other parts of the world.

"Thanks to the support we've received from the Swedish Energy Agency, we now have the chance to demonstrate that our technique works offshore. The test will also give us important data for further development of the technique," says Mikael Sidenmark, Managing Director of Ocean Harvesting Technologies AB.

The prototype will be tested in the sea off Risör in Norway during 2013.