CorPower Ocean of Sweden has unveiled its first commercial-scale wave energy harvester and a concept for supporting wind turbines.
The harvester, dubbed C4 and rated at 300kW, will ultimately form part of HiWave-5 Project, a wave array off the coast of Aguçadoura, Portugal.
The buoys are 19m tall and 9m in diameter.
Inside the thin buoyant structure (see cross section left) is a vertical column guyed to the sea bed, up and down which the floating part slides. For scale, the yellow parts inside are human walk ways.
The column is complex: its bottom half is four rods going outside the structure downwards to the guy line, while the top half is a fat hollow cylinder (white). At the join is the generator (grey box) which works against the relative motion of a fifth, coaxial, rod that is attached to the inside bottom of the float – the reason the top half of the column is hollow is to accommodate this rod when the float is in its high position, as it is in the diagram.
Generators are geared to this relative motion, so they rotate one way and then the other as the float bobs on the waves.
Structurally, internal tension elements increase the rigidity of the hollow shell.
The bane of wave power is storms, which have destroyed many otherwise promising wave power harvesters.
Against storms, the C4 has a system of adjustable dampers (forming a grey ‘V’ in the diagram), that are tuned to extract maximum power most of the time, but re-tuned to minimise the chance of damage during heavy weather.
C4s are designed to be delivered as ‘CorPack’ clusters rated at 10-20MW rating, which are intended to be the building blocks of large-scale wave farms. They are also intended to offer “plug-and-play compatibility with offshore wind infrastructure”, according to the company.
“This has been a decade-long development, with significant strides in the last few years to industrialise and optimise our wave energy technology,” said CorPower CEO Patrik Möller. “We are on track to deliver certified and warrantied wave energy products to the market by 2024/25.”
CorPower is also working, with Simply Blue Group, on a pre-commercial wave farm off Ireland’s west coast called Project Saoirse.
“This is a really exciting phase in the movement towards hybrid wave-wind farms as we aim to harness the immense power of the Atlantic Ocean, combining floating offshore wind and wave technology to produce zero-carbon electricity,” said Simply Blue Energy CEO Sam Roch-Perks.
To date, CorPower Ocean has been financially supported by EIT InnoEnergy, the European Commission, the Swedish Energy Agency, AICEP Global (Norte2020), Wave Energy Scotland, CoreSpring New Technology, ALMI Invest Greentech, SEB Greentech VC and additional private investors.
This video (scroll down) explains how the CorePower C4 buoy works operates
