In the updated InfinityWEC design, the power take-off (PTO) hull is divided into two halves: the upper half moves up and down with the buoy, while the lower half is fixed to the anchor. Pressure-modulated wave energy converters have used similar solutions to extract energy from pressure variations beneath the waves, near the surface. However, InfinityWEC is a point-absorption wave energy converter, with a surface buoy driving the PTO located near the seabed. At a depth of 70 m, the high water pressure provides a pretensioning force of 100 tons with a PTO hull only 1.6 m in diameter. A patent application has been filed for this innovation.
“The new pretensioning solution is a further improvement to the InfinityWEC wave energy converter, reducing the weight of the PTO by approximately 40%,” says Managing Director Mikael Sidenmark. “We harness the water pressure outside the PTO to generate constant pretensioning force, which, in combination with the ball screw actuators, provides instantaneous force control with very high efficiency. This enables wave-by-wave tuned force control, improving annual energy production by up to 30% compared to tuned control at sea.”
Ocean Harvesting is preparing for 1:3 scale sea trials of InfinityWEC, which will take place off the west coast of Sweden. The sea trial project, designed to validate performance in a real marine environment, will run from February 2023 to June 2025. The results will be used to further develop and improve the full-scale system in terms of energy performance, system efficiency, availability, and ultimately, affordability.
