InfinityWEC ready to materialize in Sweden

InfinityWEC wave energy device (Image: Ocean Harvesting Technologies)

Swedish wave energy developer Ocean Harvesting Technologies has completed the system design for a full-scale device named InfinityWEC ahead of planned two-year test and demonstration project.

The InfinityWEC machinery will be first tested on a half-scale Hardware-In-the-Loop (HIL) test rig by the Research Institute of Sweden (RISE) within the SMART-Ocean and Test Site Skagerrak Initiative – a new test site being established on the west coast of Sweden, according to Mikael Sidenmark, CEO of Ocean Harvesting.

Hoping to start with the project in September 2018, the company is currently in the process of raising funds by applying for grants to the EU’s Horizon 2020 SME Instrument program, and to the Swedish Energy Agency, to support the planned two-year test and demonstration of the system.

The project includes detailed design, build and test of the InfinityDrive power take-off (PTO) and ball screw actuator systems, using HIL rig setup integrated with Ocean Harvesting’s wave-to-wire simulation model in WEC-Sim to provide realistic interaction between the wave energy converter (WEC) and waves.

The overall purpose of the project is to qualify the WEC machinery for sea trial in a complete InfinityWEC system, and to demonstrate the technology for industry stakeholders, according to Sidenmark.

“The InfinityWEC is the result of 10 years of innovation, research and development with a special focus on the integration of energy storage in the PTO in a way that improves both power capture and power quality.

“We believe that the InfinityWEC will be very competitive to offshore wind power, offering lower cost of energy already early on after a commercial launch, providing more than 20 times higher capacity per used sea area, having virtually no visual impact and outputting a more stable power with less intermittency,” Sidenmark said.

Main parts of the Infinitely Variable Transmission system in the InfinityDrive PTO (Image: Ultimate Transmission)

The InfinityWEC uses a ball screw actuator system with integrated level adjustment, and a mooring pipe system with a fixed PTO position that eliminates the frequent bending of the power cable from the wave cycles, Ocean Harvesting claims.

In 2017, the company discovered the opportunity to use an infinitely variable transmission (IVT) in combination with a flywheel energy storage, to provide advanced PTP force control features and constant power output.

The technology is similar to Kinetic Energy Recovery Systems (KERS) used in vehicles to recover brake energy, but with a high-speed generator connected to the continuously rotating flywheel to output constant electricity, according to Ocean Harvesting.

The technology has been named InfinityDrive PTO and is the central piece of the InfinityWEC device.