InfinityWEC – at the forefront of wave power technology

InfinityWEC is a novel point absorbing Wave Energy Converter (WEC). It is both highly efficient in capturing energy through its ability to adjust to the sea state, and robust enough to operate reliably and survive the harshest marine conditions. Cost efficiency is further improved by its modular design and the easy handling, allowing for road transportation and requiring a minimum of offshore operations.

InfinityWEC uses advanced reactive force control technology to tune the system to capture the optimal amount of energy in every wave, which greatly increase the annual output. A two-stage end-stop handling system holds the buoy submerged through the crest of large waves and then returns the system to normal operation, protecting the system from excessive forces and allowing energy to be produced even in the most severe wave conditions.

The system is installable with a minimum of complicated offshore operations and no diving or heavy lifting are necessary offshore.

The InfinityWEC technology and design is patent pending and developed by Ocean Harvesting Technologies AB in collaboration with experienced partners.

How it works

Advanced reactive force control on the buoy is provided throughout the full wave motion, which greatly amplifies the energy output and minimizes cost by limiting loads.

Direct drive ball screw actuators in combination with a hydraulic pre-tension spring system provide highly efficient PTO force control capability at a low cost.

• The waves lift the buoy, together with the pre-tension cylinder and the ball nuts attached to it with the upper mooring rope.

• The pre-tension cylinder is connected to a piston accumulator with a large gas volume and applies a constant spring force, providing half of the available PTO control force.

• The vertical motion of the ball nuts causes the ball screws in the PTO hull to rotate, driving the frameless torque motors (generators) directly connected to the ball screws.

• Variable Frequency Drives are used to apply bi-directional torque up to ± 50% of the available PTO control force, enabling instant stepless control from 0 – 100% together with the pre-tension spring.

• A second hydraulic cylinder below the PTO hull adjusts the position of the PTO hull to the tidal variations.

How it survives

InfinityWEC does not have a survival mode where power production is shut down in strong sea states, instead it uses a passive survival strategy allowing power to be produced in every wave.

A novel two-stage end stop cushion system holds the buoy submerged through the crest of large waves.

• The first stage is a cushion in the pre-tension cylinder, which increases the cylinder force to stop the motion of the heave system just before the end of stroke.

• The second stage of the cushion is a hydraulic spring in the level cylinder, allowing the PTO to be pulled up along with the buoy up to about 2 meters until the motion stops and the buoy is held submerged through the crest of large waves.

• After a submerge event, the PTO is returned to its previous position by the hydraulic spring, making the system ready to capture power in the next wave.

• The two-stage end stop cushion reduces the required control force and stroke length of the heave system, and stops the buoy motion with a low deceleration force.

• This greatly reduces the cost of the InfinityWEC and improves the energy output and reliability.

Advantages of InfinityWEC

Solving the challenges of wave energy

Our technology has the potential for cost effective electricity generation to main power grids, as well as to off-grid applications.

• Through our advanced power take-off and force control technology, we achieve high energy output at low cost.

• The passive two stage end-stop cushion system protects the system from excessive forces and enables power to be produced also in the harshest conditions.

• Through energy storage we address the challenge of ensuring a constant and predictable power output despite the high short-term variability in wave power generation.

• The system is modular and suitable to produce in large scale, and is also made from parts and materials that can be easily transported and assembled on any location.

• Our technology has the potential for electricity generation for main power grids as well as for off grid applications such as isolated areas, island communities, oil & gas platforms and fish farms.

• Only proven technologies from other industries are used and integrated in the InfinityWEC system, enabling fast and capital efficient route to market.

• Wave energy requires less than 1/10 of the area needed for wind power, due to the higher energy density in waves compared to wind, and can be placed much closer to the shore-line, since the visual impact is virtually zero.

• The estimated LCoE is highly competitive to wind and solar energy at 100 EUR/MWh already at 100 MW deployed capacity, and 35 EUR/MWh at GW scale deployment.

Road map

We follow the staged development method set out by the international marine energy community

OHT is since 2017 developing the novel InfinityWEC wave energy converter with advanced force control and with AI capabilities. We have an extensive know-how in the wave power application and patent protection covering all aspects of the InfinityWEC system. To mature the concept we have developed tools to accurately assess dependencies between design and the overall life cycle cost of the system. We believe in using numerical models to time and cost efficiently simulate the behavior, loads and performance of the system, and to verify them with limited and controllable physical tests. This ensures we are on track to a commercially viable system before we move into large scale prototypes and testing.

We are currently in the design and validation phase of the InfinityWEC technology, building a scale 1:10 of the InfinityWEC power take-off system, to be tested in a hardware-In-the-loop (HIL) test rig. This enables us to simulate authentic load conditions in a controlled dry environment.

In 2022 we plan to conduct sea trials with a fully operational InfinityWEC in approximately scale 1:3.

In 2024 we plan for sea trials with a full scale 500kW InfinityWEC after which our system is validated and certified.

In 2025 we plan for our first commercial installations.