Human heart inspires wave energy system to provide green power

With the rising demand for alternative energy sources, scientists have been focusing on the forces of nature – from the sun and wind to waves and tides – to produce renewable power. Generally seen as an untapped and large-scale source of clean energy, ocean waves have been attracting a lot of attention lately.

A group of researchers supported by the EU-funded WaveBoost project have started testing a wave energy conversion system in the North Atlantic. A wave energy converter (WEC) is a device that captures the power of waves and transforms it into electricity. Inspired by the mechanics of the human heart, this new type of WEC, referred to as C3, uses a point absorber type system – a floating structure that absorbs energy from all directions through its movements at or near the water surface.

As the research team explained in a recent press release, “the C3 consists of a buoy that absorbs energy from the waves, plus a drivetrain that converts the buoy motion into electricity. The unit is based on patents by Swedish cardiologist Stig Lundbäck, some of which are inspired by his research into heart pumping and control functions.”

To validate the business case for full-scale implementation in target markets, the system is undergoing evaluation for survivability, loads and performance in off-grid operations. The system allows a large amount of wave energy to be harvested using a small device, which is robust enough to survive the toughest storms. Quoting Patrik Möller, CEO of CorPower Ocean AB, the Swedish start-up that developed the new WEC system, the press release notes that the C3 can take advantage of the full spectrum of waves. This means that it can produce five times more energy per tonne than other systems. The press release explains: “To convert the linear motion of the buoy into an energy-generating rotational motion, the system relies on a special rack and pinion gearbox developed at KTH [Royal Institute of Technology in Stockholm].”

According to Möller, once the ocean demonstration in Scotland’s Orkney is completed, the next stage is “designing, manufacturing and testing the first full-scale converter in a Stage 4 demonstration project that will run from 2018 to 2020.”

As the quest to use oceans as a renewable energy source continues, projects such as WaveBoost (Advanced Braking Module with Cyclic Energy Recovery System (CERS) for enhanced reliability and performance of Wave Energy Converters) will be more important than ever. Its objective is to provide a step-change improvement in the reliability and performance of ‘power take-offs’ (PTOs). This will involve the development and validation of an innovative braking module with a CERS. The PTO of a WEC is defined as the mechanism with which the absorbed energy by the primary converter is transformed into useable electricity. CERS is an energy redistribution system that will allow WECs to absorb more energy from high-energy wave cycles. It will temporarily store excessive energy in the first step of the PTO chain and then release it for conversion through the remaining steps of the PTO in low-energy wave cycles.

According to the WaveBoost team, by providing the extra damping needed from the CERS module, system survivability and reliability of critical components are significantly improved. Such a feature is crucial because ocean wave energy devices need to be designed with a focus on their stability and structural strength in order to capture energy while operating under extreme weather conditions.

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WaveBoost project