Scaling up low cost mechanical concepts and manufacturing for wave energy

Why is this gap important?

Wave power captures kinetic and potential energy from ocean waves to generate electricity. Wave energy converters (WECs) are intended to be modular and deployed in arrays, but at present there is little design consensus for wave energy devices with no industry-standard device concept. Due to the diverse nature of wave resources, it appears unlikely that there will be one single device concept that is used. Rather, there will probably be a small number of device types that exploit different regions of this vast resource. These concepts however need to be trialed at scale.

Technology solutions

Research in wave energy should focus on key components and subsystems, tested in a variety of conditions both separately and integrated into a whole device. While no one technique for anchoring may emerge given the variety of conditions, anchoring devices and transmission cables should be able to withstand stresses from movement of the structure and hydrodynamic forces, and installation and decommissioning need to be simplified to reduce costs.

As installation procedures also need to be simplified to keep costs down, spillover learning from offshore wind power could be helpful (e.g. in towing processes or pre-installation of structures). There could even be a sharing of offshore wind platforms, infrastructure and export cables.

Digitalisation can help scale up demonstrations and eventually production: sensing and control systems (TRL 9) can help anticipate and mitigate mechanical stresses, and big data analytics can aid in co‑ordinating turbine systems and adjusting loads on electrical equipment or generators (TRL 8), as well as predictive maintenance.

Wave energy converter power take-off systems (PTOs) (TRL 3) convert irregular low-frequency waves and swells to grid-compliant electricity. These systems require near full-scale demonstration in real sea conditions for validation. There are presently many different PTO arrangements, including turbines, hydraulic-system gearboxes and linear generators. Control systems, particularly for wave devices, will be important to ‘tune’ devices to local conditions and, in the future, to individual incident waves. Pitch control systems for tidal current blades will increase yields and survivability.

Sensing and control systems for ocean power Readiness level:

Big data analytics for ocean power Readiness level:

Power take-off systems Readiness level:

Colored bars represent the Technology Readiness Level (TRL) of each technology. Learn more about TRLs

What are the leading initiatives?

The Sotenäs project in Sweden and Wello’s Penguin prototype at the European Marine Energy Centre (EMEC) are two recent key initiatives.

In addition, two new wave energy projects are expected in Scotland by 2020: a floating hinged structure (Mocean) and a fully submerged point absorber (AWS).