Technology

Practical, affordable wave energy

At AWS we have a clear purpose. We will develop and deliver the technology of choice for utility scale generation of offshore wave power. We are driven by finding solutions to all of the challenges present in creating a practical affordable wave energy device and approach this in an evolutionary manner. Our strategy is endorsed by Alstom, our major OEM backer and contrasts with that of other developers who doggedly pursue a single invention no matter how obvious the flaws.

The result of this approach is the AWS-III: A multi-cell array of flexible membrane absorbers which covert wave power to pneumatic power through compression of air within each cell. The cells are inter-connected, thus allowing interchange of air between cells in anti-phase. Turbine-generator sets are provided to convert the pneumatic power to electricity.

A typical device will comprise an array of 12 cells, each measuring around 16m wide by 8m deep, arranged around a circular structure with overall diameter of 60m. Such a device is capable of producing an average of 2.5MW from a rough sea whilst having a structural steel weight of less than 1300 tonne. The AWS-III will be slack moored in water depths of around 100m using standard mooring spreads.

Visualisation of an AWS-III farm at sea on a calm day

Devices will be arranged in arrays or ‘farms’ of up to several hundred MW total rating. Each AWS-III will be connected to a central offshore substation via a high-voltage umbilical link.

The AWS-III is designed for practical operation and maintenance by utility power generators. The large, stable vessel structure provides a safe environment for on-board maintenance of generation equipment and ancillaries whilst our patented system for cell maintenance allows rapid exchange of the flexible wave absorber cells.

We do not make wild claims about cost of energy. What we will say however is that the AWS-III has a power to weight ratio double that of any other offshore wave energy device. It has no exposed moving parts and uses simple, proven power take-off technology and is designed for practical maintenance – key factors for high availability. Device scale mans that fixed costs such as moorings and power umbilicals are lower per MW installed. With these features we are confident that AWS-III farms will represent an investable proposition for utilities under the current 5-ROC wave energy tariff for projects in Scottish waters.