The companies recently signed a joint venture agreement to develop the Costa Head Wave Project, to be located north of mainland Orkney, in The Crown Estate’s Pentland Firth and Orkney Waters Strategic Area. They will work together to obtain the necessary permits and intend to populate the site with AWS-III wave energy converters, a technology currently under development by AWS Ocean Energy Ltd, in which alstom acquired a 40% equity share in June 2011.
The Costa Head site is located in water depths of 60-75m approximately 5km to the north of Orkney Mainland. SSE Renewables and Alstom propose to carry out detailed site surveys and an environmental impact assessment (EIA), to develop the site with an initial phase of around 10MW, before moving on to install the full site capacity.
Established in 2004, AWS Ocean Energy is focused on the development and delivery of its AWS-III wave energy converter, a floating device with a rated power output of 2.5MW. A 1:9 scale model of the AWS-III was tested in Loch Ness in 2010. Full scale component testing will commence in 2012 with the support of the Scottish Enterprise-administered WATERS fund (Wave and Tidal Energy: Research, Development and Demonstration Support), with a full-scale prototype planned for deployment at the European Marine Energy Centre in 2014.
The AWS-III technology consists of a multi-cell array of flexible membrane absorbers which convert wave power to pneumatic power through compression of air within cells that are inter-connected. Turbine-generator sets are provided to convert the pneumatic power to electricity.
A typical AWS-III device will comprise an array of 12 cells, each measuring around 16m wide by 8m deep, arranged around a structure with overall beam of up to 60m. Such a device has a capacity of 2.5MW whilst having a structural steel weight of less than 1300 tonne. The AWS-III will be slack moored in water depths of 65-150m using standard mooring spreads. 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.