The station, known as LIMPET (Land Installed Marine Powered Energy Transformer), began supplying the island’s grid with 500 Kilowatts, enough to supply about 400 homes, on 20 November. The station was jointly developed by WAVEGEN, world leading wave power developers, and Queen’s University Belfast with EU support and has secured a 15 year power purchase agreement with the major public electricity suppliers in Scotland.

The £1 million LIMPET was born out of a 10-year research project on the island where the team had built a demonstration plant capable of generating 75 Kilowatts of electricity. The station consists of a wave energy collector and a generator. The energy collector comprises a sloping reinforced shell built into the rock face on the shoreline with an inlet big enough to allow seawater to freely enter and leave a central chamber. When waves enter the shell chamber, the level of water rises, compressing the air in the top of the chamber, which is then forced through a ‘blowhole’ into the ‘Wells Turbine’, named after the designer Professor Alan Wells of Queen’s University in Belfast. The turbine has been designed to continue turning the same way irrespective of the direction of the airflow. As the water inside the chamber recedes when the waves outside do, the air is sucked back under pressure into the chamber, keeping the turbine moving. This constant stream of air in both directions, created by the oscillating water column, produces enough movement in the turbine to drive a generator which converts the energy into electricity.

Wavegen says that the system lasts for sixty years, requiring minimal maintenance, and has a high level of reliability. The company argues that there could be sufficient recoverable wave power around the UK to generate enough power to exceed domestic electricity demands, and that LIMPET has opened the door for wave power to become a major contributor of renewable energy. Alternatively, LIMPET units may be incorporated within rubble mounds or caisson breakwaters to provide self-financing coastal protection schemes, providing power or potable water to local communities.

“Wave power has joined the important group of commercially viable, competitive and clean forms of sustainable energy; this is the launch of a new global market,” commented Allan Thomson, Managing Director of Wavegen.

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