Aquamarine Power's Oyster marine energy generator has, at its heart, a 315kW high efficiency grid connected inverter system from Control Techniques.
Oyster comprises a large buoyant steel flap hinged to a base that sits on the sea bed. As waves roll over the device, the flap oscillates backwards and forwards, driving two hydraulic pistons attached to each side. High pressure water from these two cylinders is pumped ashore, where it drives a Pelton wheel with spoon shaped buckets that harness the energy of the high pressure water.
This is attached to a flywheel, which drives a standard induction generator. Control Techniques' inverters take the generated power and provide an interface with the grid.
Control Techniques has been involved with the development since the early stages, because of its close working relationship with the New and Renewable Energy Centre (NaREC).
"The next generation of Oyster drives, which will have three operating 'flaps', are already in development and we are looking at an output of 2.4MW per unit," says Paul Smith, Aquamarine's lead electrical engineer. "We have been very pleased with the support we've had from Control Techniques."
The units that make up the system are from the Unidrive SPM range, which can be used to implement high efficiency grid tie inverters for renewable energy systems, including wave, tidal, photovoltaic and wind.