Search: go

Marine Renewable Energy

Devices

Marine renewable energy is an emerging market, and there are a range of different prototype technologies being developed or installed. We've collected examples of the main devices below to explain how they use natural power to generate electricity.

Details about what stage of development different technolgies are at can be found on our main devices page.

Marine Current Turbines

Seaflow is a 2 bladed rotor connected to an electrical generator mounted on a steel mono-pile drilled into the seabed. The blades turn in the tidal stream (like wind turbines are driven by wind) and the greater density of water means that although the blades are smaller and turn more slowly, they still deliver a significant amount of power.

Pelamis

The Pelamis Wave Energy Converter consists of several large, floating cylinders connected by a hydraulic system. As waves pass under the device the cylinder joints pivot and move hydraulic rams, pressuring oil and storing potential energy. This high-pressure oil is released through hydraulic turbines, driving generators inside the device. Pelamis has 3 250kw generators.]

SMD Hydrovision

TidEL consists of two turbines mounted on a buoyant crossbeam. A full scale device would consist of 15m diameter blades driving two 500kW generators. The unit is buoyant and tethered to the seabed, allowing it freedom of movement. The turbines can automatically align themselves down-stream of the tidal flow as it changes during the day.

Stingray

Stingray uses a hydroplane, similar to an aeroplane's wing but in water, to collect energy from the tide. This is attached to a mechanical arm which changes the position of the hydrofoil each cycle, and is also connected to a pump which pressurises oil. This oil passes through a hydraulic turbine which drives a generator to produce electricity. Stingray is a seabed mounted machine, designed for use in water up to a depth of 100m.

Oscillating Water Column

Limpet, on the coast of Islay in the Highlands of Scotland, is an onshore Oscillating Water Column (OWC). Waves surge into a chamber open to the sea and force air through a Wells turbine, which can generate power from air flowing in either direction. As the waves recede, air is drawn back into the chamber via the turbines, generating more power. Rated at 0.5MW, this device has generated power for the local grid since 2000.