A company called Marine Current Turbines will be installing a 1.2 megawatt tidal turbine in Northern Ireland's Strangford Lough in August. The SeaGen turbine will be the world's largest ever tidal current device by a significant margin. It will generate clean electricity for approximately 1000 homes. The turbine is a prototype to be replicated on a large scale over the next few years. The rotors on the SeaGen turbine turn slowly: about 10 to 20 revolutions per minute. A ship's propellers, by comparison, typically run 10 times as fast. The risk of impact from SeaGen rotor blades is small, because the marine creatures that swim in strong currents tend to be agile, and can avoid slow-moving underwater obstructions.
Future turbines will generally be rated at from 750 to 1500 kilowatts (kW), and will be grouped under the sea, at places with high currents, in much the same way that wind turbines in a wind farm are set out in rows to catch the wind.
Commenting on the future prospects for tidal current energy, Martin Wright, Managing Director of Marine Current Turbines said: "We will build on the success of SeaGen to develop a commercial tidal farm, of up to 10MW in UK waters, within the next three years. With the right funding and regulatory framework, we believe we can realistically achieve up to 500MW of tidal capacity by 2015 based on this new SeaGen technology."
See also: TreeHugger Picks: Wave and Tidal Power