Scotland's first commercial-scale tidal turbine has been connected to the electricity grid off the Orkney coast and begun generating power. Tidal turbines harness the energy provided by the movement of the tides and supporters say they will provide a predictable, reliable source of green electricity.
The gigantic machine which resembles an underwater wind turbine weighs 1,500 tonnes and stands 70 feet off the seabed and will generate enough electricity annually to power about 1,000 homes. Hundreds of these machines could be installed in the turbulent waters of the Pentland Firth off Scotland's north coast. 400 of the turbines in the Inner Sound tidal site in the Pentland Firth, behind the island of Stroma and the mainland would provide enough electricity for about 400,000 homes.
However, questions remain about the impact of tidal renewable energy on marine life.