Telegraph: Tidal power has been harnessed to generate electricity for Britain’s National Grid for the first time, it has been announced. The move has been hailed as a milestone in the development of marine energy, which could provide up to a fifth of Britain’s electricity needs. It came when a single turbine on the Atlantic seabed off Orkney was connected to the National Grid on Monday morning. The area off the north of Scotland is regarded as potentially one of the best in the world …