Scottish Power plans worldÂ’s largest tidal farm

Three sites are under investigation - two off Scotland and one off the coast of Northern Ireland - for up to 60 underwater turbines, generating 60 MW of power for 40,000 homes.

Scottish Power, the energy firm behind the plans, said the technology could make Scotland a global leader in the field.

Director of the firm's renewable arm Keith Anderson said: "This is a historic day for the development of marine energy.

"The rapid technological advancement of tidal power has enabled us to progress plans for this substantial project which has the real potential to deliver significant environmental and economic benefits."

The announcement came as the Crown Office opened parts of the seabed for leasing to developers. The tide-turbines are expected to be weighed to the floor of the sea in the Pentland Firth between the Scottish mainland and Orkney, in the Sound of Islay and off the coast of Country Antrim, Northern Ireland.

The structures stand 30 metres tall on three legs and can work as deep as 100 metres below sea level with the ability to turn to harness tide movements. The 20-metre blades would turn at least 10 metres below the surface to avoid shipping, developers said.