A major tidal energy project is being planned for waters off the coast of Scotland and Northern Ireland.
Scottish Power has identified the Pentland Firth, Sound of Islay and Antrim coast to test sea turbines which could power thousands of homes.
It comes as Scotland's first minister, Alex Salmond, visited the far north and the Crown Estate opened up the Pentland Firth seabed for leasing to developers.
Projects on the firth could be operational by 2020.
The sea off the Caithness and Sutherland coasts and around Orkney have been identified by the Crown Estate as having potential for generating energy.
Mr Salmond said the firth could be seen as "the Saudi Arabia of marine energy".
Scottish Power has been working on the Lanstrom device, which is said to be the world's most advanced tidal turbine.
How the tidal turbine works
The Scottish and Irish sites would host up to 60 of the turbines - 20 at each site - generating 60 megawatts of power for up to 40,000 homes.
The company is expected to apply for planning permission next year.
The device, similar to an underwater wind turbine, has been tested in a Norwegian fjord.
Scottish Power insists there is no threat to marine life, but the Marine Conservation Society said it would want to look closely at the proposals and see a rigorous environmental impact assessment.
LANSTROM TIDAL TURBINES
Turbines stand 30m tall on three legs and can work as deep as 100m below sea level
Ability to turn to harness tide movements
Turbine zones would be banned to trawlers for safety reasons
The director of Scottish Power's renewable arm, Keith Anderson, said: "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."
Speaking during his visit to Caithness, Mr Salmond said opening the firth for energy generation on a commercial scale was "exciting news" for Scotland's renewables sector, environment and economy.
He said: "These developments are a significant step forward in Scotland's journey to become a world leader in the development of renewable energy."
Mr Salmond added: "The Pentland Firth is the Saudi Arabia of marine power.
"Our seas alone could provide 25% of Europe's tidal power and 10% of wave power. The vast potential of the Pentland Firth will mean more investment, more jobs and more opportunities for the Caithness area."
Generating power from the sea could also be key to supporting the far north economy as jobs are reduced at Dounreay, a former nuclear power complex.
The first minister joined 150 delegates and representatives from about 20 marine energy developers at the Caithness Regeneration Conference.
Creating work in the area has become increasingly important because of the decommissioning of Dounreay.
The Thurso conference - taking place for the second time - will discuss progress on an action plan drawn up to steer the region through the effects of the plant's wind-down and eventual closure.
Highlands and Islands Enterprise (HIE), Highland Council, the Nuclear Decommissioning Authority, Scottish Government and local community are involved in the project.
Eann Sinclair, of Caithness and North Sutherland Regeneration Partnership, said: "Proposals are under way for projects such as the Pentland Firth Tidal Energy project and the development of Scrabster and Wick Harbours, as well as the creation of new jobs in the engineering sector."
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