Geothermal energy
Best known for its Neolithic sites such as Skara Brae, its beef and its fishing expertise, Orkney has quietly but very deliberately become arguably the most self-sufficient community in the British Isles for its energy, and is home to many of the world's most advanced wave and tidal power machines. On Tuesday, in Orkney's second town of Stromness, that status was confirmed when Nicola Sturgeon, deputy first minister of Scotland, announced the world's most lucrative renewable energy competition: the £10m Saltire prize challenge.
Four marine energy firms have entered their wave- and tide-powered devices.
There is the Pelamis P2 "sea snake", a long, jointed device that harnesses energy by undulating with the waves off Sutherland; Aquamarine Power's Oyster 800, in which a large flap catches the waves' power off the Western Isles; MeyGen's tidal energy scheme in the powerful waters of the Pentland Firth, off Caithness, using underwater propellers anchored to the seabed; and ScottishPower Renewables, with scores of similar tidal turbines off Caithness. To win the Saltire prize, these machines must produce at least 100 gigawatt hours of electricity over a continuous two-year period between now and 2017. So far only four tidal- and wave-power devices being tested at the European Marine Energy Centre (Emec) at Stromness have produced electricity for sustained periods. Even then, that was over a matter of days, not months.
There is scepticism within the renewables industry about the purpose of the Saltire prize: the costs of entering it far outweigh its value. The real goal for the renewables industry is so obvious – to harness the immense energy of the sea, and tap into a global market predicted to be worth £1tn – that its existence changes little.