Tidal stream power is the process of converting the kinetic energy of flowing tidal streams into useable power in the form of electricity. Tidal streams are typically found in channels between islands, around peninsulas, or in bays and estuaries. The UK has a significant tidal stream resource which represents around half of the European resource and between 10-15% of the known global resource (UK Tidal Stream Energy Resource Assessment, Black & Veatch, 2005). The latest estimate of the total UK resource is 18TWh/y, with the global resource estimated in the region of 180TWh/y.

Some of the best tidal sites in the UK are located on Scotrenewables' doorstep in the channels around the Orkney islands and the Pentland Firth, between Orkney and the Scottish mainland