Tidal turbines may need to occupy the same locations as currently used by high-density shipping. The highest stream flows are found in channels of water between large land masses, or off peninsulas where the water wants to take the same short cut as do boats or ships. There is therefore the need to allocate sea areas for each user, and it is expected that the forthcoming Marine Bill will address that.

The Resource

The world 'accessible tidal stream resource' has been put at 3% of the 3000 GW 'available' (DTI, 2002). This 90 GW (compared with a UK power capacity of 60 GW) could represent 200 TWh of energy, worldwide.

The UK has by far the best tidal current resource in Europe, estimated at between 18 and 60 TWh (5GW according to the Carbon Trust  to 16 GW according to Edinburgh University; or 5 to 16% of UK electricity demand).

Over 90% of the extractable energy contained in the top 10 UK mainland sites lies in waters 40m or more deep (The Carbon Trust). Over 50% of this deep-water resource lies in the 60m deep Pentland Firth, between Scotland and Orkney. This is the channel that helps fill and drain the northern part of the North Sea and Baltic twice a day from the Atlantic Ocean. Our estimate is that 3 million tons of water a second flows through this channel at peak times.

The European and global resources are put by the Carbon Trust to be twice and 7-10 times respectively that of the UK.

TRITON

The most powerful tidal current energy generator now in development - 10MW from a single installation

TidalStream have now completed successful testing of a six-rotor scale prototype of Triton demonstrating its versatility, stability, and opportunities for easy access and maintenance