The sea is a harsh environment for machinery, and working at sea is expensive. Nevertheless, a number of industries do work successfully in marine environments, and have a great deal of experience in making reliable, cost-effective, marine equipment. The recent development of offshore wind generation is particularly relevant for marine current turbines. IT Power has been working on current turbines for a number of years and its work is showing that recent technological advances can be applied successfully to marine current turbines.
Researchers in a few countries, such Canada, Japan, and Russia have tested small, prototype units producing a few kilowatts. The Australian Tyson Turbine is a commercially available unit, but this is a stand-alone generator producing only 3 kW, primarily designed for fast-flowing rivers rather than the sea. IT Power designed and tested a 15 kW current generator at Loch Linnhe in Scotland, working with Scottish Nuclear and NEL Ltd. This used a 3.5 m diameter rotor on a pod containing a gearbox and generator. The unit was suspended 5 m below the surface from a buoy moored to the seabed. This "proof-of-concept" project showed that it was possible to generate power from tidal flow, and gave valuable experience of working the difficulties of working in offshore conditions.
It now seems time to implement tidal turbines on a commercial scale. The EC has just given funding to a consortium headed by IT Power to design and install a 300 kW tidal turbine off the coast of UK. The IT Power/EC "SEAFLOW" R&D project will adapt equipment and designs from marine, offshore, and wind-generator technology to prove that current turbines can be made and installed at reasonable cost. It is planned to install the turbine in the year 2001, and it will supply electricity to the grid over a period of at least a year to give operating experience.