It is the world's first marine renewable energy system of significant size to be installed in a genuinely offshore location and, as such, marks the stage at which the technology for exploiting marine energy has moved into the harsher energy rich environment in which it needs to operate.

The turbine is the culmination of the £3.5m 'Seaflow' Project being conducted by a consortium of UK and German companies and supported by the British Government's Department of Trade and Industry, the European Commission's Joule Programme, and the German Government.

The project is aimed at testing the prototype turbine and demonstrating technology which will be further developed to a commercially viable stage by Marine Current Turbines Ltd (MCT) of Basingstoke, Hampshire, UK over the next few years.

The technology consists of rotors mounted on steel piles set into a socket drilled in the seabed. The rotors are driven by the flow of water in much the same way that windmill rotors are driven by the wind, the main difference being that water is more than 800 times as dense as air, so quite slow velocities in water will generate significant amounts of power.

The Seaflow Project, in effect, involves the design, manufacture, installation, testing and demonstration of an 'Underwater Windmill' which can generate a maximum of 300kW in a 2.7m/s current (5.5 knots). The tide derived energy generated has the additional advantage of being totally predictable. This device will provide the essential information needed to design and build larger systems for commercial power generation, which is expected to follow over the next few years.

Maintenance of the device while it is submerged in fast currents would be exceptionally challenging and expensive, so a key patented feature of the technology is that the rotor and drivetrain (ie, gearbox and generator) can be raised completely above the surface.

Once raised, maintenance or repairs can be readily carried out from the structure attended by a surface vessel.

The industrial consortium working on the Seaflow Project is made up of Marine Current Turbines, which developed and owns the technology; Cornwall UK based specialist offshore engineers Seacore Ltd; Carlisle UK based precision steel fabricators Bendalls Engineering;

I T Power Ltd, Basingstoke UK based renewable energy engineering consultants; steel supplier Corus UK Ltd;

Germany's ISET eV, a spin-off company from the University of Kassel specialising in electrical power and control; and Jahnel Kestermann GmbH, which manufactures marine and wind turbine gearboxes.

Two key subcontractor companies are consulting engineers W S Atkins, who have seconded a senior engineer to MCT, and Aviation Enterprises Ltd, whose aircraft expertise enabled the development of an innovative and advantageous carbon and glass fibre reinforced composite rotor design for the project.

MJ Information No: 18405