A pioneering energy project was quietly launched off the Devon coast this week. The biggest underwater tidal energy turbine so far has been built into the seabed a mile offshore near Lynmouth. Most of the structure of the turbine is piled into the seabed and so from the coastline the project is almost invisible.

The single 11 metre-long rotor blade of the turbine will be capable of producing 300 kilowatts of electricity and is designed as a test-bed for further tidal turbines. A further blade is to be added shortly.

Project developers Marine Current Turbines Ltd and Cornwall-based Seacore expect to have the turbine connected to the national grid by the end of August.

Rather than trying to capture the energy in the tides via large expensive and environmentally invasive barrages across estuaries, the idea of using tidal currents is being explored.

Although practically unnoticed, the world's potential marine current resource is enormous, and it could provide a sizeable proportion of the world's energy needs if developed on a large scale.

Tidal flows in the oceans are regular, predictable movements of huge volumes of water. Fast currents can be generated where islands and coastal features constrict these flows, and these can be exploited economically. Marine current technology extracts the kinetic energy from the moving water, and differs from tidal barrages, which rely on the rise and fall of the tide.

The tidal modelling and marine current turbine optimisation project is jointly funded by the European Commission and the Department of Trade and Industry.

The concept can become a rival to wind power because ocean currents are more reliable than wind and also because they are less obtrusive. The structure is built on the seabed and projects just a few metres above the surface.

The Lynton and Lynmouth area is one of the most beautiful and unspoilt coastlines in the country and initial concerns by the public were allayed by an environmental impact study, which showed not only would the project have little visual impact, but that the fishing would be undisturbed.