Norway's Statkraft optimistic on marine current turbines

Norwegian firm Statkraft says subaquatic sea tide-harnessing machines could in future provide 3% of the EU's electricity, reported Andrew Rettman (EU-OBSERVER) from Hammerfest, Norway on 01.06.2006.

The twin turbines submerged under a floating anchored steel supporting structure - 40 metres long by 15 metres wide on the sea surface - are to work by using tidal water movements to provide 3 to 5 GWh of electricity per year.

The picture shows an artist drawing, not a working model - normal marine turbine blades are broader than depicted here. The two turbines are 0.5 MW each, with rotor diameter of 22 metre. The anchor system to the sea bed allows the 270 tonne structure to rise and fall with the tide. The height above water level is given as 7.2m and minimum depth of the rotors as 2m.

The smaller pioneering Norwegian company, Hammerfest Strom, operates a 300kW tidal turbine fixed to the sea bed in the Kvalsundet fjord, which has been powering over 20 homes in the town of Hammerfest since 2003. Their turbine has blades that rotate through 180 degrees during slack inter-tidal water, and so operates efficiently in both tidal directions. See www.e-tidevannsenergi.com/index.htm

Statkraft estimates the tidal stream technology could one day supply up to 100 TWh of power for the EU, with Germany, the UK and the Netherlands already expressing interest in the project.

"They are commercially competitive with wind power," the firm's senior advisor Bjornar Olsen told press in Tromso on 31 May. "But unlike wind, tidal movements are constant. The waters only stay still for two to four hours each day."

Statkraft's first prototype tide farm is set to start work in Tromso's Kvalsundet fjord later this year, with commercial production planned four to six years down the line, Mr Olsen added. See Statkraft's website (in Norwegian)