Marine Current Turbines (MCT) has moved a step closer to the commercialisation of its tidal stream technology by completing the installation of a 1.2 MW demonstration device in Northern Ireland.

The SeaGen tidal energy system will be the world’s largest grid-connected tidal stream generator and will provide MCT with valuable experience for its planned commercial-scale tidal projects.

MCT has installed the SeaGen unit in Strangford Narrows where it will undergo a 12-week commissioning and testing phase before its starts supplying electricity to Northern Ireland’s grid.

Martin Wright, Managing Director of Marine Current Turbines said: “This has been a ground-breaking operation, the like of which has never been attempted before and it has attracted interest from around the world.

“MCT’s engineering team is to be congratulated for the excellent progress it has made over the past few weeks in very challenging conditions and we now move to the commissioning phase and commercial operation.”

SeaGen is four times larger than any other tidal stream project completed so far, including MCT’s 300 kW SeaFlow system installed off Lynmouth in southwest England in 2003. When commissioning is complete, it will operate for up to 20 hours per day, supplying power to ESB Independent Energy.

SeaGen consists of two submerged ‘windmills’ with 16 m-diameter rotors, which are driven by the flowing tidal waters. The device can be installed in areas with high tidal current velocities or where there are fast, continuous ocean currents.

The turbines have a patented feature that allows the rotor blades to turn 180° so that they can operate on both the ebb and flow tides. They are mounted on wing-like extensions either side of a tubular steel monopile and the complete wing with its power units can be raised above sea level to permit safe and reliable maintenance.

The 1000 tonne SeaGen structure was initially positioned on the seabed in early April and it has taken six weeks for MCT’s engineers to secure it to the seabed and connect it to a substation on the southern shore of Strangford Lough.

MCT recently signed an agreement with npower renewables, a subsidiary of Germany’s RWE, to develop a 10.5 MW tidal project off the coast of North Wales. It is hoping to commission this project in 2011 or 2012.