The SeaGen tidal generator from Marine Current Systems is an operational tidal system based in Strangford Narrows in Northern Ireland. The system consists of twin submerged axial-fl ow rotors – measuring 16 metres in diameter – which are attached to a central machine and control tower that is fi xed to the seabed. Both rotors on the SeaGen sport a unique feature that allows the blades to be pitched through 180 degrees, allowing them to operate in both tidal directions. Appearing like an upside-down submerged windmill, SeaGen works by converting high-velocity currents into usable electricity throughout the tidal cycle – much as a windmill utilises the power of the wind to rotate its sails.
Indeed, its large-scale rotors – aided by the 400 million gallons of water that fl ow past it twice a day – can develop a rated power of 1.2 MW at a current velocity of 2.4m every second. This gives SeaGen the ability to deliver about 10 MW per tide, which annually amounts to 6,000 MWh of energy.