SeaGen Tidal Turbine Power: How it works

SeaGen is by far the largest and most powerful tidal turbine in the world with twin rotors each sweeping over 200 square metres of flow. Tidal turbines work much like submerged windmills, but driven by flowing water rather than air. They can be installed in the sea at places with high tidal current velocities, or in places with fast enough continuous ocean currents, to take out copious quantities of energy from these huge volumes of flowing water.

It has the capability to deliver about 10MWh per tide, which adds up to 6,000MWh per year. This is approximately the rate of energy capture that a wind turbine of about 2.4MW rated capacity can typically produce. So SeaGen shows that the tides are not only more predictable than wind but twice as productive.

SeaGen is intended for widespread commercial use and future projects can use variants with twin axial flow rotors of 14m to 20m in diameter (the size depending on local site conditions), each driving a generator via a gearbox much like a hydro-electric turbine or a wind turbine. These turbines have a patented feature by which the rotor blades can be pitched through 180o in order to allow them to operate in bi-direction flows -- that is on both the ebb and the flood tides. The twin power units of each system are mounted on wing-like extensions either side of a tubular steel monopile some 3m in diameter and the complete wing with its power units can be raised above sea level to permit safe and reliable maintenance.