Developed by Marine Current Turbines, Sea Gen is the world’s first large scale tidal stream generator. The first of it was installed on Strangford Narrows between Strangford and Portaferry in Northern England in the month of April in 2008 although it was connected to the grid only in the month of July 2008. It is not that it did not have its own problems. During the time t was being commissioned there occurred an software error and this resulted in the production being the half of maximum till the autumn of 2008. Once, MCT fixed the error it was promised that it won’t occur again and since then it has been producing a whopping 1.2 MW or 18-20 hours a day while the tides are forced in and out of Strangford Lough through the Narrows. Not to forget is the fact that it is four times more powerful than the next tidal stream generator in the world.
The weight of Sea Gen being 300 tonnes, the structure consists of twin axial-flow rotors of diameter 16 metres and each of them drives a generator through a gearbox like a hydro-electric or wind turbine. The turbines that we are talking about here have patented feature by which the rotor blades can be pitched through 180 degrees allowing them to operate in both flow directions- on both the ebb and flow tides.
The power units which are mounted on arm-like extensions either side of a tubular steel monopile some 3metres in dia. and the arms with the power units can be raised above the surface for safe and easy maintenance access. For the time being Sea Gen has been licensed for a period of just five years after which a comprehensive environmental monitoring programme would be carried out to determine the precise impact on the marine environment.
The first prototype of tidal stream generator was demonstarted by the manufacturers in 1994 and the system was just of 15 kilowatt at that time. In May 2003 Sea Flow, the prototype for Sea Gen was installed and it was a single rotor turbine which generated 300KW but it was never connected to the grid. It remained the world’s largest offshore tidal generator until Sea Gen dethroned it.