Big is beautiful: why marine current turbines need to be scaled up

Marine current turbine development seems to have slowed down in recent years. Only a few prototypes are being tried and tested, all sized at around 1 MW, (SeaGen being the only exception, slightly exceeding this size). As yet there is not a single array of in-stream turbines operating commercially, although some are planned. The existing technology appears to be too expensive to be able to generate at a commercially competitive cost compared, for example, with offshore wind turbines, which have to be the baseline for comparison. It seems likely that this is inhibiting investment in new, otherwise promising tidal technology.