Tidal power

The principal tidal power sites around the world are summarised, showing that the UK is fortunate in having three major potential sites. The first use of tidal power for generating electricity was a small scheme near Bristol built 56 years ago. Since then, the 240 MW Rance barrage and the recent 20 MW pilot `Straflo¿¿ turbine installed at Annapolis Royal in the Bay of Fundy are the main schemes built to date. These were built `in the dry¿¿. For an inlet off the White Sea, North Russia, a small tidal power plant was prefabricated complete and towed into position in the early 1960s. This method is favoured for the Severn barrage. An alternative method of in-situ construction has been proposed recently for the River Mersey estuary. Alternative methods of operation are discussed and the economics of tidal power compared with thermal stations. These show that, in the UK, forecasts of coal prices have dominated this aspect. Overall, the tides could be a highly predictable and substantial source of renewable energy whose development involves proven technology.