La Rance tidal power plant was inaugurated in 1966, after 5 years of construction.It was the world’s firts tidal plant and has been the largest tidal power station in the world for 45 years.



The Rance Dam has the following characteristics:

  • length of 750 meters
  • tidal basin of 23 square kilometers. The barrage of the plant makes it possible to constitute a pool of water. This water supply is then released twice a day into the 24 turbines.
  • Exploitation of incoming and outgoing water flows
  • power of 240 MW, generated by the 24 reversible and bulbous Kaplan-type turbines, of 10 MW
  • average annual electricity production of 550 GWh (ebb tide) plus 60 GWh (rising tide)
  • charge rate: about 26% (2,500 hours)



The Rance tidal power plant produces an average of 550 GWh/year of marine electricity. This production corresponded to 2.4% of the electricity consumption in Brittany in 2010.

An agreement between EDF and Guernsey Electricity, Guernsey Electricity’s sole commercial electricity supplier, has been concuded to power the island with power generated by the plant via a 60 MW  submarine cable. This  energy covered a third of the annual electricity needs of the island of Guernsey.


Few tidal power plants in the world

For 45 years, the Rance tidal power plant remained the largest tidal power plant in the world. Today, there are only four significant tidal power plants :

  • Shiwa in South Korea (254 MW)
  • The Rance in France (240 MW)
  • Annapolis in Canada (20 MW)
  • A 5 MW installation in China plus a few more modest installations

Nevertheless, other projects are under study or under construction, notably in South Korea and in the United Kingdom.


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