La Rance Barrage is the world's first tidal power station. The facility is located on the estuary of the Rance River, in Brittany, France. Opened on the 26th November 1966, it is currently operated by Électricité de France (EDF), and is the largest tidal power station in the world, in terms of installed capacity. With a peak rating of 240 Megawatts, generated by its 24 turbines, it has an annual output of approximately 600 GWh.
The development costs were high but these have now been recovered and electricity production costs are lower than that of nuclear power generation (1.8c per kWh, versus 2.5c per kWh for nuclear).
The environment has remained healthy but there have been changes. The barrage has caused limited silting of the Rance ecosystem but this has been manageable. Sand-eels and plaice have reduced in numbers but sea bass and cuttlefish have returned to the river. The tides still flow in the estuary and the operators EDF adjusts their level to minimize the biological impact.
The La Rance tidal plant produces a source of energy that is clean, renewable and sustainable. It has no impact on climate because it does not omit any greenhouse gases. The pattern of the tides is preserved so that the impact on species living in the estuary is minimal. The operator, EDF, monitors the tides and weather forecasts to program the barrage operations on a weekly basis.
Since the construction of the barrage a new ecological equilibrium has been established in the Rance estuary and there is an abundance of fish, bird and other wild life. The mean water level in the lagoon is higher than it was before the construction which promoted an increase in boating and sailing activities.
The facility attracts approximately 70,000 visitors per year and a canal lock in the west end of the dam permits the passage of 20,000 vessels each year between the English Channel and the Rance. The highway on the barrage linking Dinard and La Rance is used by 26,000 vehicles each day.