Rance Tidal Power Station
| Company type | Power station |
|---|---|
| Industry | Renewable energy |
| Founded | 1966 |
| Headquarters | Brittany , France |
| Products | Electricity generation (tidal power) |
The Rance Tidal Power Station is a tidal power installation situated on the estuary of the Rance River in Brittany, France.
Commissioned in 1966 as the pioneering tidal power facility worldwide, this 240-megawatt (MW) plant held the title of the largest tidal power station by capacity for 45 years until South Korea's 254-MW Sihwa Lake Tidal Power Station overtook it in 2011.
Characteristics
Equipped with 24 turbines, the station delivers a combined peak capacity of 240 MW and generates roughly 500 GWh annually (506 GWh recorded in 2023). Its mean output is approximately 57 MW, corresponding to a capacity factor close to 24%.
The turbines are "bulb" Kaplan turbine models, each rated at 10 MW, with a diameter of 5.35 m and four blades. They operate at a nominal speed of 93.75 rpm, reaching up to 240 rpm at maximum. Half of these turbines are constructed from martensitic stainless steel, while the remainder use aluminium bronze. To combat corrosion, the facility employs cathodic protection techniques.
Providing about 0.12% of France’s electricity demand, the plant exhibits a power density near 2.6 kW/m2. The cost of electricity production is estimated at 0.12€/kWh.
The barrage extends , linking Brebis point to Briantais point. The power generation section measures in length, and the tidal basin encompasses .
History
An earlier attempt to harness tidal energy took place at Aber Wrac'h in 1925 but was discontinued by 1930 due to financial constraints. This initial endeavor influenced subsequent developments. The utilization of tidal energy has historical roots in traditional tidal mills, notably along the Rance.
The idea for a tidal power station on the Rance was first proposed by Gerard Boisnoer in 1921, inspired by the site's significant tidal amplitude—averaging and peaking at during perigean spring tides. Preliminary investigations were conducted by the Society for the Study of Utilization of the Tides in 1943, though actual construction did not commence until 1961.
Engineer Albert Caquot was instrumental in designing a protective enclosure to shield the site from tidal currents. The construction process involved draining the area over two years through two dams. After completely sealing off the Rance, building work began on 20 July 1963.
The facility was finalized in 1966 and officially opened by President Charles de Gaulle on 26 November. The road crossing became accessible on 1 July 1967, with grid integration following on 4 December that year. Total investment reached ₣620 million (approximately €94.5 million), with a payback timeframe nearing twenty years.
Assessments
Although initial capital expenditure was substantial, the project has since recouped its costs; current electricity generation expenses are lower than those of nuclear power (1.8 ¢/kWh compared to nuclear’s 2.5 ¢/kWh). Nonetheless, its capacity factor remains at about 28%, considerably less than nuclear’s typical range of 85–90%.
Environmental impact
The barrage has induced sediment accumulation within the Rance ecosystem, resulting in the local extinction of species like sand-eels and plaice, while populations of sea bass and cuttlefish have re-emerged. EDF regulates tidal levels carefully to reduce ecological disturbances.
Tourist attraction
The dam features a visitor center that attracted approximately 40,000 guests in 2011. A navigation lock allows vessels up to 1,600 tonnes to transit between the English Channel and the Rance River. Departmental road 168 traverses the dam, connecting Dinard with Saint-Malo, and includes a drawbridge over the lock to accommodate larger ships. The Rance estuary forms part of an inland waterway linking the English Channel to the Bay of Biscay through the Canal d'Ille-et-Rance and river Vilaine.
See also
- List of tidal power facilities
- List of the world's largest power plants
- Renewable energy developments in France
External links
- La Houille Blanche, Issue 2-3, April 1973
- La Houille Blanche, Issue 3, April 1997
- EDF official site