Grand'Maison Dam, Embankment dam in Vaujany, France
Grand'Maison Dam is a 550 m long, 140 m high embankment dam on the Eau d'Olle at 1,700 m altitude in Vaujany, Isère. Its dark, gravel-covered stone face is crossed by narrow lighter horizontal bands, with a straight crest below a mountain ridge and a grassy field at its base. The dam forms the upper reservoir of a pumped-storage plant.
Construction began in 1978 and ended in 1985, with commissioning in late 1987. The dam was built as the upper reservoir of a pumped-storage plant, using the same design as the Mont Cenis and Serre-Ponçon dams. A machine named Atlas placed 70,000 tonnes of welded steel pipes, and 32 km of departmental roads were widened while 18 km of new roads were built.
The dam is nicknamed the "hydro-nuclear dam" because its pumps run on surplus nuclear power at night, lifting water from Lac du Verney to Grand'Maison. The nearby EDF Hydrélec museum presents the dam and its machinery, and the reservoir is also used for recreation.
The dam stands at 1,700 m altitude on the Eau d'Olle above Vaujany, reached by roads widened and built for the 1978-1985 works. The EDF Hydrélec museum nearby presents the dam and its pumped-storage installation. The crest is 550 m long and the face 140 m high, so allow for mountain weather.
The dam is nicknamed the "hydro-nuclear dam" because its pumps, powered by surplus nuclear electricity at night, lift 135 m3/s from Lac du Verney into Lac de Grand'Maison, using 1,270 MW. The station can switch from pumping to generation within minutes, producing as much power as two nuclear reactors.
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