GRAND MAISON is a 1,713 MW hydro power station in Rhone-Alpes, France. It is operated by EDF Energy Ltd [100%]. Based on reported annual generation of 2,085 GWh, it can supply roughly 596k homes. It ranks #22 of 2,216 France power plants by installed capacity. Commissioned in 1987, it is around 39 years old — long-established. As a non-combustion source, it has no direct CO₂ emissions from generation. In context, hydro supplies about 10.4% of France's electricity; the national grid averages 41 gCO₂/kWh (94.9% low-carbon) (2025).
Plant data: WRI Global Power Plant Database (CC BY 4.0), id WRI1002734.
Known, modelled and calculated values are kept separate. Missing fields are shown as unavailable.
The capacity and/or fuel fields on this page include a source-backed provenance label from GEM, an official registry, Wikidata, OSM, or a cross-source match.
capacity: GEM tracker 2026 operating-unit sum (location L100000601642); fuel: WRI source-record fuel
At 1,713 MW, GRAND MAISON is well above the median hydro plant in France (5 MW). Technically it is described as pumped storage. Hydropower converts the energy of falling or flowing water into electricity; output depends on rainfall and reservoir level, and large dams also provide grid balancing and storage.
Capacity comparison computed from the WRI Global Power Plant Database; fuel-type context is general engineering background.
Annual generation (GWh), WRI Global Power Plant Database (CC BY 4.0).
Operated by EDF Energy Ltd [100%].
This hydro plant converts the energy of falling or flowing water through hydro turbines. It sits in a subpolar oceanic climate (Köppen Cfc) — Northern Hemisphere, latitude 45.1°N — which shapes how much energy it can produce and how its output varies through the year.
Monthly mean temperature
Heating degree-days here run 97% above the median power plant in this dataset — a proxy for how much extra energy heated equipment must replace through its surfaces in winter.
Climate heat-demand index: 93/100 — this site sits in the top third of the power plants we cover by heating degree-days.
Climate normals: WorldClim 2.1 (1970–2000 monthly normals, 10 arc-min, CC BY 4.0); zone: Köppen-Geiger world climate classification (Kottek et al. 2006, 0.5° grid). Degree-days & heat-demand index computed by PowerAtlas — a modelled heat-demand proxy, not a measured site figure.
For a plant’s outdoor hardware — heat-recovery steam generators (HRSG), expansion joints, valves, flanges and their insulation — the local climate sets how fast unprotected steel and coatings degrade. This site sits in a mild atmospheric environment (estimated ISO 9223 class C2 — Low), with humidity / wetness the leading environmental stress.
Higher environmental severity is exactly where protective removable insulation pays back most: a sheltered micro-climate slows corrosion, UV and thermal-cycling damage and extends outdoor hardware service life. This is an indicative site-climate context — not a condition assessment of any specific plant or operator.
Indicative estimate via the ISO 9223:2012 informative method (atmospheric corrosivity from temperature, time-of-wetness and airborne salinity), using WorldClim climate normals, the Köppen-Geiger class and coast distance. Indicative, not a measured corrosion rate.
The #1 largest hydro power plant of 428 in France by capacity.
France has 428 hydro power plants in this dataset, together about 19,602 MW of capacity.
Coordinates 45.146, 6.051 from WRI Global Power Plant Database (CC BY 4.0). View on OpenStreetMap.
GRAND MAISON is a 1,713 MW source-record hydro power plant in Rhone-Alpes, France, commissioned in 1987.
GRAND MAISON generates about 2,085 GWh of electricity per year.
Its output is enough to supply roughly 595,800 homes.
GRAND MAISON is operated by EDF Energy Ltd [100%].
