High-pressure storage power stations in Misox

Misoxer Kraftwerke AG, which is situated in Mesocco (GR), is a plant which is co-owned by Elektrizitäts-Gesellschaft Laufenburg AG (68%), Centralschweizerische Kraftwerke AG (20%), Graubünden cantonal authorities (10%) and various concession authorities (2%). The power station facilities were built between 1957 and 1963.

The Misox power stations use the water from the catchment of the River Moesa in Misox Valley and the River Calancasca in the Calanca Valley. These two valleys are situated to the south of the San Bernardino Pass in Graubünden.

The 45 m high Isola arch-gravity dam stands directly to the south of the village of San Bernardino. It forms the Isola reservoir with a top water level of 1604 m above sea level and has a storage capacity of 5.9m m3.

It is a 2-stage power station system:
The upper stage comprises the Isola and Valbella power stations and the shared Spina underground central power station in Pian San Giacomo. The Isola power station processes the inflow from the higher-level Misox, which has a catchment of 43.5 km2. This inflow is stored in the Isola reservoir. The Valbella power station processes the inflow from the Calanca Valley at the back with a catchment of 42.3 km2 and which is transferred to the Misox.

The lower stage is formed by the Soazza power station with the underground central power station below the village of Soazza. The Soazza power station is fed the works water from the Isola and Valbella power stations, as well as the inflow from the 24.5 km2 intermediate catchment which is also collected and stored in the Corina compensating basin.

The mean annual production is 316m kWh, with 74m kWh generated in the cold half of the year and 242m kWh generated during the warm half of the year.

The managerial mandate is held by Axpo Hydro Energy.