Muttsee

Muttsee is a reservoir in the Canton of Glarus, Switzerland, with a surface area of. It is used as the upper reservoir in the 1 GW pumped-storage hydroelectricity Linth–Limmern Power Stations.
The 2.4 km high altitude permits a 2.2 MW solar farm to supply 3.3 GWh per year, more than average power, even in winter. The 6,000 photovoltaic panels were installed on the containment wall of the artificial basin in 2021, covering approximately 10,000 square meters of concrete, and stretching over almost 1 km.