Electricity sector in Switzerland
The electricity sector in Switzerland relies mainly on hydroelectricity, since the Alps cover almost two-thirds of the country's land mass, providing many large mountain lakes and artificial reservoirs suitable for hydropower. In addition, the water masses drained from the Swiss Alps are intensively used by run-of-the-river hydroelectricity (ROR).
Source: Wikipedia — Electricity sector in Switzerland (CC BY-SA 4.0)