Thanks to its topography and high levels of annual rainfall, Switzerland has ideal conditions for the use of hydropower. Towards the end of the nineteenth century, hydropower underwent an initial period of expansion, and between 1945 and 1970 it experienced a genuine boom during which numerous new power plants were opened in the lowlands, together with large-scale storage plants.
Based on the estimated mean production level, hydropower still accounted for almost 90 % of domestic electricity production at the beginning of the 1970s, but this figure fell to around 60 % by 1985 following the commissioning of Switzerland's nuclear power plants, and is now around 57 %. Hydropower therefore remains Switzerland's most important domestic source of renewable energy.
