Switzerland is often referred to as the water tower of Europe and with good reason if we compare its energy mix to that of its European neighbours. Hydropower represents almost 60% of electricity produced in Switzerland compared to 12.5% in France, 3.9% in Germany and 17.8% in Italy. The only European countries that feature a higher level of hydropower in their energy mix are Norway (95%) and Austria (60.1%) [2018 figures]. Thanks to hydropower, Switzerland is also one of the countries in Europe with the highest share of electricity from renewable energies.

Swiss hydropower is set to play a central role in the 2050 energy strategy. The Federal Council intends to exploit its potential even further.

With its 2050 energy strategy, the Swiss Confederation plans to increase the annual production of hydroelectricity to reach 38.6 TWh by 2050 (37.4 TWh of which is set to be achieved by 2035). An increase in hydropower generation of 3.2 TWh corresponds to approximately 10% of the current production. As part of this strategy, existing power plants will have to be renovated and extended and the construction of new power plants will be required, all while taking into account environmental requirements. The Swiss Confederation also supports hydropower in a variety of other ways, particularly by contributing to investments in the construction or development of existing facilities, as well as time-limited financial aid for hydropower installations which sell their production on the free market (market premium). However, further measures are still needed to improve the framework conditions for hydropower sustainably and over the long term. Energy law is also being revised.

The vast majority of hydropower facilities depend on glacial intakes, this particularly includes storage structures in the Alps (directly) and some run-of-river power plants located in flood plains (indirectly). Climate change is changing the level of glaciation in the watersheds and therefore glacial contribution to natural inputs.

At present, melting glaciers provide a certain level of regularity in flow rates but only add around 3 to 4% to national production. The disappearance of the glaciers will therefore only have a limited effect on production, even if volumes of incoming water increase by 2040-2050 over the medium term, which means more production for the most frozen catchments. On the other hand, the stability of the water supply in the dams which today is punctuated by melting glaciers will disappear. If relying solely on precipitation in the form of rain or snow, some years will be drier and some wetter than others. Due to this greater variability, reservoirs may not be filled in some years, while there will be too much water in other years.

In terms of short- and medium-term risks, landslides, ground instability, mudslides or floods may occur. But this goes to emphasise the important role of reservoirs in protecting populations downstream from such dangers.

Opportunities also exist as over the long term: future glacial lakes will form in bedrock cover areas and provide new hydropower potential.

In terms of production costs, hydropower costs around 5 to 7 centimes per kWh in Switzerland. However, the costs of photovoltaic and wind power are constantly falling. This may make hydropower seem less competitive.

However, a kilowatt hour of hydropower does not correspond to a kilowatt hour of wind or photovoltaic energy. These energies are intermittent and only produce when the wind is blowing or the sun is shining. Hydropower, by contrast, is much more stable and predictable. Using dams, we can generate precisely as much energy as needed at any given time. This availability and flexibility are the great advantages of hydropower. It is therefore not only necessary to consider the cost price of this energy, but also the value it brings to the energy system.

Pumped storage thus complements new renewable energies in the best way possible. In the event of strong wind turbine and/or photovoltaic generation, this power can be used to store surplus energy by pumping water and then releasing it when needed.