In Switzerland, except of Lake Walen and Lake Constance, all large lakes are regulated by a weir. The weir regulation defines a specific outflow for each individual day of the year for corresponding water levels. Thus, different water uses are taken into account and the protection claims are regulated. Using the climate change scenarios CH2018 and various models, we generate projections up to the end of the century to estimate possible changes in Swiss lakes.
In Switzerland, around 57 % of electricity is generated by hydropower (HP), whereof around 25 % are produced by run-of-river (RoR) power plants. This share is expected to only slightly increase in the context of the Swiss energy strategy 2050, by about 10 % (in total 38’600 GWh/a). Nevertheless, growing energy demand coupled to growing ecological awareness is catapulting hydropower into a position of great expectation and responsibility. In this context, the present research project proposes to assess the impact of climate change and of evolving environmental flow constraints on RoR production in Switzerland. The obtained results are compared to the production increase that could potentially be achieved by technical optimization.