Potential for future hydropower plants (HPPs) in Switzerland

Climate change leads to glacier retreat in the Swiss Alps. This has a twofold impact on hydropower in the periglacial environment: new potential locations for HPP reservoirs become ice-free, and additional meltwater from glaciers may be available for production. The Swiss Energy Strategy 2050 anticipates 37’400 GWh of annual electricity production from hydropower in 2035. In 2016, the annual production reached 36’264 GWh. Therefore, a further annual net potential of about 1’136 GWh needs to be exploited.

Glacier runoff projections for different climate change scenarios and global circulation models were applied to 1’576 Swiss glaciers. Currently ice-free sites with high runoff volumes were investigated further. Based on a rating matrix, promising sites were identified. Production, installed capacity, storage capacity, investment costs, and sediment continuity were the most important factors. The leading seven future HPPs have enough technical potential to achieve the interim 2035 goal of Energy Strategy 2050 concerning electricity supply, together with the HPPs to be commissioned soon (i.e. Gletsch-Oberwald with 41 GWh annual production). Table 1 shows estimates for annual production, installed capacity, reservoir volume, and storage energy equivalent of the new plants. The latter is of particular interest as a measure for winter production which will gain in importance with the increase of new renewables for electricity production. Narrow gorges and steep rocky slopes provide favourable technical conditions, although natural hazards will have to be accounted for carefully. Nevertheless, construction site preparation will be costly, there will likely be societal controversy as some sites are located in protected areas, and the integration into the existing dense hydropower network will be a major challenge.