Variations in Discharge Volumes for Hydropower Generation in Switzerland

This study analyses the way climatic variations over the last century impacted the volumes of water available for hydropower production in Switzerland. The analysis relied on virtual intakes located all over Switzerland, which were assumed to be fed by water from mesoscale catchments. Intake capacities were designed using flow duration curves. The results show that the overall warming and increased winter precipitation observed in recent decades have led to more balanced discharge behaviours in rivers and more favourable conditions for electricity production than most periods in the past. In lower-altitude regions of Switzerland, the annual volume of water available for electricity production has not changed significantly; however, significantly more water is available in winters, while less is available during summers. In higher-altitude regions like the Swiss Alps, especially in glaciated catchment areas, significantly more water is available in both seasons; in other words, the annual volume of water available for hydropower production is significantly higher in these areas when compared to earlier periods. Comparison of these results with the actual amount of hydroelectricity produced over the same period reveals that hydrological variations cannot fully explain the variations in power production observed. Plant-specific analyses are needed of the impact of climatic changes on water management.