What are the consequences of melting glaciers on our hydroelectric potential?

Initially, melting glaciers are expected to increase our hydroelectric potential. In the medium term, this potential should begin to decline. The consequences beyond 2050 remain uncertain.

The water turbined by our hydroelectric plants comes, in part, from annual precipitation (rain, snow). The balance results from the melting of glaciers. For the past three decades, the volume of water produced by melting glaciers has been increasing due to global warming. With the accelerated retreat of glaciers, these flows could continue to increase in the coming decades, thus increasing our potential for hydroelectric production, provided that we have the necessary facilities to turbine these additional volumes of water. It will therefore be necessary to strengthen the capacity of the storage dams to manage all this water [→ Q76]. The day will come, probably between 2030 and 2050, when glaciers have receded so much that melt-water volumes will begin to decline, reducing river flows and potential storage relative to today. At the current rate, Swiss glaciers will have virtually disappeared by the end of the century. This could reduce Switzerland’s hydropower output once the glacier meltwater input has been exhausted.

In the absence of water from melting glaciers, dams will have available impoundment volumes that could be reallocated to pumped storage, potentially to provide seasonal storage capacity [→ Q75]. In addition, glacial lakes could form in place of melting glaciers. This could result in new opportunities for dam construction and hydroelectric generation. These structures may also play the role of regulating flows in downstream rivers during hot and dry periods.

Climate change could have yet another impact on our hydroelectric generation. Climatologists predict an increase in annual precipitation in winter as well as on the northern slopes of the Alps and a decrease in summer and on the southern slopes. At this stage, it is difficult to assess the consequences that this could have on our hydropower production.