Impact of climate change on hydro-energy systems: An overview

Increasing concentrations of the greenhouse gases CO2, CH4 and N2O in the atmosphere, caused by anthropogenic activities, lead to an increase in global surface temperature, which can produce wide-ranging impacts on natural systems, such as the hydrologic cycle. The paper reviews the various consequences of global warming for the Alpine region, namely changing patterns of precipitation (i.e. more in winter and less in summer), reduced total mean annual precipitation, melting of glaciers, and more frequent occurrence of earth surface processes (rock slides, debris flows, larger volumes of transportable materials) in higher altitude catchments, posing serious hazards to storage facilities of hydropower plants (dam, spillway, intakes, communication lines, etc.). Modelling of the discharge from eleven catchments shows a decreasing trend of annual runoff. Compared to the period 1961-1990, hydropower plants are therefore expected to have a reduced energy output in the order of 7% to 11% by 2050, and 20% to 30% by the end of the 21st century.