Impacts of climate change on river runoff, glaciers and hydropower in the Nordic area. Joint final report from the CE Hydrological Models and Snow and Ice Groups, CE-6.

The two most important questions asked by the hydropower industry as concerns global warming are its effect on future production and on dam safety. These are aspects, which have been studied by the two groups on hydrological modelling and snow and ice within the CE project. The report summarizes the findings and concludes that global warming will increase hydropower production in most areas. It will further shorten the Nordic winter, make it less stable and lengthen the ablation season on glaciers and ice caps. This leads to more river flow the year around. The projected changes may have practical implications for the design and operation of many hydroelectric power plants, and also for other use of water, especially from glaciated highland areas.

The new annual rhythm in runoff will put more stress on spillways. They will probably have to be operated more often, as the unstable winter climate will generate more frequent sudden inflows when reservoirs may be full. This will also have an impact on the infrastructure with more frequent flooding problems downstream of the reservoirs.