Exploring the impacts of climate change on French hydropower generation

Hydropower can play a crucial role in decarbonizing national power mixes, in particular in managing the variability of other renewable energy sources. However, climate change is expected to affect the water resources and could impact hydropower generation. This study explores the potential impacts of climate change on hydropower generation in France and its broader consequences on the national power system.  To achieve this, an innovative modeling approach is used, coupling a land surface model driven by outputs of Euro-CORDEX projections and a power system optimization model. The land surface model represents the management of French hydroelectric reservoirs based on the available water resources and the optimal national power dispatch simulated by the power system model. The system takes into account the national regulations on water management. Our findings indicate that climate change should not have a significant impact on the annual national production of hydroelectric reservoirs, even under extreme scenarios. However, noticeable changes in the seasonality of production due to hydrological changes are found. Production is higher during winter due to higher liquid precipitation, at the expense of spring production due to lower snowmelt. This reduces the need for dispatchable sources in winter and helps to decarbonize the power system. Moreover, we find heterogeneous impacts across regions and the uncertainties in changes in mountain precipitation appear to be a critical factor. Finally, changes in inter-annual variability and drought occurrences and their potential impacts on hydropower are also examined.