The hydropower sector is sensitive to climate variables as these directly affect energy generation and consumption. Reservoir-based hydropower can better cope with climate variability in space and time and offers possibilities to regulate production. Climate services provide key information to optimize reservoir operations and to manage water storage in a changing climate, such as projections of future precipitation, temperature and river flow. With many climate services flourishing across Europe, the challenge today is to develop energy indicators based on these climate services which can facilitate decision-making at the regional and local levels, most particularly in a context of climate change adaptation and building resilience. In this study, we investigate the impacts of projected evolutions of river flows on the operation of reservoirs. The study is based on GCM/RCM (RCP 4.5 & 8.5) climate model projections for two future periods: near future (2021-2050) and mid-century period (2061-2090). Both are compared to a reference period (1976-2005). Five GCM/RCM projections from the SWICCA project (Service for Water Indicators in Climate Change Adaptation, http://swicca.eu/) are used. The SWICCA service is run by the Swedish Meteorological and Hydrological Institute (SMHI) and contributes to the Copernicus Climate Change Service (C3S). From SWICCA, we extracted the flows at several river locations in France. The simulated and projected flows were then used to evaluate operation guide curves for reservoir management. These curves translate the rules to achieve management goals for reservoir levels throughout a year. In our study, we considered multipurpose reservoirs, with the rule curves representing the compromise between a target objective of minimum reservoir level during the summer season, a minimum daily release flow and hydropower production. Based on the trajectories of the rule curves obtained, differences between current and future operating rules of hydroelectric installations in the context of climate change adaptation are evaluated. Results highlight the conditions under which water volumes are available (or not) to optimize hydropower production. We also discuss the possibility of applying the methodology to create a new indicator to characterize the flexibility of water-energy systems in future climate.
Acknowledgements: This work was funded by the project AQUACLEW, which is part of ERA4CS, an ERA-NET initiated by JPI Climate, and funded by FORMAS (SE), DLR (DE), BMWFW (AT), IFD (DK), MINECO (ES), ANR (FR) with co-funding by the European Commission [Grant 690462].