Human activities are dynamically linked to natural resources, including water. When forty percent of the global population suffer from water scarcity, the need for water resource management, therefore, is strikingly evident. An example of such a linkage includes the water-energy nexus (WEN), where natural resources are used to feed the energy grid either directly (e.g. fossils to electricity) or indirectly (e.g. cooling water in thermal plants). Likewise, energy production or conversion depletes stocks of natural resources, impacts ecosystems and emits GHGs. Despite these obvious dependencies, existing and freely available data generally relate to separate categories such as hydrology, climate or energy. Very little data address cross-topic interrelations within the WEN, providing detailed information on spatiotemporal water flows, source/sink etc. as a function of energy source, power plant etc. As a result, estimates of water usages per unit of electricity or fuel produced are often required to analyse the water-energy nexus. In a recent study by (Larsen and Drews 2019) such an approach was successfully used to reconstruct annual observed water usage by energy systems at a country level for Europe.
In the present study, the methodology of (Larsen and Drews 2019) is used in conjunction with projections of future energy pathways developed in the REEEM project (H2020) to depict the future water usage consumed by electricity generation. Despite a tendency towards an increasing share of renewable energy sources using negligible amounts of water compared to thermal plants, a transition phase is currently ongoing. During this transition, large shares of the European energy grid will still depend on extensive amounts of cooling water. Due to climate change, water availability will substantially decrease in certain regions of in particular Southern Europe (Jacob et al. 2014; Matte et al. 2018). On this background, we confront projected future electricity production water usages with current state-of-the-art projections of future water availability as inferred from the CORDEX regional climate model ensemble (Giorgi and Gutowski 2015).