Projected future European power sector water usage across power scenarios and corresponding trends in water...

The current transition toward added renewables into the power mix is essential to mitigate climate change effects, but the energy transition has environmental impacts outside the scope of greenhouse gas emissions that also need attention. One such impact is the water-energy dependency nexus, where water dependencies are also seen for non-fossil technologies such as concentrated solar power (CSP), bioenergy and hydropower and mitigation technologies such as carbon capture and storage (CCS). In this light, the selection of power production technologies can potentially affect long-term water resource renewability and dry summer conditions, causing, e.g., power plant shutdowns. In this study, we employ an established and validated scheme of water consumption and withdrawal rates across energy conversion technologies at the European scale to project corresponding water usage rates towards 2050 for EU30 countries. We further use the entire range of global- and regional climate model ensembles for low-, medium- and high-emission scenarios to project trends and robustness estimates of freshwater resources and availability at the distributed level for corresponding countries and years towards 2100. The results show a high sensitivity of water usage rates to the implementation of energy technologies such as CSP and CCS, as well as the decommissioning rates of fossil technologies and some scenarios generally show unaltered or even vastly increasing water consumption and withdrawal rates. Further, the assumptions on using CCS technologies, an evolving field, show a high impact. The assessment of hydro-climatic projections showed some degree of overlaps between decreasing water availabilities and increasing power sector water usage, especially for one power production scenario with a high share of CCS implementation. Further, a vast climate model spread in water availability was seen for both yearly means and summer minima, emphasising the need to include extremes in water management, and the water availability was highly dependent on the emission scenario in some regions.