As energy and water are closely linked to each other the tranformation of the energy sector can cause conflicts or synergies between the Sustainable Development Goals (SDGs) for water (SDG 6: Clean Water and Sanitation) and energy (SDG 7: Affordable and Clean Energy). Direct and indirect, remote impacts of renewable and conventional energy systems on global water resources and related usage competitions may increase under the terms of climate change. Intensifying the cultivation of energy plants or expanding hydropower may contradict the aim of global food security or other social and ecological development goals. Recent studies on global availability of water of appropriate quality display a trend towards regional scarcity. In the course of reorientating the supply with energy it has to be examined regionally and globally whether the availability of water or potential impacts on water resources can be limiting factors. When it comes to the realisation of the SGDs 6 and 7 (water and energy) possible conflicting goals or synergies have to be assessed.