Abstract
Hydropower is a key renewable energy source that provides both base load and flexibility to balance variable solar and wind power. This study presents two planned cases that combine energy flexibility with ecological restoration through pumping solutions. The first case, part of the EU project ReHydro, involves pumping water from a downstream reservoir to a bypassed river section to restore flow and improve trout spawning habitat. The second case explores pumping water from the River Driva to an existing reservoir, with potential for pump-turbine installation to enhance grid balancing. Preliminary results indicate ecological benefits, such as improved salmon habitat and reduced impacts on spawning areas, alongside increased energy flexibility. Future work will focus on optimizing operations under changing climate conditions and assessing biodiversity, thermal impacts, and ice cover dynamics.