Assessing the energy potential of modernizing the European hydropower fleet

About 50% of all hydropower plants (HPPs) worldwide were originally commissioned more than 40 years ago, so that the advanced age fleet is a major concern across continents, and especially in Europe. The modernization HPPs can generate several benefits terms generation, flexibility, safety, operation, may have neutral or even positive implications for environment. In this work, we appraise options existing plants, with exclusion measures expected to increase hydro-morphological pressure on water bodies (e.g. withdrawals new parallel waterways): dam heightening, head loss reduction waterways, weighted efficiency electro-mechanical equipment, digitalization inflow forecast, floating photovoltaic (evaporation reduction). We provide an indicative estimation additional power annual generation could be obtained compared current condition. estimate overall energy increased by 8.4% European Union 9.4% whole Europe implementing above-mentioned strategies. gain achievable increasing was discussed but not included above mentioned indicator, because it very site-specific. storage reservoir interconnection coordinated operation has been estimated literature as 169 TWh. This suggests significant energy, should considered important element policy, also considering reliability flexibility system deliver. here, insofar entailing worsening alterations, are cause limited no conflict environmental objectives policies