Beyond the Power Plant – Reconciling Storage Hydropower and Biodiversity in the Energy Transition

Storage hydropower, the dam-based backbone of renewable electricity systems, plays a crucial role in the energy transition by providing flexible capacity, seasonal storage, and grid stability. However, the same operational flexibility that enables climate-friendly energy production also imposes significant pressures on river ecosystems through hydropeaking: rapid, often sub-daily flow fluctuations caused by on-demand hydropower production that alter riverine habitats and threaten biodiversity.                                                                                         

Recent studies show that the ecological impacts of hydropeaking scale non-linearly with its frequency and amplitude, creating cumulative stress on aquatic communities far beyond the disturbance caused by natural flow events such as floods. For instance, with every hydropeak, organisms such as fish and invertebrates risk stranding on rapidly drying riverbanks leading to high mortality and the loss of often highly specialized species.                                                   

As hydropeaking is expected to increase in the near future, driven by the growing need to balance volatile renewable energy from wind and solar in a CO₂-neutral way, reconciling large-scale, climate-friendly electricity flexibility with local, effective biodiversity conservation will become increasingly challenging. The biodiversity–energy dilemma can therefore not be solved at the scale of single hydropower plants and will require strategic, system-level planning that integrates ecological and hydropower-operational perspectives.           

This talk synthesizes recent empirical results and conceptual insights on hydropeaking impacts and calls for the development of criteria-based approaches to guide coordinated hydropower management at the catchment and national scales. Such approaches could enable transparent, evidence-based decisions that balance energy production with biodiversity conservation for a sustainable and environmentally friendly development of our energy system.