Addressing tradeoffs beyond disciplinary borders: HYDROpot_integral as a tool to simultaneously assess hydropower potential and ecological potential

The steadily growing demand for energy and the simultaneous pursuit of decarbonization are increasing interest in the expansion of renewable energies worldwide. Hydropower produces around 60% of Switzerland's electricity and plays a key role in this energy transition strategy. However, habitat and ecosystem protection and climate friendly renewable energy production are sometimes at odds. While the environmental impact is usually addressed at some level, there is a lack of standardization and tools for a global assessment are still scarce. The GIS-based tool HYDROpot_integral allows the consideration of the total hydropower potential as well as the ecological potential of a region. Based on ecological and socio-economic geodata, both the current state of each river reach and the hydropower potential is assigned a rank. To record the suitability, every river reach is ranked according to their ecological, cultural and economic ecosystem services. A low rank means that a river reach is more suitable for hydropower production at low cost in terms of ecological and cultural ecosystem services; a high rank indicates high ecological and cultural ecosystem services and low economic services and is therefore more suitable for protection. As the limit between hydropower use and protection is adjustable, different scenarios can be explored. Results from five mesoscale test catchments in Switzerland show the feasibility of the present method, to provide a comprehensive and meaningful basis that can support the decision-making process. Overall, the assessment method is to be understood as a flexible tool to address tradeoffs between hydropower potential and ecological potential.