Five training schools, research exchanges and new publications support the next generation of hydropower professionals and the sector's clean energy transition
Brussels — PEN@Hydropower, the Pan-European Network for Sustainable Hydropower (COST Action CA21104), has concluded its four-year programme of European cooperation. The Action brought together researchers, industry, policymakers and civil society to address hydropower's changing role in the energy system, combining scientific exchange with practical training and guidance for a more sustainable sector.
Through five Working Groups, PEN@Hydropower connected expertise in energy flexibility and storage, technological innovation, environmental sustainability, climate adaptation, policy and stakeholder engagement. From its September 2022 kick-off in Brussels to its final activities in September 2026, the programme combined meetings across Europe with regular online collaboration, research mobility and conference participation.
A major outcome is the open-access book Rethinking Hydropower: A Holistic Vision for a Sustainable Future, published by Springer in September 2026. Edited by Eduard Doujak, Sebastian Muntean, Daniel Patauner and Elena Vagnoni, it brings together the network's research and educational experience. It provides a lasting reference on sustainable hydropower assessment, professional training, technology and policy.
The Action also published Digitalisation in Hydropower, a whitepaper developed by Working Group 2. It sets out a European agenda for modernising existing plants through secure data systems, artificial intelligence, predictive maintenance and digital twins. Its recommendations link digital investment to plant refurbishment and call for common data foundations, demonstrations, skills development and appropriate recognition of hydropower's flexibility services.
Capacity building was a central achievement. Five Training Schools on Sustainable Hydropower, held in Timișoara, Thessaloniki, Porto, Uppsala and Salzburg, attracted more than 110 participants. The schools combined lectures, stakeholder exercises and visits to operating plants, helping participants apply the Hydropower Sustainability Standard and assess projects from environmental, social, governance and technical perspectives. The programme connected young researchers with experienced professionals and hydropower operators.
Short-Term Scientific Missions, virtual mobility and conference grants supported collaboration across institutions and countries. The resulting scientific mission reports cover subjects including hydropower flexibility and machine lifetime, barriers to digitalisation, greenhouse gas emissions, climate impacts and social acceptance. These exchanges gave researchers access to expertise and host institutions while contributing to the Working Groups' joint outputs.
The Women's Mentoring Programme ran in two cohorts, with six mentor–mentee pairs in 2024–2025 and seven in 2025–2026. Mentor training and career development activities supported women's professional growth and connections across the sector. Young Researchers and Innovators also accounted for more than half of the membership in each of the five Working Groups, placing the next generation at the centre of the network.
Stakeholder events linked research with practical and policy questions. Discussions in Naples addressed system integration, digitalisation, social acceptance and regulatory priorities. The Knowledge Symposium on Hydropower Research Gaps, co-hosted with EERA JP Hydropower, examined flexibility, biodiversity, climate change and infrastructure resilience. The Rethinking Hydropower Dialogue in Brussels on 7 September 2026 marked the culmination of four years of exchange between the research, industry and policy communities.
The Action's publications, research reports and training materials are available through its Results and Knowledge Base, providing resources for educators, researchers, operators and public authorities to use in future work on sustainable hydropower.
Notes to editors
PEN@Hydropower (COST Action CA21104) ran from 14 September 2022 to 13 September 2026. Chaired by Dr Eduard Doujak of TU Wien, it was the first COST Action focused on hydropower technology and sustainability. The Action was supported by COST, European Cooperation in Science and Technology.
Further information: www.pen-hydropower.eu