Currently, hydraulic turbines are employed across a broad spectrum of operational regimes. A particular case is represented by the environmental flow (E-flows), which are essential for the conservation of fluvial ecosystems but often force to operate out of design parameters or rather switch off the plants. On the other hand, the impact of HPPs on water quality and biodiversity up- and downstream is enormous and should also be a target for refurbishing actions. In this context, the SHERPA project will develop and validate innovative technologies for refurbishing current HPPs, namely, 1) AM metallic patches and coatings to minimize damage and enhance resistance to cavitation, 2) new strategies to adapt rotational speed depending on the flow range, 3) advanced air injection systems to improve water quality and efficiency; 4) new runner designs adapted to E-flows increasing performance. Modelling, simulation, and monitoring tools will assess the new solutions of the in terms of energy output, flexible operation, cost-effectiveness, and impact on biodiversity. The goal is to expand and/or adapt the operational range of the HPP to include lower flows, without this harming their lifetime, economic viability, and environmental and social impact. In order to meet this objective, the project proposes a methodology comprising 8 work packages groups in four blocks to be carried out during 42 months. SHERPA has a well-balanced consortium with 7 partners from 4 countries, covering all the competences and know-how in terms of expertise, resources and positioning in the field, which will ensure the achievement of the project objectives and make an impact at European level.