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.

Hydropower and storage capacity need to increase to meet the need for renewable and dispatchable power generation. According to IEA, worldwide hydro-power capacity should increase from 1,360 GW in 2021 to 1,563–1,782 GW by 2030 and up to over 2,500 GW in 2050. At the same time, hydropower refurbishment projects must implement modern sustainability standards that preserve biodiversity and contribute to climate change mitigation and adaptation. The main objective of ReHydro is to demonstrate how European hydropower can be refurbished and modernized to be fit for a leading role in the future power system respecting sustainability requirements and societal needs in a climate change context. A suite of monitoring and digital tools (performance, cavitation, machine health) implemented at demonstration sites will improve hydropower efficiency. Innovative concepts like retrofitting with pumped hydro and hybridization will make hydropower fit for future markets. ReHydro will demonstrate how biodiversity can be improved with new fish-friendly turbines, re-establishment of environmental flows, and monitored using new tools such as eDNA. Smarter use of water resources will also be implemented so that more services can be delivered to the power markets, while multi-purpose use of the water resources for navigation and recreation can be expanded and the ability to mitigate flooding and droughts is strengthened. The results from ReHydro will achieve all the expected outcomes specified in the call. The solutions will give European hydropower industries commercial advantages to utilise the global need for hydropower expansion. It is expected that ReHydro's exploitable results will create 700–1150 new jobs in the manufacturing industry, increasing the global market by 275 mill euros. ReHydro will introduce a new paradigm to boost European leadership and competitiveness in the hydropower industry and provide new sustainable solutions that are replicable at European and global levels.

The ultimate objective of the XFLEX project is to increase hydropower potential in terms of plant efficiency, availability and provision of flexibility services to the Electric Power System (EPS). The high Renewable Energy Sources (RES) scenario of the decarbonisation process relies on a drastic change of the European Union EPS with a massive integration of non-dispatchable RES and disconnection of the so-called conventional units, as greenhouse gases emitters. These changes influence drastically the provision of the power grid balancing, and challenge the EPS operations and safety. It is of upmost importance to provide reliable solutions to support the EPS with more flexibility services. Hydroelectric Power Plant (HPP) already significantly supports EPS flexibility in terms of regulation capability, fast frequency control, fast start/stop, fast generating to pumping modes transition, high ramping rate, inertia emulation, fault ride through capacity, etc. XFLEX aims to demonstrate an innovative methodology for system integration of hydroelectric technology solutions, variable speed being a key component and a reference, to provide further enhanced flexibility services assessed by a crosscutting analysis of their impact on both the technology and the market aspects. Innovative solutions also target an optimize maintenance plan to decrease the outage time and increase the availability of the plant. Demonstrations are scheduled in the cases of run-of-river, storage and pumped storage HPPs and they cover cases of refurbished, uprated and especially existing HPP to be applied and scaled to any unit size. XFLEX draws the roadmap for the exploitation of its solutions to all the European HPP fleet. A strategic dissemination plan is set to promote the deployment of the demonstrated solutions to stakeholders, to the scientific community and the public and to further support the communication in workshops, conferences, scientific journals, newspapers and various social media.

FIThydro addresses the decision support in commissioning and operating hydropower plants (HPP) by use of existing and innovative technologies. It concentrates on mitigation measures and strategies to develop cost-efficient environmental solutions and on strategies to avoid individual fish damage and enhancing population developments. Therefore HPPS all over Europe are involved as test sites. The facilities for upstream and downstream migration are evaluated, different bypass systems including their use as habitats and the influence of sediment on habitat. In addition existing tools and devices will be enhanced during the project and will be used in the experimental set-ups in the laboratories and at the test sites for e.g. detection of fish or prediction of behavior. This includes sensor fish, different solutions for migration as e.g. trash rack variations, different fish tracking systems, but also numerical models as habitat and population model or virtual fish swimming path model. Therefore a three-level-based workplan was created with preparatory desk work at the beginning to analyze shortcomings and potential in environment-friendly hydropower. Following the experimental tests will be conducted at the different test sites to demonstrate and evaluate the effects of the different options not covered by the desk-work. Thirdly, these results are fed into a risk based Decision Support System (DSS) which is developed for planning, commissioning and operating of HPPs. It is meant to enable operators to fulfill the requirements of cost-effective production and at the same time meet the environmental obligations and targets under European legislation and achieve a self-sustained fish population.