Integrating large quantities of intermittent solar and wind energy at an accelerated pace will present a formidable challenge to the power grid. Our energy system will have to become more flexible, and policy-makers will have to ensure that the energy transition does not create disruptions. XFLEX HYDRO, and the demonstration that hydropower can provide additional flexibility is a building block towards this goal.

XFLEX HYDRO is a European Union Horizon 2020 research and innovation project with the objective to show hydropower’s technical and strategic role in demonstrating how renewable-based generation can be achieved in a secure and reliable manner. Thanks to this project, the sector has gained a better understanding of the flexibility that the existing EU hydropower fleet can provide to the electrical system, and demonstrated how, using a set of innovative technologies, this flexibility potential can be optimised and enhanced.

These innovative hydroelectric technological solutions are the following:

• Variable speed units;
• Hydraulic short circuit;
• Hybridisation with a battery energy storage system; and
• Smart Power Plant Supervisor (real-time optimisation methodology)

The project puts hydropower at the forefront of innovation, strengthening the industry’s know-how, improving its technology export potential, and facilitating job creation. This document is designed to speak to a wide range of stakeholders and its content is laid out in a manner so that the relevant information is clear, accessible, and actionable by the reader. The technical part of this report provides the key takeaways from the project and enables plant owners and energy experts to identify opportunities to introduce some of the findings in their plants.

This set of conclusions can be found in Section 4, where the four technologies relevant to the European hydropower fleet are discussed (presented individually, as well as in six possible upgrade strategies). To facilitate the identification of the relevant combination of technologies, these upgrade strategies are classified under the three categories of hydropower plants: reservoir storage plants (RSP), pumped storage plants (PSP) and run of river plants (RoR).

Despite the remarkable results achieved by the project and the technical benefits associated with the deployment of these innovative technologies, several barriers are currently limiting their wider adoption in the European context. The flexibility provision of the hydropower fleet will only be entirely optimised and utilised if dedicated energy policies are put in place, aimed at securing the availability of indigenous flexibility solutions over the next decades.

Through the dialogue carried out within the consortium’s partners and external energy experts, seven key recommendations have emerged:

• Recognise and value hydro flexibility as an essential service to the power system to achieve a successful energy transition. As power systems are progressively losing the flexibility provided by non-renewable conventional energy sources, recognising, and valuing the growing necessity for flexibility services is crucial to ensure grid stability and security of supply over the next decades.
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• Remove regulatory barriers for unrestricted implementation and operation of hydro flexibility technologies. To unlock the full potential of existing hydro assets and introduce new technologies, it is essential to eliminate regulatory barriers that limit the adoption of flexibility upgrades or that create discrepancy in the procurement process of flexibility services. For example, in certain countries operating in hydraulic short circuit mode is currently not allowed.
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• Provide remuneration mechanisms enabling investment in flexibility. Existing electricity and ancillary services markets (when available) excel in ensuring that the service required is provided at minimal cost to consumers, but their short-term nature does not provide the long-term revenue visibility required to justify new investment in flexibility technology upgrades.
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• Facilitate cross-border collaboration for efficient exchange of flexibility services. Encouraging international collaboration among European countries is essential for the efficient exchange of hydro flexibility services and expertise. By fostering cross-border connections, countries can share resources and expertise, optimising the utilisation of hydro flexibility on a broader scale.
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• Streamline licensing renewals for optimised hydropower operations. Simplifying the licensing process and accelerating permitting procedures are vital for the operational stability of hydropower projects. This not only reduces uncertainties linked to licence renewals and ownership transfers but also provides a clear and predictable framework in which power companies can operate.
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• Conduct system-level analysis to anticipate and address future flexibility needs. To effectively address future challenges and make sure that electric power systems can deliver a safe energy transition, system-level analyses are essential. These can provide the long-term vision needed to identify and prepare for future flexibility challenges in the most technically efficient, secure, and cost-effective way.
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• Promote support mechanisms for the modernisation of ageing hydropower infrastructure. Financial or tax mechanisms that support the modernisation of ageing infrastructure are essential to secure and enhance the benefits currently provided to society by these plants. These mechanisms should be focused on rewarding modernisation projects that are introducing cutting edge technologies and leading in the adoption of cleaner and more flexible energy solutions.