Deploying Large-Scale Hydropower in the UK

Large-scale hydropower has an important role to play in building a more resilient, flexible and secure UK energy system. This Strategic Summit session examines how pumped storage hydropower, tidal range and existing hydro assets can support Clean Power 2030 while strengthening the country’s ability to manage long-term risks, balance renewable generation and reduce dependence on fragile supply chains.

The discussion begins by challenging the way energy infrastructure is traditionally valued. Panellists argue that the lowest-cost option is not always the option that delivers the greatest long-term value. In a system increasingly shaped by geopolitical uncertainty, cyber threats, supply chain pressures and rising electricity demand, resilience, strategic redundancy and sovereign capability become just as important as short-term efficiency. Hydropower is presented not simply as a generation technology, but as critical national infrastructure capable of supporting the electricity system for generations.

A major focus of the session is pumped storage hydropower, the UK’s largest established form of long-duration electricity storage. As wind and solar provide a growing share of generation, pumped storage can absorb excess power and release it when demand is higher or renewable output falls. The panel explores the cap-and-floor mechanism designed to reduce investment risk and unlock new projects, while also considering the economic, strategic and financial criteria used to determine which schemes should receive support.

The discussion also highlights the scale and longevity of proposed projects. Developers outline how new schemes are being designed to provide extended storage durations, major grid support and infrastructure lifetimes of 80 to 100 years or more. Detailed site selection, access to the transmission network, ground conditions, construction risk and revenue modelling are all shown to be critical to project viability. While the opportunity is significant, delivery will depend on regulatory certainty, timely decisions, supply chain capacity and confidence that the full system value of pumped storage is recognised.

Beyond new-build projects, the session explores how the UK can extract greater value from its existing hydropower fleet. Raising dams, expanding headponds and making targeted storage improvements can reduce water spillage, improve operational control and increase generation without necessarily adding new turbine capacity. These interventions must be assessed carefully against dam safety, environmental, consenting and commercial constraints, but they could provide a practical route to increasing flexibility from assets already connected to the system.

The panel also considers tidal range, biodiversity, grid response and the relationship between hydropower and battery storage. Rather than viewing different storage technologies as competitors, speakers emphasise that the future system will require multiple layers of flexibility: batteries for very fast response and hydropower for deeper, longer-duration support. Together, these technologies can help make a renewable-led electricity system more operable, secure and resilient.

The session explores

• The role of hydropower in UK energy security and system resilience
• Pumped storage hydropower and long-duration electricity storage
• The cap-and-floor mechanism and investment certainty
• Delivering major new hydro projects at scale
• Increasing storage and flexibility from existing hydro assets
• Tidal range, sovereign capability and long-term infrastructure value
• The complementary roles of batteries and hydropower in balancing the grid

Watch the full session to hear industry experts discuss how large-scale hydropower can support renewable deployment, strengthen system operability and provide the long-duration storage needed for a more secure and resilient UK energy system.

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