The UK’s journey to net zero will be impossible without large-scale energy storage. As renewables like wind and solar become dominant sources of electricity, storing excess power and deploying it when demand is high is critical. From mountainous pumped hydro to cutting-edge cryogenic and compressed air technologies, the UK is deploying a broad portfolio of energy storage solutions to ensure energy security, decarbonisation, and grid resilience.
In this guide, we explore the most important and emerging technologies behind UK energy storage.
1. Pumped Hydro Storage:
What is pumped hydro?
Pumped hydro is a proven and mature form of long-duration energy storage. It works by using surplus electricity to pump water from a lower to an upper reservoir. When energy demand rises, operators release the water back downhill through turbines to generate electricity, effectively turning the system into a giant rechargeable battery.
Existing facilities
The UK currently operates four pumped hydro stations, totalling around 2.8 GW of capacity. These are:
- Dinorwig Power Station (Wales): Dinorwig is Europe’s largest pumped storage hydro (PSH) facility, with a capacity of 1,728 MW and 9.1 GWh of storage. Built inside Elidir Fawr mountain, it is capable of reaching full output in just 16 seconds. It is currently undergoing a £1 billion refurbishment to will extend its operational life by 25 years.
- Cruachan Power Station (Scotland): Located within Ben Cruachan, it has a capacity of 440 MW and 7.6 GWh of storage, powered by four turbines. A £80 million upgrade is underway to modernise two turbines and increase capacity to 480 MW by 2026.
- Ffestiniog Power Station (Wales): The UK’s first PSH plant, Ffestiniog provides 360 MW of capacity and 7.6 GWh of storage. It operates between two reservoirs (Llyn Stwlan and Tan-y-Grisiau). It undergoing a a joint £1 billion refurbishment with Dinorwig, with two of its four units already rebuilt.
- Foyers Power Station (Scotland): Foyers delivers 300 MW of capacity and 6.4 GWh of storage using water from Loch Mhor. Its two 150 MW reversible turbines can start generating in under 30 seconds and provides power to around 68,000 homes annually.
New projects in the pipeline
After more than four decades without new long-duration energy storage projects in the UK, recent policy shifts and a growing recognition of the necessity of storage in a renewables-based energy system has catalysed a new wave of pumped hydro developments:
- Coire Glas (SSE): A landmark 1.3 GW/30 GWh site near Loch Lochy, expected online by 2030–31.
- Glen Earrach Energy: A proposed 2 GW/30 GWh plant near Loch Ness, with public consultations complete and environmental assessments underway.
- Earba Project: A 1.8 GW/40 GWh facility approved in March 2025, expected to take around 6–7 years to build.
- Fearna Project: A 1.8 GW/37 GWh plant, with planning submitted March 2025.
- Balliemeanoch: Currently under development, offering up to 1.5 GW/45 GWh of capacity.
Policy support
A critical development came in April 2025, when Ofgem launched a cap-and-floor scheme for long-duration storage systems. This provides revenue certainty for developers, encouraging private investment and derisking major infrastructure.
NESO projects the UK will need 20 GW of long-duration storage by 2050, with pumped hydro playing a key role in delivering this capacity.
2. Liquid-Air Energy Storage (LAES):
How LAES works
Liquid Air Energy Storage uses off-peak or surplus electricity to cool ambient air, turning it into a liquid. This is stored in insulated tanks. When electricity is needed, the liquid air is warmed, rapidly expanding back into its gaseous form and driving turbines to generate power.
Carrington: The Flagship
The UK’s first commercial LAES facility is under construction by Highview Power in Greater Manchester. Key facts:
- It will offer 50 MW / 300 MWh capacity
- £300 million in climate finance has been pledged to support the project
- The company plans to begin commercial operation of the facility in early 2026
This marks a significant milestone in demonstrating the viability of alternative storage models operating at grid scale.
The road ahead
Highview Power plans to develop four more LAES facilities, each with around 2.5 GWh of storage, bringing 10 GWh of new capacity online by 2030. These facilities are attractive due to their modularity, long design life (30+ years), and use of existing industrial sites.
3. Compressed Air Energy Storage (CAES):
What is CAES?
CAES uses surplus electricity to compress air and pump it into underground cavities, typically salt caverns. When energy demand rises, the compressed air is expanded and released through turbines to generate electricity. Storelectric specialises in CAES technology. Our green CAES system can capture and reuse the heat generated during compression to improve efficiency, meaning our system doesn’t use any fossil fuels.
UK Progress
Though the UK has no active CAES projects, momentum is building:
- Ofgem’s cap-and-floor mechanism includes CAES among eligible long-duration storage technologies.
- Our patented CAES technology is exceptionally well-suited to the UK, which has over 1,000 suitable salt caverns nationwide. Integrating CAES into the UK’s energy system would significantly enhance long-duration energy storage capacity, working alongside PSH, LAES and BESS to meet the demands of Britain’s mass electrification, particularly across major industrial hubs.
4. Battery Energy Storage Systems (BESS):
Why batteries matter
Battery energy storage infrastructure, currently dominated by lithium-ion, is essential for short-to-medium duration grid services, helping balance variable generation, regulate frequency, and offering rapid response grid support.
The explosive growth of BESS
- As of May 2024, the UK had 8.7 GW of BESS capacity either operational or under construction, compared to approximately 2.1 GW in 2020.
- Over 30 GW has already secured consent, and by the end of 2023 the project pipeline reached 95 GW.
Key projects
- Bramley BESS (Hampshire): 100 MW / 331 MWh, currently the UK’s largest energy storage project.
- Fidra Energy (Thorpe Marsh): A 1.4 GW / 3.1 GWh BESS being built on a former coal site.
- Copenhagen Infrastructure Partners (CIP): Two 500 MW / 3 GWh systems planned in Scotland.
- Invinity Energy Systems: A 20.7 MWh vanadium flow battery in Southeast England, operational by 2026, demonstrating non-lithium alternatives for grid-scale energy storage.
- Apatura Projects: Systems near Glasgow (150 MW) and Stirling (400 MW) are in development.
5. The Future of UK Energy Storage
The UK government and regulators now recognise storage as a critical enabler of net zero. For a system powered by renewables, the ability to store and dispatch electricity flexibly is absolutely vital.
What comes next? Our projected timeline:
- 2025–26: LAES Carrington begins operations; Invinity’s flow battery comes online. Cap-and-floor mechanism announces its first projects.
- 2026–27: Construction milestones for pumped hydro projects like Glen Earrach, Earba and Fearna, the first UK CAES plant comes online[EC1] .
- By 2030: Coire Glas and other long-duration systems enter service; multiple LAES plants operational; battery build-out accelerates.
- By 2050: Achieve 20 GW of long-duration energy storage, supporting a 100% clean power grid.
A Multi-Technology approach to Energy Resilience
From the caverns of Teesside and the reservoirs of Scotland to futuristic cryogenic tanks near Manchester, the UK is assembling a flexible, secure and low-carbon energy storage landscape. Pumped hydro is being revitalised, LAES is commercialising, CAES is advancing from concept to pilot, and batteries are being deployed at unprecedented scale.
This multi-pronged approach will enable the UK to harness its vast renewable potential, avoid curtailment costs, and keep the lights on securely, all while cutting carbon emissions and building a greener future.
