Super battery projects that maximise renewable-generated power enter next phase of Ofgem’s green power storage scheme

Ofgem is today (Tuesday 23 September) confirming the 77 projects entering the final assessment stage of a government-driven ‘super battery’ support scheme designed to secure investment, promote growth and stop green energy going to waste.  

Long Duration Electricity Storage (LDES) will play a key role in Great Britain’s grid expansion, storing extra renewable energy when the weather conditions are producing more than we need, and use later when the wind is not blowing.  

As the UK accelerates its transition to clean power, we’re all familiar with the technologies at either end of the energy journey — from solar farms and wind turbines generating renewable power, to electric vehicle chargers and heat pumps using it.   

But what’s happening in the middle of that net zero journey is just as vital.  

Innovations in grid infrastructure and LDES are quietly transforming how we manage renewable energy. Unlike fossil fuels, solar and wind power are intermittent — meaning there are times when we generate more energy than we need, and times when we don’t generate enough. LDES projects are designed to meet this challenge.  

Instead of having to pay wind and solar farm operators to stop generating on particularly windy or sunny days, long duration electricity storage can maximise green energy production by providing more innovative ways to store that excess power so the generators can keep running for longer.  

This stored electricity can then be used later when the weather changes and there isn’t enough renewable generation to meet demand – meaning even more savings for customers with less need to pay gas power stations to switch on to cover the shortfall.  

Supporting a government growth pledge to build major new LDES projects for the first time in 40 years, Ofgem launched a new cap and floor support scheme in April to unlock billions in investment and boost Great Britain’s tech economy.  

An initial group of 171 projects applied to the scheme and today the regulator is confirming that 77 applications are eligible to progress to the second phase of the process. These projects include a variety of storage methods such as Li-Ion batteries, flow batteries and pumped hydro storage, which releases water stored at height to turn turbines, creating electricity to power millions of homes across the country.  

This diversity of technologies can all play a crucial role in delivering a cleaner, more efficient and secure energy system with the capacity to bring balance to Britain’s renewable energy production, whatever the weather.   

Beatrice Filkin, Director of Major Projects Infrastructure for Ofgem, said:    

“Renewable power is the key to seizing control of our own energy system and end the costly reliance on the turbulent wholesale gas market, so we don’t want to see a single watt go to waste.  

“That’s why we need to boost our ability to store as much homegrown energy as we can to let the turbines keep turning when the wind is at its strongest - and on the days when the gusts drop and the sun doesn’t shine that reserve of excess clean power can be called upon.  

“There’s lots of different ways you can do this – with batteries, compressed air or pumped hydro storage – and we’ll consider them all, as this technology is vital for a modern energy system.   

“Through Ofgem’s cap and floor process we are beginning to identify the projects that we think are best placed to capture and make the most of our precious natural resources, so that we can have safe, secure and good value-for-money power.”  

Energy Minister Michael Shanks said:  

“This is another huge step forward in reversing the legacy that has seen no new long duration storage built for 40 years – a technology that will see Britain take back control of its energy supply and protect billpayers for good.  

“By scaling this up, we can transform the way electricity is supplied in this country when demand is high - using stored up low-cost, homegrown solar and wind power to help end our reliance on costly fossil fuel markets once and for all.”  

As the remaining applications move forward to the next stage, Ofgem will request more detailed information set out in the Final Project Assessment Framework, published today, before the successful projects are confirmed in the summer of 2026.  

Notes to editors  

Long-Duration Electricity Storage (LDES) refers to energy storage systems that can store and release electricity for long periods, defined as eight hours or more. These systems help balance the supply and demand of electricity, especially when using renewable energy sources like wind and solar, which can be unpredictable.   

Long-duration electricity storage has multiple benefits:  

• It allows a greater amount of cheap renewable power to be integrated into the electricity system, lowering the overall cost of electricity for consumers
• Provides power capacity that can be switched on and off, making the grid more flexible 
• It avoids the waste when renewables have to be curtailed due to excess supply or congestion on the grid – resulting in constraint payments to windfarm operators  
• It provides electricity system services to the grid, such as the ability to restart after power failures or stability services to keep the lights on in real time  
• If the UK establishes a strong domestic energy storage industry, it can export storage capacity and technologies
• Storage would reduce the UK’s dependence on costly, polluting and uncertain fossil fuel imports

 Great Britain currently has 2.8 gigawatts (GW) of LDES across four Pumped Storage Hydro (PSH) facilities in Scotland and Wales. These operate like natural batteries, with electricity stored by pumping water up a mountain to be released when required and are already crucial to the electricity system. Other forms of LDES – such as liquid air energy storage (LAES), compressed air energy storage (CAES), Li-Lon and flow batteries – are also being developed.    

In October 2024, the government decided to introduce an LDES investment support scheme to be delivered by Ofgem. The cap and floor investment support scheme was strongly supported by the consultation responses and is modelled upon the approach already used to successfully deliver electricity interconnection.    

Ofgem opened the first application window in April 2025, screening projects for eligibility against a clear set of published criteria to ensure a fair and transparent process for all.     

The regulator is now asking the projects which meet the initial criteria to submit more detailed bids for final assessment. We expect to make final decisions on which projects can get cap and floor investment support in the summer of 2026.    

Cap and Floor is a regulatory scheme to be used to support these projects:  

• Cap: The cap is a quid pro quo arrangement that sets a maximum revenue and sees projects pay money to consumers if they end up making more than is considered a fair rate of return on invested capital.  
• Floor: This is the minimum revenue provided to the project. If the project's revenue falls below this floor, consumers pay the LDES operator the difference up to the floor level.   

Being awarded a cap and floor means the project is underwritten to provide financial protection on the downside. It ensures that the project can earn a minimum income to recover their investment. If revenue is high, consumers are rewarded with the excess revenue being shared with consumers.