The missing infrastructure in the UK’s energy transition

By Ryan Craig, Business Strategy Manager

The case for a more resilient, flexible UK energy system has been building for years.

A new report - New threats and new tools: reinventing energy security for an era of instability* - adds an important perspective to this debate.

The UK’s energy system must be designed not only for normal operating conditions, but for a world where supply chains, infrastructure, and geopolitical relationships are increasingly unpredictable.

Its central message is clear: energy security and the energy transition must be planned together, not treated as competing priorities.

Structural exposure, not just volatility

Around 30% of UK electricity generation relies on gas, leaving consumers exposed to international wholesale markets and price shocks.

At the same time, retiring volumes of ageing gas and nuclear generation through the 2030s will reduce firm capacity, making reliable electricity supply increasingly challenging.

Expanding renewable generation is essential, but on its own it is not enough. Without the ability to store surplus power and deploy it when generation falls, the system remains exposed. More renewable capacity without adequate storage shifts the problem rather than solving it.

The missing piece: long-duration energy storage

The report highlights that long-duration electricity storage (LDES) is a key tool for a resilient power system. As renewable generation grows, the grid will experience periods of abundant supply alongside periods of low output.

Managing this variability requires infrastructure that can capture surplus electricity and return it over days or even weeks. LDES is not a response to a single moment of instability; it is a foundational component of a high-renewable energy system.

From fossil reserves to electricity reserves

For decades, energy security meant holding strategic reserves of oil and gas.  As the UK’s energy system electrifies, it will need an equivalent capability in electricity form: the ability to store large quantities of power and deploy it when required.

Long-duration electricity storage can provide this - storing surplus renewable energy when it is plentiful and making it available when the system needs it most.

Building resilience by design

A decarbonised energy system must maintain reliable supply through prolonged low renewable output and be insulated from global fossil fuel price shocks.

It must also withstand infrastructure and supply chain vulnerabilities. As the report notes, the UK needs a system designed for “stress scenarios, not just normal operations.”

Deploying the full set of flexibility tools is essential, and LDES is one of the few technologies capable of supplying power over multi-day or multi-week events.

In this role, LDES helps stabilise supply while reducing reliance on gas-fired backup generation. Designing the system well means building the tools that allow it to operate reliably for decades to come.

*Report by Public First, produced in collaboration with the Royal United Services Institute (RUSI) and commissioned by RenewableUK.