United Kingdom - From battery pioneer to storage powerhouse
6 min read
The UK energy storage market has undergone a transformation. From experimental grid-balancing pilots less than a decade ago to now leading Europe in installed and planned battery energy storage system (BESS) capacity, the UK has cemented its position as one of the most dynamic and mature BESS markets in the world.
According to European Commission data and analysts at Rho Motion, only China and the U.S. had more operational capacity by the end of 2024. What began with the first Enhanced Frequency Response auction in 2016 has evolved into a sector characterized by deep revenue stacks, intense competition, and a multibillion-pound project pipeline.
The UK’s geography makes its grid uniquely dependent on flexible resources. As an island with limited interconnection, the power system has long wrestled with issues like frequency control, inertia, and reserve.
Three features of the UK power market accelerated storage deployment:
Robust wholesale markets with deep liquidity
A state-backed capacity market offering long-term revenue certainty
A congested and aging grid that desperately needs flexibility
These conditions helped propel the UK to deploy 812 MWh of BESS in Q4 2024 alone, with total power capacity expected to reach 6 GW by 2025 — and 23 GW by 2030.
The early years were lucrative. Between 2020 and 2022, frequency response services set the pace, with BESS earning upwards of £220,000/MW/year. First movers cashed in while competing primarily against gas units.
But in late 2022, supply began to outstrip demand for ancillary services — batteries were competing against each other, not gas. This marked a revenue phase shift, where the economics pivoted from one market to many.
Today, developers are shifting toward:
2–2.5 hour duration systems for wholesale trading
Multi-market strategies combining frequency, wholesale, balancing, and tolling
Business models optimized for merchant volatility and long-term resilience
As merchant risk grows, investors and lenders are looking for structure and clarity. Long-term offtake agreements, tolling deals, and smart optimization partnerships are now key tools to de-risk revenue streams.
In 2024, Gresham House and Octopus Energy inked a two-year tolling deal for 568 MW/920 MWh, signaling strong institutional appetite for fixed-revenue frameworks. However, experts say tolls won’t be the main route for everyone — they work well for dividend-paying funds or early-stage developers seeking debt, but the broader market will still rely on competitive optimization and merchant plays.
Crucially, lenders have matured in how they assess projects. It's no longer just about today's returns, but a narrative of operational strategy, optimizer performance, and long-term viability.
While the lithium-ion BESS build-out continues at pace, the UK is also preparing for the next frontier: long-duration energy storage (LDES). The government’s cap-and-floor support scheme, launched in 2025, aims to unlock "billions" in investment and support:
Pumped hydro
Flow batteries
Compressed and liquid air storage
Projects must meet 8-hour duration thresholds, with 100 MW minimums for established tech and 50 MW for emerging solutions. It’s the first major LDES incentive in the UK in 40 years and sets the stage for diversification beyond lithium-ion.
The UK has proven that it’s possible to go from early pilots to a robust and dynamic BESS market in less than a decade. The question now is: Will other European countries follow suit?
With an evolving policy landscape, a maturing investor base, and a culture of regulatory innovation, the UK may offer the most instructive template for what a high-performing storage market can look like.
And as batteries become the backbone of clean power systems, Great Britain isn’t just playing catch-up it’s helping to define the playbook.
The Re-Twin Energy Team supports developers, investors, and operators across Europe in building future-proof BESS strategies — from market intelligence to project modeling and optimizer assessment.
The UK energy storage market has undergone a transformation. From experimental grid-balancing pilots less than a decade ago to now leading Europe in installed and planned battery energy storage system (BESS) capacity, the UK has cemented its position as one of the most dynamic and mature BESS markets in the world.
According to European Commission data and analysts at Rho Motion, only China and the U.S. had more operational capacity by the end of 2024. What began with the first Enhanced Frequency Response auction in 2016 has evolved into a sector characterized by deep revenue stacks, intense competition, and a multibillion-pound project pipeline.
The UK’s geography makes its grid uniquely dependent on flexible resources. As an island with limited interconnection, the power system has long wrestled with issues like frequency control, inertia, and reserve.
Three features of the UK power market accelerated storage deployment:
Robust wholesale markets with deep liquidity
A state-backed capacity market offering long-term revenue certainty
A congested and aging grid that desperately needs flexibility
These conditions helped propel the UK to deploy 812 MWh of BESS in Q4 2024 alone, with total power capacity expected to reach 6 GW by 2025 — and 23 GW by 2030.
The early years were lucrative. Between 2020 and 2022, frequency response services set the pace, with BESS earning upwards of £220,000/MW/year. First movers cashed in while competing primarily against gas units.
But in late 2022, supply began to outstrip demand for ancillary services — batteries were competing against each other, not gas. This marked a revenue phase shift, where the economics pivoted from one market to many.
Today, developers are shifting toward:
2–2.5 hour duration systems for wholesale trading
Multi-market strategies combining frequency, wholesale, balancing, and tolling
Business models optimized for merchant volatility and long-term resilience
As merchant risk grows, investors and lenders are looking for structure and clarity. Long-term offtake agreements, tolling deals, and smart optimization partnerships are now key tools to de-risk revenue streams.
In 2024, Gresham House and Octopus Energy inked a two-year tolling deal for 568 MW/920 MWh, signaling strong institutional appetite for fixed-revenue frameworks. However, experts say tolls won’t be the main route for everyone — they work well for dividend-paying funds or early-stage developers seeking debt, but the broader market will still rely on competitive optimization and merchant plays.
Crucially, lenders have matured in how they assess projects. It's no longer just about today's returns, but a narrative of operational strategy, optimizer performance, and long-term viability.
While the lithium-ion BESS build-out continues at pace, the UK is also preparing for the next frontier: long-duration energy storage (LDES). The government’s cap-and-floor support scheme, launched in 2025, aims to unlock "billions" in investment and support:
Pumped hydro
Flow batteries
Compressed and liquid air storage
Projects must meet 8-hour duration thresholds, with 100 MW minimums for established tech and 50 MW for emerging solutions. It’s the first major LDES incentive in the UK in 40 years and sets the stage for diversification beyond lithium-ion.
The UK has proven that it’s possible to go from early pilots to a robust and dynamic BESS market in less than a decade. The question now is: Will other European countries follow suit?
With an evolving policy landscape, a maturing investor base, and a culture of regulatory innovation, the UK may offer the most instructive template for what a high-performing storage market can look like.
And as batteries become the backbone of clean power systems, Great Britain isn’t just playing catch-up it’s helping to define the playbook.
The Re-Twin Energy Team supports developers, investors, and operators across Europe in building future-proof BESS strategies — from market intelligence to project modeling and optimizer assessment.
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