Lower skip rates for UK battery storage but NESO plans further reform

UK grid-scale batteries are being skipped at a lower rate than before in Great Britain’s balancing market, following efforts to improve how BESS assets are dispatched by NESO’s control room.

Skip rates for all technologies were 9% lower across January to June 2026, against the same period in 2025. For batteries, skip rates fell from an average of 49% across the first half of 2025 to 38% for the same period in 2026. Pumped storage skip rates were also down, from 59% to 49%.

Skipping occurs when the control room selects a more expensive asset to carry out a balancing action that could have been delivered at a lower cost by, for example, a grid-scale battery. Not all skips are avoidable, as control room engineers need to consider factors such as system constraints, asset availability and network conditions when making decisions.

The issue is a longstanding one for battery asset owners, with leading developers signing an open letter in 2024 that claimed utility-scale batteries were being ignored in favor of more costly gas-fired peaker plants.

NESO acknowledges this issue but notes that skip rates are complex as they are not driven by a single issue and therefore can’t be solved by a single intervention according to the grid operator.

Operational changes at NESO and adjustments to the grid code signed off by regulator Ofgem have led to lower skip rates.

Changes include improved communication protocols for how batteries trading in the balancing mechanism communicate their availability to NESO, introduced in November 2025.

NESO expects further improvements will be achieved through changes to systems, processes and methodologies, but warned that the low hanging fruit has already been picked.

The reduced skip rate comes during what was described as a “monumental year” for grid-scale electricity storage in the UK government’s update on clean flexibility progress. Great Britain’s grid-scale battery fleet reached 7.5 GW in power capacity by the end of 2025, according to the UK government, with 23 GW to 27 GW targeted for 2030.

More changes to how batteries trade in Great Britain are anticipated. NESO is working with regulator Ofgem to investigate balancing and dispatch reform, network constraint management options, and stronger locational investment signals under the new Reformed National Pricing initiative.

Changes for battery owners could include lowering the capacity threshold mandatory participation in the Balancing Mechanism market and changes to market trading deadlines.

NESO will also investigate why consumer-lead flexibility in areas behind thermal constraints have faced high skip rates, as part of a wider push to provide more practical routes for households and other offtakers to participate in national flexibility markets.

The grid operator will publish skip rate figures for consumer-led flexibility behind thermal constraints in the third quarter of 2026, and complete an impact assessment of previously delivered load response actions to determine next steps.