Since December 2024, batteries in Great Britain have saved consumers £188 million: £47 million through the Balancing Mechanism, and a further £141 million from suppressing prices in the wholesale market.

NESO's Reformed National Pricing review is examining how batteries retrade behind constraints, selling into wholesale markets in Scotland and then being instructed to reverse that export in the Balancing Mechanism. Whether that behaviour is a net cost or a net benefit to consumers is one of the open questions in that review, and the whole point of the reform is to reduce consumer cost.

Here we look at the consumer benefit (and cost) of batteries in the Balancing Mechanism and wholesale markets, including batteries behind constraints in Scotland.

Our November 2025 piece valued the Balancing Mechanism benefit at £23 million. This update adds nine more months of data, a revised methodology for reversed Bids, and a first estimate of the wholesale price suppression batteries deliver by displacing gas in wholesale markets.

Key takeaways

• Batteries are a clear net positive for consumers. £188 million in saved costs since December 2024, equivalent to the annual energy bills of roughly 115,000 households (at an average £1,641/year).
• By displacing gas, battery actions in the Balancing Mechanism are saving more money than ever. In April 2026, with an un-congested grid and relatively high gas prices, battery actions saved £8 million.
• Scottish batteries suppress wholesale prices, and that saving outweighs the cost of bidding them off during constraints. Price suppression on those reversed-export MWh (£29 million) more than offsets the cost of reversing them (£25 million) between December 2024 and April 2026. The system sees the greatest benefit during winter months.

For details on the methodology, contact the author at zach@modoenergy.com.

In the Balancing Mechanism, batteries have saved £47 million

In the Balancing Mechanism alone, batteries have now saved consumers over £47 million between December 2024 and April 2026, up from £23 million when we last reported in November 2025. Every month in the window has been net positive.

The savings come from four action types:

• Energy Offers: batteries discharge into the grid at a lower price than the CCGTs or peakers they displace.
• Energy Bids: batteries Bid in at a higher £/MWh than pumped hydro or curtailable wind, so NESO recovers more money from them when they are instructed to charge.
• Utilised System Bids: system-flagged Bids that genuinely absorb constrained generation, displacing wind curtailment.
• Reversed System Bids: the only consistently negative leg. NESO instructs a battery to undo a wholesale-traded export, and pays a different unit a replacement Offer to put that energy back on the system. The replacement Offer cost is what shows up on the consumer's bill.

If you want to understand how these actions work, read our previous analysis.

Recent months show when batteries deliver the most consumer benefit, and when they don't.

Winter 2025/26 was relatively quiet. Wholesale gas prices stayed low through December, January and February, which compressed the spread between battery offer prices and the CCGTs they displaced. Each of the three months landed at £1.2–2.6 million net, well below the £3–5 million highs seen earlier in 2025. When gas is cheap, the gas plants that batteries are beating in the Balancing Mechanism is less expensive to begin with, so the consumer saving on each MWh displaced shrinks.

March 2026 was windy and heavily constrained. Middle East tensions pushed GB gas prices up 67% month-on-month and wind generation averaged 9.7 GW. The wider battery–gas spread drove record Energy Offer benefit (£3.1 million), but Reversed System Bids hit their worst single month at -£3.3 million as NESO managed constraints. Net saving for the month was £2.3 million. Still positive, but dragged heavily by the constraint side.

Batteries saved £7.6 million in April 2026, more than triple March. Wind fell 18% to 8.0 GW while solar generation set a new all-time daily record of 121 GWh on April 30, and gas prices stayed elevated. Less wind meant lower reversed-Bid costs (−£1.3 million). High gas prices kept the battery–gas offer spread wide. Energy Offers alone saved £4.5 million, the highest single-month value seen yet.

March and April 2026 show where the consumer benefit comes from. The saving scales with the price spread between batteries and the gas plant they displace, and shrinks when the grid is heavily constrained.

Replacement Offer costs

When a battery sells power into the wholesale market and is then instructed in the Balancing Mechanism to reduce its output, two cash flows happen:

1. Batteries pay money back to reduce their output. This is a real for consumers.