What It Costs to Balance the Great Britain Grid
See what it costs to keep electricity supply and demand in balance, including the cost of working around congested parts of the grid.
What balancing the grid means
The wholesale market settles most of the country’s electricity in advance: generators contract to produce, suppliers contract to buy, and in theory the two match. In practice they never quite do. Demand comes in above or below forecast, a plant trips, the wind arrives an hour late.
The system operator closes the gap by paying generators to increase or reduce output and by buying reserve and stability services.
The balancing bill
These are complete settlement months only. Where the published data is missing periods, the month is left out rather than charted low — a partial month plotted next to full ones reads as a fall in cost that did not happen.
Monthly balancing cost data status
Current- Content period:
- 12 months to September 2026
- Last successful retrieval:
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Great Britain · NESO balancing cost data
£2.8bn spent balancing the grid over 12 complete months
Electricity has to be balanced second by second, and the network cannot always move power to where it is needed. These are the costs the system operator incurs doing that — recovered through BSUoS charges, not billed to homes directly.
Last 12 complete months
£2.8bn
of balancing cost, Aug 2025 to Sept 2026, with 2 incomplete months excluded
Largest single cause
87.3%
constraints, across all 37 complete months (Apr 2023 to Sept 2026, with 5 incomplete months excluded)
Spread across every meter
£89.23
per electricity meter over 12 complete months (Aug 2025 to Sept 2026, with 2 incomplete months excluded) — our calculation, not a bill line
Measured data
1,306
settlement days, half hour by half hour — every month held, complete or not
What the money is spent on
Across every complete month held — 37 complete months between Apr 2023 and Sept 2026 — a 42-month calendar span, because Mar 2024, Jul 2024, Nov 2024, Mar 2026 and Jun 2026 are missing settlement periods and are left out. That is a longer window than the headline total above, which is the most recent twelve complete months only, so the two are not shares of the same number.
| Category | Cost | Share | Periods earning money back |
|---|---|---|---|
| ConstraintsPaying generators to turn down, and others to turn up, when the network cannot move power to where it is needed. | £6,108.4m | 87.3% | 287 |
| Positive reserveHolding generation and demand response in readiness in case the system falls short. | £484.9m | 6.9% | 1,170 |
| Other balancing servicesRemaining balancing services, including smaller system requirements. | £219.6m | 3.1% | 3,383 |
| Frequency controlKeeping grid frequency within its statutory range second by second. | £82.1m | 1.2% | 2,221 |
| Energy imbalanceBuying or selling energy to close the gap between what was contracted and what the system actually needed. | £74.9m | 1.1% | 29,333 |
| Negative reserveHolding the ability to reduce generation quickly if demand falls away. | £29.1m | 0.4% | 3,900 |
Month by month
Only complete months are charted. 6 months had settlement periods missing from the published data and are left out, so a gap is never shown as a fall in cost.
| Month | Cost | Relative size |
|---|---|---|
| Apr 2023 | £141.4m | |
| May 2023 | £77.7m | |
| Jun 2023 | £63.2m | |
| Jul 2023 | £178.3m | |
| Aug 2023 | £121.7m | |
| Sept 2023 | £179.1m | |
| Oct 2023 | £275.4m | |
| Nov 2023 | £176.9m | |
| Dec 2023 | £185.3m | |
| Jan 2024 | £151.7m | |
| Feb 2024 | £124.8m | |
| Apr 2024 | £162.3m | |
| May 2024 | £85.2m | |
| Jun 2024 | £159.5m | |
| Aug 2024 | £245.5m | |
| Sept 2024 | £126.4m | |
| Oct 2024 | £223.6m | |
| Dec 2024 | £270.9m | |
| Jan 2025 | £149.0m | |
| Feb 2025 | £219.7m | |
| Mar 2025 | £188.0m | |
| Apr 2025 | £94.7m | |
| May 2025 | £161.6m | |
| Jun 2025 | £278.6m | |
| Jul 2025 | £119.9m | |
| Aug 2025 | £185.1m | |
| Sept 2025 | £231.4m | |
| Oct 2025 | £265.0m | |
| Nov 2025 | £209.5m | |
| Dec 2025 | £188.4m | |
| Jan 2026 | £233.2m | |
| Feb 2026 | £148.3m | |
| Apr 2026 | £249.4m | |
| May 2026 | £186.2m | |
| Jul 2026 | £243.5m | |
| Aug 2026 | £193.3m | |
| Sept 2026 | £505.3m |
How we worked out the per-meter figure
This is our own calculation, not an official statistic, so here is all of it.
- Numerator
- £2,838,616,782.31 of balancing cost across 12 complete months between Aug 2025 and Sept 2026 — a 14-month calendar span, because Mar 2026 and Jun 2026 are missing settlement periods and are left out.
- Denominator
- 31,810,780 Great Britain electricity meters, domestic and non-domestic, from DESNZ subnational electricity consumption (2024).
Formula: balancing cost over the complete months shown, divided by every Great Britain electricity meter (domestic and non-domestic), because BSUoS is recovered across all users of the transmission system.
Suppliers recover these costs in proportion to how much electricity is used, so this flat average is not what any particular home pays.
How to read this data
- These are the costs of balancing the transmission system, recovered through BSUoS charges — not a line on a household bill.
- Constraint costs are paid when the network cannot move power to where it is needed. They are not a payment for electricity consumed.
- A category total can be negative for a period, because some balancing actions earn money back. Sign is preserved rather than clamped.
- Months where the publisher has missing settlement periods are marked incomplete and left out of headline totals, so a gap never reads as a fall in cost.
- Any per-meter figure is an Energy Review calculation, shown with its numerator, denominator and formula. Suppliers recover these costs in proportion to consumption, so it is not what any particular home pays.
- Great Britain only. Northern Ireland operates in a separate electricity market.
Source: National Energy System Operator — Daily Balancing Services Use of System (BSUoS) Cost Data. Great Britain transmission-system balancing costs. Licence: National Energy SO Open Data Licence v1.0. Supported by National Energy SO Open Data.
Constraints: paying wind farms to stop
Wind generation is concentrated in Scotland and offshore, while much of the demand is farther south. When the network cannot carry all of that power, the system operator can pay wind farms to reduce output and generators elsewhere to increase it. These payments appear in the constraint cost shown above.
Why the cost has grown
Three structural changes push this bill up, and none of them is a failure of anyone’s day-to-day operation.
- Generation moved away from demand. Coal and gas plants were built near cities and coalfields. Wind is built where the wind is. The distance between supply and demand has grown, and the network was laid out for the old pattern.
- Wind is variable and imperfectly forecast. A forecasting error on a large wind fleet is a large error in megawatts, and someone has to be paid to cover it in real time.
- The old plants provided stability as a by-product. Large spinning turbines held the system’s frequency steady simply by being heavy and turning. Wind and solar do not, so stability now has to be bought as a service rather than arriving free with the electricity.
Who pays, and how it reaches your bill
These costs are recovered through a charge on electricity suppliers, set in proportion to how much electricity their customers use. Nobody is billed for balancing directly; it arrives inside the price of a unit.
Frequently asked questions
What is wind curtailment?
It is the electricity system operator instructing a wind farm to generate less than it could. It usually happens because the network cannot carry the power from where it is being made to where it is needed — most often across the boundary between Scotland and England — so generation on the far side has to come down and generation on the near side has to go up.
Why do wind farms get paid to switch off?
Because they are being asked to stop selling electricity they had already contracted to sell. Generators offer a price at which they will reduce output, the system operator accepts the ones it needs, and the accepted price is what gets paid. The same auction works in the other direction: plant asked to generate more is paid to do so.
Does curtailment mean the electricity was wasted?
It means it was not generated. A curtailment payment buys something real — the network stays inside its limits — and the alternative is building enough network capacity that a constraint never occurs, which costs considerably more than the payments it would avoid. Whether any particular payment is good value is a judgement these figures hand back rather than make.
What are grid balancing costs?
What the electricity system operator spends keeping supply and demand matched in real time and working around a network that cannot always move power to where it is needed. It pays generators to turn up, turn down or stand ready, half hour by half hour, and the total is published as the balancing cost.
Do balancing costs go on my energy bill?
Yes, indirectly. Suppliers pay the charge in proportion to the electricity their customers use and recover it through their tariffs. It is a small share of a typical electricity bill next to the wholesale cost of the energy itself, but it is not nothing, and it has grown.
