Grid early warnings: electricity and gas notices
When the electricity or gas system operator expects supply to be tighter than it would like, it publishes a notice asking the market for more. This page shows whether one is in force and lists the recent ones. A notice is an early, routine request, not a warning of power cuts, and most are cancelled within hours.
This is the normal state. No Electricity Margin Notice or other system-margin notice from NESO, and no Gas Deficit Warning, Gas Balancing Notification or Gas Balancing Alert from National Gas for gas day 13 November 2026 or the next.
Newest NESO system warning of any kind published at 12:24 on 12 November 2026; National Gas notices last published at 04:55 on 13 November 2026. Checked twice a day, so a notice issued and cancelled between checks appears in the list below but may never show here.
Notices in the last 12 months
NESO issued 7 Electricity Margin Notices since 13 November 2025, and 7 were cancelled. A notice is often re-issued as the forecast changes; each line below is one notice with its updates folded in.
- CancelledElectricity Margin Notice3 updates
Electricity Margin Notice for 08:00 to 11:00 on Monday 9 November 2026, issued at 19:17 on Sunday 8 November 2026. NESO forecast the spare margin falling 1,388 MW short of what it wants in hand, revised to 200 MW in its last update, and asked generators for more. Cancelled at 09:11 on Monday 9 November 2026.
- CancelledElectricity Margin Notice4 updates
Electricity Margin Notice for 16:00 to 23:00 on Tuesday 6 October 2026, issued at 23:59 on Monday 5 October 2026. NESO forecast the spare margin falling 1,840 MW short of what it wants in hand, revised to 321 MW in its last update, and asked generators for more. Cancelled at 15:51 on Tuesday 6 October 2026.
- CancelledElectricity Margin Notice2 updates
Electricity Margin Notice for 16:00 to 19:00 on Monday 28 September 2026, issued at 00:26 on Monday 28 September 2026. NESO forecast the spare margin falling 1,400 MW short of what it wants in hand, revised to 104 MW in its last update, and asked generators for more. Cancelled at 15:02 on Monday 28 September 2026.
- CancelledElectricity Margin Notice3 updates
Electricity Margin Notice for 18:00 to 20:00 on Wednesday 12 August 2026, issued at 22:30 on Tuesday 11 August 2026. NESO forecast the spare margin falling 1,760 MW short of what it wants in hand, revised to 1,200 MW in its last update, and asked generators for more. Cancelled at 12:57 on Wednesday 12 August 2026.
- CancelledElectricity Margin Notice3 updates
Electricity Margin Notice for 18:30 to 22:30 on Thursday 9 July 2026, issued at 21:31 on Wednesday 8 July 2026. NESO forecast the spare margin falling 1,200 MW short of what it wants in hand, revised to 900 MW in its last update, and asked generators for more. Cancelled at 19:30 on Thursday 9 July 2026.
- CancelledElectricity Margin Notice3 updates
Electricity Margin Notice for 19:00 to 22:00 on Friday 26 June 2026, issued at 00:30 on Friday 26 June 2026. NESO forecast the spare margin falling 671 MW short of what it wants in hand, revised to 100 MW in its last update, and asked generators for more. Cancelled at 21:41 on Friday 26 June 2026.
- CancelledElectricity Margin Notice2 updates
Electricity Margin Notice for 19:00 to 22:00 on Wednesday 24 June 2026, issued at 22:04 on Tuesday 23 June 2026. NESO forecast the spare margin falling 1,900 MW short of what it wants in hand, revised to 1,450 MW in its last update, and asked generators for more. Cancelled at 14:20 on Wednesday 24 June 2026.
National Gas: no Gas Deficit Warning, Gas Balancing Notification or Gas Balancing Alert in the last 12 months. Its data portal shows no active value for these items on any day in its published series.
Times are UK time. The plain-English lines are ours, read from the notices' own text: period, shortfall and cancellation. Sources: NESO system warnings on Elexon BMRS, National Gas Data Portal.
Everything NESO published, by type
Most of NESO's system warnings are routine operational messages for the industry. Only the margin notices are about whether there is enough supply in hand.
| Type | Messages | Notices |
|---|---|---|
| System operator trades with neighbouring grids | 360 | — |
| IT systems outage | 126 | — |
| Electricity Margin Notice | 27 | 7, 7 cancelled |
| Other operational notices | 27 | — |
| Negative Reserve Active Power Margin (too much generation in a region) | 5 | — |
Since 13 November 2025. “Messages” counts every publication, including re-issues and cancellations; “notices” counts each margin notice once.
What a notice means, and what it does not
It asks for more generation. An Electricity Margin Notice says that NESO's forecast of spare capacity for a period, usually a few hours around a peak, is short of the margin it wants in hand. In the notice's own words it is issued “to encourage market actions to increase System Margins”. Generators, storage and interconnectors respond, and the margin usually recovers.
It is not a warning that the lights will go out. It is the earliest and mildest of NESO's system-margin warnings, and the usual outcome is a cancellation, often within a few hours. In the last 12 months 7 of 7 were cancelled.
No notice does not mean nothing can happen. Notices cover a forecast shortfall, and sudden events are not forecast. On 23 June 2026 grid frequency fell to about 49.66 Hz at around 8pm, against the normal 50 Hz (Elexon system frequency data), with no margin notice in force; the next notice was issued that night, for the evening of 24 June (Elexon system warnings).
Most power cuts have nothing to do with it. The cuts most households see are local: a fault or storm damage on the local network, which a national notice is not about. Our power cuts tracker follows those.
Nothing different. There is nothing to buy and nothing to switch off. The sensible preparation is the same on any day: a torch, a charged power bank and the 105 number to report a power cut. Preparing for a power cut →
Common questions
What is an Electricity Margin Notice?
It is a notice from NESO, the National Energy System Operator, that the spare generating capacity it wants in hand for a period (usually a few hours at a peak) is forecast to fall short. In NESO's own wording it is issued "to encourage market actions to increase System Margins": it asks generators and other providers to offer more. It is an early, routine tool, not an emergency measure.
Does a margin notice mean there will be power cuts?
No. A notice is a request to the market for more generation, and the usual outcome is that enough is offered and the notice is cancelled. Of the 7 Electricity Margin Notices NESO issued in the last 12 months, 7 were cancelled. The power cuts most households see are local, a fault or storm damage on the local network, and a national notice is not about those.
If there is no notice, does that mean the grid is fine?
Not necessarily. A notice covers one specific risk, a forecast shortfall in spare capacity, and sudden events are not forecast. On 23 June 2026 grid frequency fell to about 49.66 Hz at around 8pm, a sharp dip from the normal 50 Hz, with no margin notice in force beforehand; the next margin notice was issued that night, for the evening of 24 June.
What are the gas notices?
National Gas, which runs Britain's gas transmission system, can issue a Gas Deficit Warning or a Gas Balancing Notification when supply and demand on the system look out of balance. In National Gas's own description, the intent is "to stimulate a market response to address the NTS physical imbalance": more gas brought onto the system, or less taken off. Its data portal shows none in the last 12 months.
Should I do anything when a notice is issued?
There is nothing to buy and nothing to switch off. The sensible step is the same any day: be ready for an ordinary local power cut, with a torch, a charged power bank and the 105 number to report a cut. Our national power outage guide covers what a much rarer, wider outage would involve.
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- NESO, GB transmission system warnings, published on Elexon BMRS and read from the Elexon Insights API (SYSWARN). Notices are paired with their cancellations by the period they cover; that pairing and the plain-English lines are ours.
- National Gas, Transmission Data Portal: Gas Deficit Warning (PUBOBJ2054/2055), Gas Balancing Notification (PUBOBJ111154/111155) and GBA Alert Level (PUBOB1546/1547), today and tomorrow. The Margins Notice is not shown: the portal publishes its trigger level, not whether a notice is in force.
- Elexon, system frequency (15-second readings), for 23 June 2026.
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For a web pageSource: <a href="https://www.preparedbritain.co.uk/trackers/grid-warnings">PreparedBritain grid early warnings tracker</a>Source: PreparedBritain grid early warnings tracker, https://www.preparedbritain.co.uk/trackers/grid-warningsThe page names the official source behind each figure. Need a chart or a breakdown? hello@preparedbritain.co.uk
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