The Annex A threshold, with the wording “or more”.
CONSULTATION FILE · ENGLAND · 24 AUG—5 OCT 2026
A 100 MW battery could get a second intervention window.
MHCLG is consulting a route for mayoral intervention in major projects, including standalone batteries of 100 MW+. See where the intervention window sits, why the consultation uses 14 days, and what remains only a proposal.
PROPOSAL, NOT LAW
01 / THE PROPOSAL
What does the consultation propose?
A possible mayoral intervention, placed after the local authority's signal.
The Ministry of Housing, Communities and Local Government (MHCLG) consultation describes a three-stage process for applications of potential strategic importance. At Stage 1, the local planning authority refers the application to the mayor for views. Stage 2 is the new point to watch: it begins when the authority is “minded to” grant or refuse.
The proposed route sheet
File / 01
Proposed route
outside London
outside London
01 / REFERRALStage 1Mayor sees the application.
02 / MINDED TOLocal signalGrant or refuse.
03 / 14 DAYS*Intervene?14 days in the consultation; final unit awaits secondary legislation.
04 / IF CALLED INStage 3If called in, further determination.
Energy / threshold
with a condition
with a condition
ANNEX AStandalone batteryThe category is listed.
THRESHOLD100 MW+“100 MW or more”.
CONDITIONSDS adoptedCategory described as available after adoption.
BOUNDARYNot todayConsultation, not a live rule.
London /
Category 3J
Category 3J
HOUSING50+ homesDevelopment threshold.
REFUSALMinded to refuseOnly when refusal is intended.
NO STAGE 1Short routeNo initial response in this case.
COMPARATORNot energySeparate London rule.
02 / THE DECISION POINT
Where do the 14 days sit?
The consultation uses 14 days as an example; the final unit is not fixed.
In paragraph 17, the consultation uses a 14-day window in which the mayor decides whether to intervene or leave the application with the local authority. In paragraphs 62—63, the same document says secondary legislation will change time periods expressed in “days” and “weeks” to “working days”. The published text therefore gives a 14-day example, but does not fix the final duration and time unit of the enacted rules. If the mayor intervenes by “calling in” — taking over the application's determination — the consultation describes a third stage.
The practical question
An application does not automatically enter a second hearing. It must first fall within the relevant category and proposed conditions; at Stage 2, the mayor must choose intervention. This page does not predict whether that choice would be made.
That is why “second window” describes a decision point, not a promise about delay, outcome, or application volume.
03 / ANNEX A
The battery threshold has a condition.
The number is clear. The timing is not yet a rule.
Annex A lists solar, onshore wind, standalone storage, and electricity network projects. For standalone battery storage, the published threshold is 100 MW or more. The same annex says these large-scale infrastructure categories are available following adoption of a strategic development strategy (SDS).
The consultation example for the mayor's decision to intervene or leave the application to the local authority. Secondary legislation may express the final period in working days.
What the threshold does not mean
A 100 MW battery does not receive a separate route today simply because of its capacity. It is a category in a consultation. Between the proposal and an applicable rule sit SDS adoption, legislation, and later procedural rules.
Release formula retained: 100 MW + the operator “or more”; no rounding or derived estimates.
04 / COMPARATOR
London is not the same route.
Category 3J is about housing and an intended refusal.
The consultation treats London separately. Category 3J concerns developments of 50 or more homes where the local authority is minded to refuse the application. It is a streamlined route: no initial Stage 1 referral or formal response is required unless refusal is intended.
| Question | Proposed infrastructure | London / Category 3J |
|---|---|---|
| Visible threshold | Standalone storage: 100 MW or more. | Development: 50 or more homes. |
| Local signal | Authority is minded to grant or refuse. | Authority is minded to refuse. |
| What the mayor does | Uses a 14-day decision example; the final unit follows secondary legislation. | Has a separate streamlined London mechanism. |
| What the comparison does not say | It does not prove that every battery will be called in. | It does not turn Category 3J into an energy rule. |
05 / WHAT REMAINS OPEN
What is known and not known?
The text shows the proposed mechanism; it cannot show its effect yet.
Known
The consultation has a public timetable, uses 14 days as the Stage 2 example, announces working-day wording in secondary legislation, and lists a 100 MW standalone-storage threshold in Annex A. Its geography is England.
Not known yet
We do not yet know the final duration and time unit, how many applications would enter the route, how many mayors would intervene, or whether the proposal will become law in the published form. None of those questions can be replaced with an estimate from the consultation text.
That is why this page tracks the position of a decision in the route, rather than assigning it an outcome.
06 / WHY IT MATTERS
What does the reader gain?
A reading map for a proposal that is easy to mistake for a rule.
Threshold without a shortcut
You can separate the 100 MW capacity from the SDS condition and the question of mayoral intervention.
The exact moment
You can see that the 14-day example appears after the “minded to” signal, not at the start of the application, and that the final unit remains open.
No false promise
You can distinguish an intervention window from a guarantee that a project will stop or be approved.
A fair comparator
You can use Category 3J as a London example without presenting it as a battery rule.
07 / FOLLOW THE TEXT
Source and limits.
One official document, read with its boundaries intact.
-
MHCLG · Planning powers for mayors in England
Published 24 August 2026. The consultation is open until 5 October 2026 and says intended commencement would be in early 2027, subject to consultation and parliamentary scheduling.
Read the official document ↗ Part 1, paragraphs 14—24 · paragraph 39 · Annex A · footnote 6 -
This release's method
The source text is held in a local archive and checked with SHA-256. The visible values are direct transcriptions: the consultation's 14-day example, 100 MW or more, and 50 or more homes. The final time unit is not presented as enacted law.
View the evidence sheet ↗
Use note
This file explains a public consultation. It is not legal guidance and does not tell an applicant how to avoid referral, intervention, or a planning rule.
In short: the 100 MW threshold is concrete; the intervention window is proposed; the consultation uses 14 days as its example, while the final time unit will come from secondary legislation.