Grid Pressure Index

This sub-index indicates whether Britain’s electricity networks appear capable of accommodating data-centre and AI-related demand — connection queues, waiting times, known constraints and the investment planned to relieve them.

National indicators published — regional assessment in developmentReporting periods: November 2024 and June 2025Last reviewed: 11 Sep 2026

Ratings are not assigned arbitrarily. Every rating carries a written explanation, a confidence level and a link to the evidence behind it. Where the evidence is not there, the region is rated “Insufficient evidence” rather than guessed.

What the national queue figures do and do not show

The figures below describe contracted demand connection capacity — the capacity that projects hold connection offers for in the Great Britain queue.

It is not electricity currently being consumed.
It is not operational data-centre capacity.
It is not exclusively data-centre demand.
It is not evidence that every queued project will proceed. Ofgem states it is concerned that a significant number of queued projects may not ultimately connect.

A national queue total also cannot establish how much pressure any individual region is under, so it is never used to assign a regional rating.

Ofgem’s consultation on data-centre connection reforms — a commitment fee and data-centre queue milestones — contains proposals, open for response until 16 September 2026. They are not rules in force and are recorded here separately from observed infrastructure data.

National grid indicators

Each reading shows the period the data describes, not the date the document restating it was published. Where a change is shown it is growth in contracted connection offers, not growth in physical grid pressure or in AI electricity use.

Indicators, current values, classification and sources
Indicator	Current value	Reporting period	Previous	Change	Classification	Source	Review status
Data-centre capacity within the GB demand connection queueHow much of the contracted demand connection queue is accounted for by data-centre projects.Figures conflict between Ofgem publications and the reporting date of the data-centre subtotal is not stated. No reading is published.	Insufficient evidence — sources conflict	Not established	—	—	insufficient_evidence	Ofgem — consultation document paragraph 2.7 and press release, 29 July 2026	11 Sep 2026 Next review: 11 March 2027
Total contracted demand in the GB connection queueTotal contracted electricity connection offers held by demand projects in the Great Britain connections queue, across transmission and distribution.This is contracted connection capacity, not electricity being consumed, not operational data-centre capacity and not exclusively data-centre demand. It is not evidence that every queued project will proceed. A national queue total does not establish grid pressure in any particular region.	125 GW	June 2025	41 GW	+204.9%	official	Ofgem — Proposed data centre connection reforms (Curate consultation document), paragraph 2.6	11 Sep 2026 Next review: 11 March 2027

The rating scale

Low pressure
Moderate pressure
High pressure
Severe pressure
Insufficient evidence

Each rating is shown with a written label and a symbol (● Low pressure, ◐ Moderate pressure, ◑ High pressure, ◆ Severe pressure, ○ Insufficient evidence), so it does not depend on colour alone.

Regional grid pressure

Regional evidence collection has started with London and Slough and the Thames Valley. Every region remains rated “Insufficient evidence”: the methodology does not yet define what separates low, moderate, high and severe pressure, and the evidence gathered so far comes from single publishers and describes named substations and grid supply points rather than whole regions. Select a region to read the evidence collected for it, including what each document does not show.

Select a region

London

Insufficient evidence

Evidence collection has begun for London but no pressure rating can be published. The published methodology does not yet define what separates Low, Moderate, High and Severe pressure, and both current evidence records come from a single publisher and describe individual grid supply points rather than the capital as a whole. A national connection-queue total cannot be used to fill that gap.

Connection demand: No London-specific connection-queue figure has been established. The 125 GW Great Britain queue figure is national and is not apportioned to any region.
Known delays: No published average connection waiting time for London has been established. Individual delayed projects are not used to infer one.
Network constraints: UK Power Networks records Bow (E15) as expected to be overloaded under an N-1 outage condition from winter 2026 because of limited transformer capacity, and records a capacity deficiency in the adjoining SSEN network in West London affecting Willesden Grid (NW10). Both are individual sites, not a London-wide position.
Planned investment: Flexibility procurement is the approved route at both sites. No investment figure is published in the source document.
Flexible connections: UK Power Networks reports procuring flexibility at both Bow and Willesden Grid, with 90% of the 2026/27 Bow requirement recorded as procured.

Confidence: lowLast reviewed: 11 Sep 2026UK Power Networks — DNOA Outcomes Report, March 2025

Slough and the Thames Valley

Insufficient evidence

Evidence collection has begun for Slough and the Thames Valley but no pressure rating can be published. The published methodology does not yet define what separates Low, Moderate, High and Severe pressure, and both current evidence records come from a single SSEN consultation draft covering the Iver 132kV grid supply point area rather than Slough alone.

Connection demand: SSEN states that over 600 MVA of data centres are already connected and contracted with capacity across the Iver 132kV grid supply point, with the majority of that load coming from the Slough area. The figure covers the whole grid supply point area, combines connected with contracted capacity, and is stated in MVA.
Known delays: No published average connection waiting time for this area has been established.
Network constraints: Both 132/33kV transformers feeding Chalvey bulk supply point are forecast to overload under an N-1 condition, in a year varying between 2030 and 2041 depending on the scenario applied.
Planned investment: Reinforcement options are identified — a third 132/33kV transformer and a 132kV circuit from the proposed Langley Hall switching station — but no funding, cost or delivery date is published, and identifying an option does not guarantee a connection date.
Flexible connections: No flexible-connection information for this area has been established.

Confidence: lowLast reviewed: 11 Sep 2026SSEN Distribution — Iver 132kV Grid Supply Point Strategic Development Plan, May 2025