Grid Connection Reform: What It Means for Commercial Solar (2026)
Updated 23 October 2026 · SEO Dons Editorial
What is connections reform?
Connections reform is the rewrite of how generation and storage projects secure a place in Great Britain's grid queue. NESO says Ofgem approved it in April 2025. NGED sums up the principle as "first ready and needed, first connected".
Projects are sorted into two statuses. Gate 2 projects meet the readiness and strategic alignment requirements and, in NESO's words, "can secure a confirmed connection date, connection point, and queue position". Gate 1 projects do not meet them and receive no confirmed date. The one-off exercise that sorted the existing queue is Gate 2 to Whole Queue (G2TWQ). Future applications follow an enduring process that ENWL and NGED call CMP434.
Does connections reform apply to a commercial rooftop or small ground-mount?
Usually not outside Scotland. The reform applies to projects that need a Transmission Impact Assessment (TIA), and SP Electricity North West says it "does not cover embedded generation below the TIA threshold". SSEN describes the affected projects as those where a TIA "will need to be carried out". The threshold depends on where the project is.
| Area | TIA threshold stated | Where it is stated |
|---|---|---|
| England and Wales | 5MW, or 1MW where the Grid Supply Point has fault level issues | NESO (12 May 2025), NGED, SSEN |
| Mainland Scotland | 200kW | NESO (12 May 2025), SSEN |
| Scottish islands | 50kW | NESO (12 May 2025), SSEN |
NESO's notice of 12 May 2025 says the England and Wales threshold rose from 1MW to 5MW "where fault level issues aren't present", taking effect that day. Not every page has caught up. ENWL's explainer still calls the threshold "currently 1MW", and ENA's connections data page tracks reform data at 1MVA/1MW and above. Treat any single page as a pointer and ask the network operator to confirm the figure in writing.
For example, a 400 kW array on a warehouse roof in England sits far below the 5MW line. The same array on a mainland Scottish site sits above the 200kW line, so it would need a TIA and the gate process would apply. That is an illustration of the thresholds, not advice on a specific site.
What has happened to the queue, and when?
ENA says NESO supplied final queue information on 4 December 2025 and that network operators began issuing customer notifications on 8 December. ENWL stresses those notices were "not formal offers / variations". NESO's Gate 1 page adds that a Gate 1 outcome keeps a project in the process but does not reserve capacity or a place in the queue, so the project must apply again in a future window.
Offers are being issued in phases. NESO's timeline update of 13 February 2026 (text revised on 17 April 2026) set these windows for distribution offers:
| Offer group | Window NESO gave |
|---|---|
| Protected distribution offers (Clause 1 or Clause 2a protections) | Early March 2026 to end May 2026 |
| Gate 2 Phase 1 distribution offers | Early July 2026 to mid-November 2026 |
| Gate 2 Phase 2 distribution offers | Mid-October 2026 to mid-March 2027 |
NGED defines Phase 1 as projects needed by 2030 and Phase 2 as projects needed by 2035. NESO reported on 19 August 2026 that offers had gone to more than 60% of the projects needed for 2030, and on 1 October 2026 that more than 75% of the offers needed to support the 2030 energy system had been issued. NGED's offers page, last updated on 23 July 2026, said it was preparing Phase 1 variation offers in batches. The timeline has been revised before, so read NESO's current page rather than relying on this table.
What counts as ready for a project that is in scope?
NESO says developers "must demonstrate both readiness and alignment with one or more strategic criteria". NGED explains that a project can sit in Gate 1 because it has not provided evidence that it meets land requirements, or because it is not strategically aligned to Clean Power 2030. SSEN's summary of the evidence route lists land rights as a three-year option with a lease, existing ownership of the site or an existing lease, plus a red line boundary showing location, installed capacity and minimum acreage.
That list is written for sites with a defined area, so a roof-based project should ask the network operator what it accepts as evidence of control. For small and medium embedded schemes, ENWL says the transmission assessment starts after the distribution offer is accepted, and the network operator can only pass the scheme to NESO "within the next available Window". ENA also lists a document titled DNO Queue Entry Requirements for Generation Schemes, dated 18 December 2024. Its detail is in that document and is not summarised here.
What is still proposed or undated?
- The next application window. NGED says it is working with NESO and others "to confirm when the first CMP434 window will open", that customers cannot submit evidence outside windows, and that later windows will open twice a year. No opening date appeared on the pages checked.
- Methodology updates. NESO's design documents page says the updated methodologies from its June 2026 consultation "have now been submitted to Ofgem for final review". Until Ofgem decides, treat those changes as proposed.
What can a small site do instead?
A project below the threshold sits outside the gates, so its limits are those of the local network. A sensible order of work:
- Find the operator with ENA's postcode finder, then ask in writing whether a TIA applies and which threshold the operator uses.
- Screen the site on the operator's capacity map, as set out in the DNO heat map guide.
- Ask whether an export limit is acceptable. The export limitation guide explains how G100 schemes work.
- Ask about flexible connection types. ENWL lists system normal, export limited, import limited, timed and active network management connections, and says of the export limited type: "You can install more generation than you're allowed to export, but your export to the network is capped at an agreed level."
- If an offer relies on active network management, ask for the curtailment estimate. NGED says its estimator depends on "the queue ahead in the Last In First Out (LIFO) stack", which ties a flexible offer to the queue.
NGED's explainer says battery storage is "substantially oversubscribed" and solar "slightly oversubscribed" across its area, so local capacity is worth checking early. The full specification, including the grid step, is set out in the commercial PV systems guide. A competent contractor checks these points before sizing the array, and you can send site details through the site's enquiry form.
Sources
- NESO, About Connections Reform, checked 22 October 2026.
- NESO, Connections reform timeline (update of 13 February 2026, text revised 17 April 2026), checked 22 October 2026.
- NESO, Gate 1 information, checked 22 October 2026.
- NESO, Streamlining the connection of projects under 5MW (12 May 2025), checked 22 October 2026.
- NESO, Connecting to the grid has to work for investment, not hold it back (19 August 2026), checked 22 October 2026.
- NESO, What industry needs next from connections reform (1 October 2026), checked 22 October 2026.
- NESO, Connections Reform design documents and methodologies, checked 22 October 2026.
- National Grid Electricity Distribution, Understanding Connections Reform, Offers, pipeline and application windows (last updated 23 July 2026) and Curtailment Analysis, checked 22 October 2026.
- SSEN Distribution, Connections reform: what's next for SSEN Distribution customers, checked 22 October 2026.
- SP Electricity North West, What is connections reform and why is it needed, Gate 2 To Whole Queue and Flexible connections, checked 22 October 2026.
- Energy Networks Association, Connections reform, Connections data, DNO Queue Entry Requirements for Generation Schemes and Who's my network operator?, checked 22 October 2026.
Common questions
Do I need a Transmission Impact Assessment for a 100 kW roof?
Not in England or Wales on the thresholds NESO, NGED and SSEN publish, which are 5MW or 1MW where the Grid Supply Point has fault level issues. Mainland Scotland uses 200kW and the Scottish islands 50kW. The network operator confirms the position for a given site.
Is a Gate 1 result a refusal to connect?
No. NESO says a Gate 1 notification means the project can remain in the connections process, although it does not reserve capacity or a place in the queue. The project must apply for Gate 2 in a future window and meet the evidence requirements.
How do I find out which network operator covers my site?
ENA runs a postcode lookup called Who's my network operator. The operator maintains the wires and is separate from the energy supplier. ENA's connections reform page then lists how to contact each operator about the programme.
Who runs the reform?
NESO leads it with the transmission owners and distribution network operators, and Ofgem approved the package in April 2025. ENA says network operators are engaging with small and medium embedded projects in line with NESO's timeline.