TNEI on Grid – Connections Reform Timeline Published

Don’t risk losing out on your place in the connections queue, all evidence must be submitted before 29^th July 2025.

Last week (10^th June), NESO published the timeline for the delivery of connections reform in Britain. The timeline includes key dates for projects looking to progress to a Gate 2 offer as part of the Gate 2 to whole queue (G2TWQ) process, under CMP (Code Modification Proposal) 435: Application of Gate 2 Criteria to existing contracted background.

Figure 1: NESO Connections Reform Timeline

The key milestones TNEI has identified for projects passing through G2TWQ include:

• 20^th May 2025 – DNO Evidence Submission Opens. Small and medium embedded generators are now able to submit their evidence of meeting the Gate 2 requirements to their relevant DNO. Depending on the DNO evidence is either submitted via email using the NESO Readiness Declaration template or through an online portal.
• 8^th July 2025 – NESOs Evidence Portal Opens. Transmission and large embedded distribution connected projects will be able to submit evidence of meeting Gate 2 to NESO using the online portal, this will include the submission of an accompanying ModApp if the project wishes to be advanced or has a transitional connection agreement.
• 29^th July 2025 – Evidence Submission Window Closes. Both the NESO and DNO evidence submission windows will close on this date. All projects wishing to participate in the G2TWQ process must have submitted evidence of meeting Gate 2 to NESO or their DNO by this date.
• September 2025 – Offer Confirmation. Customers will be notified if their project has received a Gate 1 or Gate 2 offer. If the project is to receive a Gate 2 offer, it will be specified if this will be for a connection date in 2030 or earlier, or 2031-2035. Gate 1 and 2 offers will start being issued by NESO for transmission projects from the 15^th
• 31^st March 2026 – Transmission Gate 2 Offers. By this date all Gate 2 offers for transmission connected projects will be issued to customers who will have 90 days to accept.
• 15^th May 2026 – Distribution Gate 2 Offers. By this date all Gate 2 offers for distribution connected projects will be issued to customers who will have 90 days to accept.

In a recent webinar it was indicated that the dates provided towards the end of 2025 and 2026 are to be treated as expected ideals for the networks to aim for, opposed to firm dates to be stuck to.

TNEI’s Tips for a Successful Submission

• Take time to understand the format and content of evidence required. NESO has published the Evidence Submission Handbook to assist customers.
• Understand how to submit evidence to NESO or your DNO. Submissions to NESO should be via its online portal, whereas DNOs will be accepting submission via their own dedicated portals or by email (depending on the DNO).
• Submit as early as possible. NESO and the DNOs have stressed the importance of early submission to allow them to process the evidence and query any issues with customers where required. NESO will run initial checks for preventable errors. Customers which submit evidence in the first two weeks (8^th – 22^nd July) will receive feedback and will have 2 working days to respond if they fail initial checks, submissions in the final week will only have 1 working day.
• If you are requesting an advanced connection date, ensure that this is deliverable and that project milestones can be met. Engage with NESO/the relevant DNO if unsure.
• Keep in mind the ongoing need to meet Queue Management milestones following the receipt of a Gate 2 connection offer.

How Can TNEI Assist?

TNEI has extensive experience in the grid connection process and an in-depth understanding of the implemented reforms. Grid Connection support services that TNEI offer include:

• Support in preparing Gate 2 evidence submissions.
• Independent assessment against the Gate 2 Criteria, indicating the likelihood of projects meeting the readiness criteria and protection clauses.
• Clean Power 2030 Analysis providing an estimation of the amount of capacity in each transmission and distribution zone set out in the Clean Power 2030 Action Plan including indicative queue positions for each project.
• Pre-application services (eg. grid-led site finding, site and technology assessments, and feasibility studies in line with the ‘needed’ technologies specified in CP30).
• Connection application preparation and submission within the application windows, including ModApps.
• Techno-commercial Gate 1 and Gate 2 offer reviews, highlighting key risks, opportunities and next steps.

If you would like to know more about the reforms or how they will affect you, please contact gridconnections@tneigroup.com.