Summary

  • The proposal covers project-only assets between a customer’s connection point and the existing transmission system; shared reinforcement remains outside it.
  • Self-build advances a connection only if the customer’s work controls the date. Ofgem’s savings estimates are scenarios, not guarantees.

On 7 October, Ofgem opened a consultation on self-build and transfer for transmission connections and rejected CMP330/374, an older code proposal for longer customer-built connections. The decisions change the regulatory route; they do not put a new rule into force. Ofgem said CMP330/374 depended on the wider legal and operational framework in CMP414. NESO withdrew CMP414 in June, so the Authority found the remaining package incoherent and unworkable. The new consultation proposes changes to licence conditions, the CUSC and the STC using powers under the Planning and Infrastructure Act 2025. Responses are due 13 November.

Demand, generation and storage customers could build assets used solely by their project, from its connection point to the existing transmission system, then transfer them to the Transmission Owner (TO). Ofgem gives overhead lines and project substations as examples. The asset must remain sole-use when the Adoption Agreement is signed. Wider enabling works and shared-network reinforcement are excluded because they serve the system more broadly and can be complex and costly.

That limit narrows what faster connections can mean. Stakeholders have cited savings around 20% and one to two years in some cases, particularly when no reinforcement is required. Ofgem cautions that a customer can finish its own assets sooner and still wait if shared works determine the connection date. Phased, ramped or non-firm arrangements can alter sequencing, but do not guarantee earlier energisation. Ofgem’s impact scenarios estimate £25m–£64m in possible customer savings; these are modelled possibilities, not commitments.

The customer also takes delivery risk. The proposed process includes an Adoption Agreement, engineering review through PASE, construction and commissioning, TO inspection and adoption, and a five-year defect-notification period. Customers initially bear consent and build risks; a failure to meet adoption conditions could strand spending. Technical approval remains with the TO. The consultation distinguishes customer connection assets from infrastructure that others may use, with separate proposed value-for-money and payment arrangements. It describes a proposal, not evidence that any project has used the route or connected earlier.

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