IN Brief:
- Ofgem proposes allowing demand, generation, and storage customers to build a wider range of assets dedicated to their transmission connections.
- Completed equipment would transfer to the relevant Transmission Owner rather than remain privately operated transmission infrastructure.
- Engineering assurance, adoption, cost allocation, and interfaces with the existing network remain central to the proposed framework.
Ofgem has proposed allowing demand, generation, and storage customers to build a wider range of transmission connection assets themselves before transferring the completed equipment to the relevant Transmission Owner.
The consultation forms part of Ofgem’s Connect programme and remains open until 13 November. It would expand the scope of self-build and transfer at transmission level, giving connecting customers greater choice over delivery of assets used only for their own connection between the project site and the existing transmission network.
Ownership would still pass to the Transmission Owner under the proposed model. A customer could appoint designers and contractors to deliver the connection, but the completed assets would have to satisfy the technical, safety, documentation, and adoption requirements needed for long term operation as part of the regulated network.
That boundary matters because changing who builds an asset does not change how the electricity system behaves. Cables, transformers, switchgear, protection relays, control equipment, communications, and civil infrastructure must still operate within the ratings and standards of the network to which they are connected.
Protection coordination is one of the interfaces that cannot be designed independently. A fault on the new connection changes current and voltage conditions seen by equipment on both sides of the boundary. Relay settings and circuit breaker duties therefore have to be developed with the Transmission Owner so faults are removed rapidly without disconnecting a larger part of the system than necessary.
Equipment ratings create another constraint. Conductors and transformers need sufficient thermal capacity for the expected demand or export, while switchgear must withstand and interrupt the fault levels that can occur at the connection point. Voltage performance, reactive power, earthing, insulation, environmental conditions, and future network changes also affect whether an asset can be adopted safely.
Ofgem’s proposal is intended to give customers more control over procurement and construction without transferring those technical risks to other users. The regulator says the framework must protect consumers from additional costs caused by the choice to use self-build and transfer rather than delivery by the incumbent Transmission Owner.
Construction quality therefore has consequences well beyond energisation. Cable joints, terminations, foundations, equipment installation, protection wiring, test records, and asset data need to support decades of operation. A defect that does not prevent initial energisation can still become a reliability or maintenance problem years later, when the Transmission Owner rather than the original contractor is responsible for the asset.
Adoption requires a complete engineering record as well as physical equipment. Drawings, test results, protection settings, equipment data, maintenance requirements, warranties, and evidence of compliance all need to pass across the ownership boundary. Without that information, the new owner can inherit plant it is expected to operate without an adequate record of how it was designed or commissioned.
Greater customer control could improve sequencing where the connection is closely tied to construction of a data centre, industrial site, battery, or generating project. A developer may be able to procure its own contractor and align electrical works with the rest of the site programme rather than wait for every element to be delivered through the Transmission Owner’s normal project pipeline.
That freedom does not guarantee an earlier connection date. A project can complete the assets dedicated to its own connection and still be unable to energise if the wider transmission network lacks sufficient capacity. Upstream substations, circuits, or reinforcement works may remain the limiting factor regardless of who builds the final connection.
The consultation develops a policy direction already reflected in recent grid reform measures. It also follows Ofgem’s rejection on 7 October of CMP330/374, earlier code changes intended to allow longer customer built connection assets and extend transmission contestability. Those modifications depended on CMP414 for the wider legal and operational framework, but NESO withdrew CMP414 in June.
Ofgem concluded that CMP330/374 could not provide a coherent or workable basis without that supporting framework. The new consultation therefore develops transmission build rights through a broader package that covers adoption, engineering assurance, ownership, and the relationship between the connecting customer and Transmission Owner rather than relying on the abandoned code changes alone.
The practical test will be whether the framework creates genuine delivery choice without weakening the standards applied to assets entering the regulated network. Customers may gain more control over design and construction, but the connection still has to survive faults, switching, maintenance, changing power flows, and future network development long after the original project team has left the site.
