Background to the report

Transmission networks move electricity over long distances from power generation sites to substations, where it is distributed to consumers through distribution networks. The National Energy System Operator (NESO) is responsible for the day-to-day operation of the electricity system in Great Britain. Ofgem regulates the transmission network operators that own and manage the networks in Great Britain.

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The Department for Energy Security & Net Zero (DESNZ) is working with Ofgem and NESO to upgrade the electricity transmission network to handle a higher capacity of renewable energy and to improve resilience, as part of its plan for Clean Power 2030.

Much of the current grid was built between the 1950s and 1970s, designed for large fossil fuel stations and is poorly matched to how electricity is produced today. The network now experiences constraints when the electricity system is unable to transmit power to electricity users because it has reached maximum capacity. NESO has identified over 80 transmission projects it considers are needed in order to meet demand and lower constraint costs.

Scope of the report

This report reviews the extent to which:

  • DESNZ, Ofgem and NESO are taking practical steps to support progress with delivering the upgrades
  • DESNZ, Ofgem and NESO have presented a robust value for money case for upgrading the transmission network
  • DESNZ’s approach to designing and setting up the programme to develop the transmission network is effective

Conclusion

DESNZ views upgrading the electricity transmission network as necessary to support Clean Power 2030, longer-term net zero objectives, and economic growth. Its case for action arises largely from the need for the grid to catch up with the growth in renewable generation and limit rising constraint costs borne by consumers.

Value for money now depends on delivery. Delivering all the grid upgrades by 2030 will be very challenging. There remain significant planning, supply chain and system access risks and some of the projects are already forecast for delivery after 2030. This means some new generation is likely to connect before necessary grid upgrades are complete. It is important to minimise this gap, as delays will increase project and constraint costs and postpone the benefit of achieving clean power.

DESNZ, Ofgem and NESO have taken steps to accelerate approvals, enable earlier investment, and join up their oversight. The upgrades represent a significant shift from historical regulatory approaches and will test systems not designed for delivery at this pace and scale.

Delivering upgrades at lowest cost to consumers will require stronger oversight of delivery, transparent monitoring of progress, and sufficient regulatory capability to scrutinise costs and the operation of incentives.

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View press release (11 Sep 2026)

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