National Grid has published the RIIO-T3 business plan for its National Grid Electricity Transmission (NGET) business, covering the period from April 2026 to March 2031.

The plan includes an unprecedented level of investment of up to £35bn over the five years to March 2031, including a baseline investment of over £11bn to maintain and upgrade our existing networks, alongside construction works for the first three of our Accelerated Strategic Transmission Investment (ASTI) projects where project assessments have been approved and pipeline investment of around £24bn, which includes around £15bn to increase network capacity.

The investment is designed to deliver an innovative and reliable transmission network with “99.9999 per cent reliability levels”, upgrading and developing the network with the 17 ASTI projects and upgrade of c.3,500km of existing overhead lines, nearly doubling the amount of power we can transferred around the country.

The result should connect 35GW of new generation and storage, and 19GVA of large demand customers such as data centres and gigafactories, as well as creating a further 26GW of future connection options.

In addition to the obvious benefits of electrification, the investment will deliver a 50 per cent reduction in National Grid emissions versus a 2018/19 baseline, and biodiversity net gain equivalent to more than 8,000 acres of land, seven times the impact of RIIO-T2.

In line with Ofgem’s guidance, the plan aligns with the National Energy System Operator’s (NESO) Future Energy Scenario 2024 Holistic Transition pathway. The optionality in the plan also means it can be adapted to the UK government’s clean power plan. Whilst the specific investments required will be clarified through NESO’s connection reform process in 2025, the RIIO-T3 plan further underpins and is consistent with the expected £60bn investment across the group for the five years to March 2029.

Commenting on the final business plan, John Pettigrew, CEO of National Grid, said: "This plan represents the most significant step forward in the electricity network that we’ve seen in a generation. Through it we will nearly double the amount of energy that can be transported around the country, support the electrification of the industries of today and tomorrow; create new jobs; and support inward investment for the UK.”

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