Energy network companies have been allowed to increase funding to upgrade power and gas grids, despite the need to raise bills, under the RIIO-3 Final Determinations.

Most of the funding (£17.8bn) will go towards maintaining Britain’s gas networks, with the remaining initial investment (£10.3bn) for the electricity transmission network, improving reliability and expanding capacity to support electrification.

Together these commitments will rise to an estimated £90bn by 2031 across both gas and electricity networks.

Ofgem’s Final Determinations of the cost control period from 2026 to 2031, known as RIIO-3, considers the responses from electricity transmission owners, gas transmission and gas distribution companies following publication of Ofgem’s Draft Determinations in July 2025.

Domestically £108 will be added to bills by 2031: £48 for gas and £60 for electricity. Alongside maintaining grid resilience this investment could deliver savings of around £80 compared to not expanding the grid.

For energy-intensive businesses, the RIIO-3 investments could their bills by potentially 10 to 15 per cent, thanks to offsetting cost reductions from wholesale prices and Government’s supercharger mechanism.

Smaller business will see an increase in network charges. For example, by 2031, indicative network charge increases range from around £60 a year for a small holiday let or retail kiosk to £1,700 for small offices or hotels and £9,760 for a medium factory, reflecting differences in size and energy use.

Jonathan Brearley, Ofgem CEO, said: “The funding announced today will keep Britain’s energy network among the safest, most secure and resilient in the world. The investment will support the transition to new forms of energy and support new industrial customers to help drive economic growth and insulate us from volatile gas prices.”

Additionally, improved network capacity will enable faster connections for new industrial projects.

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