Ofgem approves £642.1m Bramford to Twinstead grid upgrade

Overview

Updated Oct 20

Ofgem approved £642.1 million for a major electricity grid upgrade between Suffolk and Essex on 19 October 2026, cutting £60.6 million from National Grid's £702.7 million request. The Bramford to Twinstead project adds 18 km of overhead line and 11 km of underground cable to the 400 kV network in East Anglia, plus a new substation at Twinstead Green and upgrades at Bramford.

The funding still needs licence changes to take effect. Ofgem said it aims to consult on the proposed modifications to transmission operators' licences later this year. On the ground, National Grid has started underground cable work in Dedham Vale and is drilling ducts beneath the River Box, with that work scheduled to run into 2027.

Why it matters

The upgrade adds about £60 to household bills by 2031, but Ofgem estimates grid investment in this period saves £80.

Questions about this story

Free account needed to ask — your question is kept and asked for you right after sign-up. Answers are public.

No questions yet — be the first to ask.

Key Indicators

£642.1m

Approved funding

Ofgem approved this amount for the Bramford to Twinstead project, down from the £702.7m requested.

£60.6m

Cut from request

Ofgem trimmed this amount from National Grid's submitted costs.

£80

Estimated savings

Ofgem's estimate of savings from the transmission investment in its RIIO-3 package, compared with not investing in the grid.

18 km

New overhead line

New 400 kV overhead line between Bramford and Twinstead.

11 km

Underground cable

New 400 kV underground cable sections, including through Dedham Vale.

Voices

Curated perspectives — historical figures and your fellow readers.

Organizations Involved

Ofgem

Energy regulator

Approved £642.1m funding for the Bramford to Twinstead project

Britain's independent energy regulator for gas and electricity markets.

National Grid Electricity Transmission (NGET)

Transmission network owner and developer

Delivering the Bramford to Twinstead project, with cable work under way in Dedham Vale

Owns and operates the high-voltage electricity transmission network in England and Wales.

Balfour Beatty plc

Infrastructure contractor

Main works contractor for the Bramford to Twinstead project

UK-based infrastructure construction company.

Murphy

Construction contractor

Delivering the grid supply point substation

UK-based engineering and construction company.

Timeline

December 2022 October 2026

6 events Latest: October 19th, 2026 · 3 weeks ago

Tap a bar to jump to that date

October 2026
Ofgem approves £642.1m funding
Latest Regulatory

Ofgem approved £642.1 million for the project, cutting £60.6 million from National Grid's £702.7 million request.
October 19th, 2026
Main construction phase picks up in Dedham Vale
Construction

National Grid said it had begun 400 kV underground cable work in Dedham Vale, scheduled to run to June 2027, and started drilling ducts beneath the River Box in late September 2026. A road closure off Twinstead Road in Lamarsh was listed for 1 to 31 October 2026.
October 2026
2026
Wider construction work scheduled to begin
Construction

Further construction on overhead lines and underground cables was due to start in early 2026.
2026
September 2024
Government approves development consent
Approval

The Energy Secretary approved National Grid's application for the reinforcement.
September 2024
2024
Construction starts on Twinstead Green substation
Construction

Work began on the new substation at Twinstead Green, the first major construction milestone.
2024
December 2022
Ofgem includes Bramford to Twinstead in ASTI framework
Regulatory

Ofgem published its ASTI framework decision, including the project for fast-tracked assessment.
December 2022

Scenarios

Bramford to Twinstead completes on schedule, boosting offshore wind capacity

Likely Resolves by End of 2030

Discussed by: Ofgem and National Grid, which have both emphasized the project's role in connecting offshore wind by 2030

The project proceeds through construction without major delays, completing by 2030. This would allow the network to handle the additional offshore wind capacity the government targets, reducing bottlenecks and enabling more renewable energy to reach consumers.

Cost overruns trigger COAE adjustment for the project

Possible Resolves by End of 2028

Discussed by: Ofgem, which set the 5% COAE materiality threshold in its project assessment

Construction costs exceed the approved £642.1m by more than 5% (£32.1m), triggering the Cost and Output Adjusting Event mechanism. Ofgem would review and potentially adjust the funding allowance, adding to consumer bills.

Project delayed, missing the 2030 offshore wind target

Unlikely Resolves by End of 2029

Discussed by: Not currently predicted by named analysts; would require construction setbacks such as supply chain issues or planning challenges

Construction delays push the project's completion past 2030, potentially affecting the government's target of connecting 50GW of offshore wind. This could leave the network as a bottleneck for longer, restricting renewable energy flows.

Historical Context

One moment from history that rhymes with this story — and how it unfolded.

1960s

East Anglia 400kV network construction (1960s)

The 400 kV transmission network in East Anglia was built in the 1960s to supply regional demand centered around Norwich and Ipswich. The network was designed for the electricity needs of that era, not for transporting large amounts of offshore wind.

Then

The network served regional demand for decades.

Now

The network now acts as a bottleneck for renewable energy, as it can't handle the volume of offshore wind and other clean power being generated in the region.

Why this matters now

The Bramford to Twinstead project is a direct response to the 1960s network's limitations, reinforcing the corridor to handle modern energy flows.