Ofgem RIIO-3 £90bn network plan: design and risk notes for civil engineers
Reviewed by Joe Ashwell

First reported on New Civil Engineer
30 Second Briefing
Ofgem has confirmed final determinations for the RIIO-3 price control, enabling up to £90bn of regulated investment in Britain’s gas and electricity transmission and distribution networks between April 2026 and March 2031. The framework sets allowed revenues and performance incentives for National Grid Electricity Transmission, gas transmission operators and the regional distribution network operators, targeting large-scale grid reinforcement, new 400kV and 275kV capacity, and resilience upgrades. Civil and geotechnical works will centre on substation expansions, cable route corridors and asset hardening to accommodate rapid electrification and higher renewable penetration.
Technical Brief
- For civil and geotechnical consultants, determinations signal a sustained pipeline of grid-related construction work.
Our Take
Within the 142 Infrastructure stories in our database, Britain’s regulatory pieces involving Ofgem are relatively few, so a £90bn-scale determination for the 2026–2031 period is likely to be a key reference point for future UK grid and interconnector project economics.
Locking in a five-year window from April 2026 to March 2031 gives UK transmission and distribution operators clearer revenue visibility than many project-led items in our Projects/Sustainability set, which should make it easier to finance large reinforcement and resilience schemes tied to net-zero targets.
For civil contractors and consultants focused on the United Kingdom, a defined 2026–2031 regulatory horizon typically translates into a multi-year pipeline of substation builds, overhead line upgrades and undergrounding works, rather than a single mega-project, spreading workload but also intensifying competition for skilled labour and consenting capacity.
Prepared by collating external sources, AI-assisted tools, and Geomechanics.io’s proprietary mining database, then reviewed for technical accuracy & edited by our geotechnical team.
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