Vanguard’s £12 billion offshore wind deal revives a warning MPs heard in October. Both wind farms are due in 2030. The full Norwich to Tilbury reinforcement has a licence delivery date of 31 December 2031.
Parliament heard the warning in October
When Rupert Lowe MP asked which essential grid works were running late, Emily Bourne, the Government’s director for electricity systems and networks, named both sections of Norwich to Tilbury and the Sea Link cable between Suffolk and Kent. She told the Public Accounts Committee they were “always off track for 2030”. Lowe warned that getting the order of construction wrong would send constraint payments “through the roof”. (Committee transcript, Q15 and Q20)
We covered that warning in October. Twenty days after the hearing, as Andy Burnham prepared to head to COP31, Downing Street hailed RWE and KKR’s £12 billion investment in Vanguard West and East. Both projects had reached financial close, with a £1 billion financing commitment from the publicly owned National Wealth Fund. The Prime Minister said “a clean energy future is one that brings down bills”. (Our October coverage · Downing Street · RWE)
The wind farms are due first
RWE expects both projects to be fully commissioned in 2030. The Department for Energy Security and Net Zero confirmed the licence date for the full Norwich to Tilbury route to Parliament on 16 September. If the turbines are ready on RWE’s timetable and the line enters service at the end of 2031, both farms could operate for almost all of 2031 before the full reinforcement is available. Its first full calendar year in service would be 2032. (RWE timetable · Ofgem licence decision · Parliamentary answer)
The Norwich to Tilbury planning examination closed on 10 August. The inspectors’ recommendation was due on 10 November, with a decision on development consent to follow. The actual date the line will be energised remains unconfirmed. (Planning timetable)
The bottleneck beyond Necton
Vanguard’s 184 turbines will have about 2.8 GW of installed capacity. Their cables come ashore at Happisburgh and run to National Grid’s Necton substation. The electricity then shares the regional transmission network with other generators. When wind output exceeds what East Anglia can use locally and export, NESO can pay generators to turn down and buy replacement power elsewhere, often from gas plants. (Vanguard connection route · Installed capacity · NESO on balancing costs)
NESO put the cost in billions
When Clive Betts asked about the national cost, NESO chief executive Fintan Slye cited an estimate of £7 billion to £8 billion in 2030 from the operator’s 2024 advice. Slye said that estimate preceded measures to make better use of existing lines. He also told MPs that much of the cost comes from paying gas-fired stations to generate elsewhere. (Committee transcript, Q26 to Q33)
NESO’s modelling also estimated the additional 2030 costs to the electricity system if the East Anglia upgrades missed that year.
| Reinforcement unavailable in 2030 | Extra constraint costs |
|---|---|
| Norwich to Tilbury alone | £2.7bn to £2.8bn |
| Sea Link alone | £1.1bn to £1.4bn |
| Both reinforcements together | Around £4.2bn |
In the higher-renewables case, NESO estimated that about 23 TWh of East Anglian offshore wind would be unable to reach demand, with about 4 TWh of additional unabated gas generation needed. The Government’s own April 2026 pricing plan still cited roughly £4 billion of potential savings from bringing both reinforcements forward to 2030. (NESO networks annex · Government pricing plan)
Show billpayers the calculation
The £4.2 billion figure covers the two missing grid reinforcements in NESO’s 2030 model. The November announcements give no estimate of how much Vanguard’s own output could be turned down or what it could cost to manage the gap. RWE says each wind farm has a 20-year, inflation-linked Contract for Difference at £91.20 per MWh in 2024 prices. A bill forecast needs to account for those contracts, transmission investment and balancing costs alongside the value of the electricity delivered. (RWE financing announcement · Government announcement)
Ministers should publish how much of Vanguard’s output they expect the grid to carry in 2030 and 2031, how much NESO may have to turn down and what that means for bills. If they expect earlier works to ease the bottleneck, they should say which ones, when they will enter service and how much export capacity they will add.
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