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Great British Energy -Nuclear (GBE-N) reveals £20bn SMR TP Contract forecast breakdown after saying it didn’t have budget details

Tom Pashby, Sep 03, 2026, https://tompashby.substack.com/p/gbe-n-reveals-20bn-smr-tp-contract?utm_source=post-email-title&publication_id=6735486&post_id=213980624&utm_campaign=email-post-title&isFreemail=true&r=ln98x&triedRedirect=true&utm_medium=email

Great British Energy – Nuclear (GBE-N) has admitted it does have a breakdown of the forecast £20bn initial estimate for its small modular reactor (SMR) technical partner contract (TP Contract), despite having previously said it didn’t have details of the budget.

GBE-N is the UK Government’s body responsible for building the UK’s first government-supported SMRs. Rolls-Royce SMR has been selected by GBE-N to built three of its SMRs at the Wylfa nuclear site in North Wales.

In May, GBE-N announced it had awarded Rolls-Royce SMR stage 1 of the SMR TP Contract. It said: “The forecast Stage 1 price of the TP Contract is £359,000,000. This forecast price may change.

“The forecast Stage 2 price of the TP Contract is approximately £8,168,000,000. This forecast price is indicative only as the pricing mechanism for Stage 2 remains subject to negotiation during Stage 1.”

Taken together, that placed the forecast cost of the total TP Contract at £8,527,000,000. It is worth noting that the TP Contract does not capture the full cost of GBE-N’s Wylfa SMR project.

The contract award announcement also said: “The estimated total value within the tender notice for the two-stage TP Contract was £20,000,000,000 excluding VAT. This value was indicative only and based upon GBE-N’s initial understanding of the potential costs of developing a first of a kind technology.

“This estimated total value was based on the fact that in the tender notice GBE-N reserved the right to make up to four awards, although GBE-N also reserved the right to award three, two or only one contract(s). GBE-N has ultimately decided to award only one TP Contract and the contract award notice value reflects this.”

Given that the notes say GBE-N had an initial estimated £20bn for the TP Contract, and that it reserved the right to make up to four awards, it could reasonably be assumed that it had estimated each contract would have a value of £5bn. However, this was unclear.

Via the Freedom of Information (FOI) Act, GBE-N was asked to provide a breakdown of the £20bn figure.

In response, New Civil Engineer revealed that GBE-N said: “Following reasonable and proportionate searches of our records, we confirm that Great British Energy – Nuclear (GBE-N) does not hold the information you have requested.”

20 Working Days challenged this response via a request for an internal review and GBE-N chief financial officer Neil Cooper responded to say that upon further inspection, the organisation did have a breakdown of the figure.

“In our original decision, we concluded that GBE-N does not hold the information requested,” Cooper said.

He went on to say that, following the internal review, GBE-N concluded that it “does hold information within the scope of your request.

“Our review has found that our original decision did not identify this information because it sits within a document whose predominant purpose is not to explain the calculation of the £20bn figure and which was therefore not considered to fall within the scope of your request.

“We consider it was reasonable to have concluded initially that the document did not contain information within the scope of your request. On further review, however, we are satisfied that it does, and we have therefore continued to assess whether the information we hold is disclosable under the EIR (Environmental Information Regulations).”

However, he added: “Our review has concluded that the information held by GBE-N should be withheld from disclosure under the exceptions in Regulation 12(5)(e) (Confidentiality of commercial or industrial information) and Regulation 12(5)(b) (The course of justice and inquiries) of the EIR.”

He went on to explain this further, saying: “We are withholding the requested information in reliance on Regulation 12(5)(e) of the EIR, which permits a public authority to refuse to disclose information to the extent that disclosure would adversely affect the confidentiality of commercial or industrial information where such confidentiality is provided by law to protect a legitimate economic interest.

“The information you have requested includes inter alia vendor cost estimates, government funding assumptions, the approach to negotiation strategies, and assessments of vendor capability relating to the Small Modular Reactor Technology Selection Process.

“Much of this information was obtained through confidential market engagement, and the information is identified as being market-sensitive.”

Cooper did find that he was able to provide an explanation for the £20bn figure without releasing internal documents.

“Although we have concluded that the information that you have requested is exempt from disclosure, we have set out below an explanation of how the £20bn figure was derived,” he said.

“The £20bn estimated total value in the Contract Notice of 2023 was an indicative, best-estimate at the time figure, published to meet the legal requirement to state the total potential value of the contract award including all options on the number of sites and technology providers.

“It was arrived at on an objective basis reflecting GBE-N’s understanding at the time, and anticipating a procurement capable of supporting up to two small modular reactor projects (broadly £10bn per project), across the whole life of a project, from early development through to commercial operation.”

It is unclear whether a single SMR ‘project’ would cover the three Rolls-Royce SMRs which are proposed for the Wylfa site, or whether that would mean a single reactor.

Cooper continued: “Because the technology is first-of-a-kind and yet to be developed, the estimate necessarily carried significant uncertainty, as the Contract Notice made clear.

“The detailed assumptions underpinning the figure comprise commercially sensitive vendor cost information and funding and negotiating assumptions obtained through confidential market engagement, and to the extent that they fall within the scope of your request these are withheld under regulation 12(5)(e) of the EIR for the reasons set out in this response.”

GBE-N was approached for comment.

September 6, 2026 - Posted by Christina Macpherson | business and costs, Small Modular Nuclear Reactors, UK