Energy price cap methodology: Nuclear Regulated Asset Base (RAB)

Details of outcome

We have decided to include an allowance for costs associated with the Nuclear RAB in the default tariff cap from 1 January 2026.

Our decision document considers responses received to the consultation and sets out the methodology for calculating the allowance. 

The decision will ensure that default customers pay no more than the efficient costs incurred by suppliers in funding the Nuclear RAB scheme.

Read the full outcome

Note: the document attached below, Annex 4 - policy cost allowance methodology v1.22, is not fully accessible. If you require an alternative format, please contact retailpriceregulation@ofgem.gov.uk. 

Original consultation

Consultation description

We are consulting on our proposed methodology to account for the costs associated with the Nuclear RAB into the default tariff cap. The Nuclear RAB is a finance model that was introduced to fund new nuclear power projects under the Nuclear Energy (Financing) Act 2022.

We intend for the outcome of this consultation to be in place from January 2026 onwards.

Who should respond

We would like views from people with an interest in the default tariff cap levels and future electricity generation in the price cap. We particularly welcome responses from:

• energy suppliers
• other interested industry parties
• consumer groups
• charities
• the public