Explainer - Nuclear Regulated Asset Base (RAB) Levy

The Nuclear Regulated Asset Base levy is a new charge linked to funding new nuclear power stations. The idea is that some project costs can be recovered while a station is being built, rather than only after it starts generating. The scheme is run by the Low Carbon Contracts Company.

The levy starts for the obligation period beginning 1 October 2025. It is being introduced in stages. For 1 October to 31 October 2025 the interim levy rate is set at £0.00 per MWh, with no reserve amount. For 1 November to 31 December 2025 the interim levy rate is £3.455 per MWh, and a separate reserve amount is also set for that phase.

There is also a small additional charge to cover the cost of running the scheme. This operational costs levy is currently £0.0028 per MWh and is collected in a similar way to the Contracts for Difference operational costs levy.

What this means in practice is that, once the scheme is active, suppliers and customers should allow for around £3.46 per MWh of nuclear RAB-related costs, before VAT and any other applicable charges. That is about 0.00346 £ per kWh, which is about 0.346 pence per kWh.

These amounts are expected to change over time. The Low Carbon Contracts Company will publish updated rates periodically, including quarterly updates to key values.