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Nuclear Regulated Asset Base (RAB) Levy

What is the Nuclear Regulated Asset Base (RAB) Levy?

The UK Government is working towards its 2050 net zero target, which includes reducing reliance on fossil fuels and transitioning to cleaner, low-carbon energy sources like nuclear power.

To support this shift, large-scale nuclear projects such as Sizewell C are being developed. However, these projects are expensive, take years to build, and often struggle to attract private investment due to the high upfront costs and long payback periods.

To address this, the Government has introduced the Nuclear RAB (Regulated Asset Base) Levy, a funding mechanism that helps attract investment by providing a stable, long-term revenue stream. It allows developers to recover costs during construction and earn a regulated return, reducing financial risk and lowering the overall cost of financing.

MHHS

The RAB model has been successfully used in the UK for major infrastructure projects like Heathrow Terminal 5 and in the water industry. It is regulated by Ofgem.

In the long run, this approach helps lower the cost of nuclear energy for consumers by avoiding the build-up of interest on loans. It also supports a more stable and secure energy system, less dependent on fossil fuels and volatile gas prices.

 

How do I get more information?

Further information on the model can be found at Future funding for nuclear plants - GOV.UK

Useful resources:

Additional Information

From 01 December 2025, a small government-mandated charge will be added to your unit rate(s) on each of your unit rates, including meters with multiple rates. This is not a charge introduced by us, we are simply passing on this cost in line with the legislation.

The levy is classified as a non-commodity cost and is made up of two new charges, which are mandatory for all suppliers and regulated by Ofgem.

All energy suppliers are required to contribute to this levy, with contributions based on their size and market share and include both domestic and non-domestic customers. Ofgem may also adjust the domestic price cap to reflect the RAB allowance.

For non-domestic customers, only Energy Intensive Industries (EIIs) will be exempt. All other non-domestic consumers will see this charge reflected in their bills.

This approach ensures transparency and consistency across the industry, while helping to fund the UK’s next generation of nuclear power stations.


The levy will take effect from 1 December 2025 and will be included in your unit rate(s) from that date.


The cost of the Nuclear RAB (Regulated Asset Base) levy is calculated through a regulated process. It includes three main components:

  • Interim Levy Rate (ILR):
    This is the primary charge applied to electricity bills to fund construction costs. It is set quarterly by the Low Carbon Contracts Company (LCCC) based on forecasted financial needs. For example, until 31 December 2025, the ILR is set at £3.540/MWh.
  • Operational Costs Levy (OCL):
    A smaller annual charge that covers the administration and running of the scheme. From 4 November 2025, the OCL is set at £0.0028/MWh.
  • Reserve Payments (TRA):
    These are contributions to a contingency fund that protects the scheme in case any suppliers default. Like the ILR, this is reviewed and forecasted quarterly by the LCCC.

The government’s Nuclear RAB Levy rate has been published at 00.3540p/kWh for December 2025 and has been forecast up to March 2027.

This rate excludes the Line Loss Factors (LLFs), which accounts for the unavoidable loss of electricity during its transfer to homes and businesses. The impact of LLFs has been considered in the overall calculation of the RAB charge.

To make things simpler, we have taken an average of both the Nuclear RAB Levy and LLFs over this period and combined them to determine a single flat rate of 00.46p/kWh that will be added onto your unit rate(s) for each of your meter points.

This approach means your charges remain consistent, even though the Nuclear RAB Levy and LLFs vary each month, making your monthly charges more predictable.

For example:

If your unit rate is 30.00p/kWh, it will increase to 30.46p/kWh.

Previous energy cost:
1000kWh × 30.00p/kWh = £300

New energy cost:

1,000kWh x 30.46p/kWh = £304.60

This would be an increase of £4.60.

The above example only illustrates changes to a unit rate and does not incorporate any additional charges such as VAT.

However, please be aware that this rate may be subject to change during your fixed term, as it is reviewed on a quarterly basis by the government.


If your meter point has multiple rates, such as Day and Night, the flat rate of 00.46p/kWh will be added to each one individually.

This means every unit of electricity you use, whether during the day or night will include the additional 00.46p/kWh.

For example: 

  • Current Day rate: 30.00p/kWh → New Day rate: 30.46p/kWh
  • Current Night rate: 15.00p/kWh → New Night rate: 15.46p/kWh

You use in a month:

  • 600 kWh during the day
  • 400 kWh during the night

Previous energy costs

  • Day: 600 × 30.00p/kWh = £180.00
  • Night: 400 ×15.00p/kWh= £60.00
  • Total: £240.00

New energy costs

  • Day: 600 × 30.46p/kWh = £182.76
  • Night: 400 × 15.46p/kWh = £61.84
  • Total: £244.60

This would be an increase of £4.60 in total.

The above example only illustrates changes to a unit rate and does not incorporate any additional charges such as VAT.


The rates published by LCCC are based on energy volumes that include network losses (energy lost during transmission). However, your business is billed based on meter-level volumes (the actual energy used at your site). To account for this difference, we are applying a small adjustment to the rates to cover these losses.

Our pricing also reflects forecasted costs over a longer period, not just the initial ILR for December. This helps provide a more stable and realistic view of expected charges over the duration of your tariff.


Non-commodity costs cover essential services that make sure energy reaches the destination reliably and efficiently. These include costs for transporting energy, maintaining the grid, and supporting government schemes for renewable energy and social initiatives. Without these, the energy system wouldn’t function.

Non-commodity costs may rise due to a variety of factors, including:

  • Investment in network infrastructure, such as upgrades to accommodate renewable energy sources.
  • Government policies encouraging renewable energy production and efficiency measures.
  • Increased balancing costs as the grid must handle a more complex mix of energy sources, such as intermittent renewable power (wind, solar).

Suppliers don’t have control over most non-commodity costs as they are set by regulators, network operators, and the government. These costs are passed on to consumers as they form part of the broader energy infrastructure that benefits everyone.


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