The troubled Hinkley Point C nuclear power station will add £1bn annually to UK energy bills as soon as it’s switched on, official figures show.

The money will be taken from consumers and handed to the French owner EDF to subsidise operations, making it one of the UK’s most expensive sources of electricity.

A further £1bn will be added to bills by a separate nuclear levy, supporting construction of the Sizewell C nuclear power station in Suffolk, also led by EDF. Campaigners branded it a “nuclear tax on households”.

Details were revealed in documents released by the Treasury and the Office for Budget Responsibility in the wake of Rachel Reeves’s Budget.

They describe how EDF will be entitled to claim the money under the “Contracts for Difference” subsidy system as soon as Hinkley C begins operations, probably in 2030.

The documents state: “In 2030-31, Contracts for Difference (CfDs) are expected to generate £4.6bn in government receipts, including £1bn to fund subsidy payments to the Hinkley Point C nuclear power plant for its first year of expected generation.”

The impact on bills is linked to a 2013 agreement reached between EDF and Sir Ed Davey, the then energy secretary. He guaranteed that EDF could charge £92.50 per megawatt hour (MWh) of power once Hinkley Point C came online. With inflation, this equates to £133 today and is expected to reach about £150 in 2030.

If the wholesale cost of electricity remains at its current level of about £8/MWh, then EDF can claim an extra £70 from consumers and businesses via CfDs.

From January, energy bills will also be hit by an entirely separate levy designed to support the construction of another nuclear power station at Sizewell in Suffolk.

The Regulated Asset Base levy will add £10 a year to power bills from 2026, raising £700m, but will roughly double by 2030, when it will need to raise £1.4bn a year for Sizewell.

Official modelling suggests Sizewell C’s final costs could reach £100bn.

Bills could rise even further once approval is given for another nuclear site on Anglesey in north Wales, where the UK’s first small modular reactors are planned.

Alison Downes, of Stop Sizewell C, said nuclear power had proven to be among the most expensive ways of generating electricity.

She said: “The Government has a misguided belief that nuclear will be a cheap, ‘green’ solution to our energy needs, but the evidence shows the opposite – that costs of delivery and of dealing with nuclear waste – will continue to rise.

“We remain opposed to the imposition of a nuclear tax on households, given the acknowledged uncertainty about the projected costs of constructing Sizewell C.”

The surging cost of CfDs is part of a much broader increase in energy-related environmental levies. These add £14bn to energy bills at the moment, but this will rise to £19bn by the end of the decade, according to Treasury forecasts.

The CfD subsidy system, which also supports wind and solar, currently costs consumers and businesses £2.3bn a year, but those costs will hit £4.6bn by 2030-31.

Meanwhile, the Renewables Obligation, which funded the UK’s first wind farms, adds costs of £8bn a year.

The Capacity Market, which pays gas-fired power stations and hydroelectric facilities to be on standby in case wind and solar are hit by low wind and light levels, adds a further £1.6bn.

A government spokesman said the subsidies were necessary to unleash its planned “golden age of nuclear power”.

They said: “Hinkley Point C and Sizewell C will each deliver clean electricity for six million households for at least six decades. Sizewell C could save £2bn a year across the future low-carbon electricity system once operational, resulting in cheaper power for consumers.”

Hinkley C was initially forecast to cost £18bn, but spiralling construction costs have pushed the total bill to £46bn, equivalent to £700 per person in the UK.

EDF was contacted for comment.

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