THE Government move to review the new Hinkley Point nuclear power plant took people by surprise, but concerns over costs have been repeatedly raised.

Ministers in the coalition agreed three years ago that EDF would be paid £92.50 per megawatt hour (MWh) of electricity generated by the reactor for 35 years - or £89.50 per MWh if a new nuclear plant at Sizewell was also built.

In addition to the "strike price", a subsidy added to consumer bills, then chancellor George Osborne offered £2 billion in guarantees to sweeten the deal.

But Michael Grubb, professor of international energy and climate change policy at University College London (UCL), said the price of power from Hinkley Point had doubled from when the scheme was first mooted in around 2008.

At the same time, the cost of renewables has halved, with the Dutch government recently agreeing a price for power from an offshore wind farm significantly below that of Hinkley.

Just a few years ago, renewable electricity from wind, solar, hydropower and biomass accounted for just 6 per cent or 7 per cent of supply in the UK, but is now 25 per cent of the mix, an "astonishing achievement", he said.

As a result, he said: "We need flexible plants to make sure the lights go on, we don't need anything that will run flat out every hour of the year. The structure of what we need is going to be different.

"One big nuclear power station does not fit that structure that well."

And he warned that if nuclear was competing against other electricity sources with lower subsidies, such as wind farms, to meet a limited amount of demand, consumers would end up paying for the more expensive electricity from nuclear.

This is because the technology with the higher subsidies could sell its power at a lower price, while energy sources with lower subsidies would not be able to compete.

"It would be very irresponsible for a new minister to come in and not review a contract which could cost consumers £30 billion out to 2060 when so much has changed in the energy sector.

"I think it is entirely appropriate to pause and review," Professor Grubb said.

He said the UK may need nuclear power but "it's incredibly unlikely" Hinkley Point is the answer, and questioned how a large amount of nuclear power fitted with a system with renewables, increasing efficiency and a flexible demand control.

Dr Alastair Martin, founder of Flexitricity - which works with businesses and the public sector to provide "demand" responses such as using electricity when there are large wind supplies, said Hinkley's problem was it provided base load power.

There "isn't really such a thing" as base load any more, with the power system moving towards combined heat and power plants, small generators, active consumers who choose when to use electricity and more battery storage, he suggested

While he did not disagree with subsidies for energy infrastructure which "has a cost that needs to be recovered over a long period", he suggested the price was high and 35 years was a long time to be paying for the £18 billion nuclear plant.

"If you apply that to any other energy project you get an awful lot for your £18 billion. Think what we'd save if we spent it on energy efficiency," he added.

Ben Caldecott, associate fellow at Bright Blue, a liberal conservative think tank, said: "The Government should abandon Hinkley C - pursuing it in light of all the evidence of cost reductions in other technologies would be deeply irresponsible.

"We need a new 'Plan A'. This must be focused on bringing forward sufficient renewables, electricity storage, and energy efficiency to more than close any gap left in the late 2020s by Hinkley not proceeding."