Government advisers have told ministers to back only a single new nuclear power station after Hinkley Point C in the next few years, because renewable energy sources could prove a safer investment.

The National Infrastructure Commission (NIC) said the government should cool down plans for a nuclear new build programme that envisage as many as six plants being built.

The commission, launched by George Osborne in 2015, said that a decade ago it would have been unthinkable that renewables could be affordable and play a major role in electricity generation. But the sector had undergone a “quiet revolution” as costs fell, it said.

Sir John Armitt, the NIC’s chairman, said: “They [the government] say full speed. We’re suggesting it’s not necessary to rush ahead with nuclear. Because during the next 10 years we should get a lot more certainty about just how far we can rely on renewables.”

He argued that wind and solar could deliver the same generating capacity as nuclear for the same price, and would be a better choice because there was less risk. “One thing we’ve all learnt is these big nuclear programmes can be pretty challenging, quite risky – they will be to some degree on the government’s balance sheet,” he said.

“I don’t think anybody’s pretending you can take forward a new nuclear power station without some form of government underwriting or support. Whereas the amount required to subsidise renewables is continually coming down.”

Renewables were a “golden opportunity” to make the UK greener and make energy affordable, he added.

Armitt said he was agnostic about whether the next power station was the one Hitachi wanted to build in Wales, or one EDF Energy hoped to build in Suffolk. The government is in the process of negotiating a deal with Hitachi to enable the project at Wylfa on Anglesey to go ahead.

But the NIC’s report was unequivocal. It said: “Government should not agree support for more than one nuclear power station beyond Hinkley Point C before 2025.”

Armitt said: “By that point we should be in better position on storage technology and presumably [will] continue to see a drop in price on renewables.”

The NIC said that by 2030 a minimum of 50% of power should come from renewables, up from about 30% today.

New figures released by energy analytics firm EnAppSys show renewables have already overtaken nuclear for electricity generation. Wind, solar and biomass power stations supplied 28.1% of power across April, May and June, with nuclear at 22.5%, the third quarter in a row that renewables have outstripped nuclear.

The government has repeatedly stressed its backing for new nuclear plants, recently striking a sector deal with the nuclear industry.

A government spokesperson said: “As we continue our transition to a low-carbon economy and meet this challenge the government is committed to providing a secure energy system with a diverse energy mix in which new nuclear has an important role to play.”

But Armitt said he was hopeful that, as an independent adviser to ministers, his recommendations would fall on receptive ears. “We’ve seen how long it took to negotiate Hinkley – does the government really want to have to keep going through those sort of negotiations?” he said.

Separate research commissioned by the NIC and published on Tuesday found that nuclear and renewables could meet climate targets for comparable costs.

Aurora Energy Research concluded that, regardless of which technology was pursued, the power sector would have to reach zero emissions by 2050 to hit legally binding carbon goals.

In a statement, EDF Energy said it believed “in having as much renewable power as practically possible and is making major investments in renewables. However, having too much of one energy type creates risks to security of supply and increases costs.”