Britain will build new gas power stations to ensure it "keeps the lights on" as it moves towards net zero, the government said on Tuesday.
Claire Coutinho, the UK's Energy Security Secretary, warned of a "genuine prospect of blackouts" if the country cannot turn to gas when the weather shuts down wind and solar power.
She established election battle lines by attacking the opposition Labour Party's plans to phase out North Sea oil and gas production.
Rules are being drafted that would mean new plants must be "net-zero-ready", meaning they could be one day be retrofitted to use hydrogen or capture the carbon dioxide they emit by burning gas.
Critics say this is vague and warn Britain is heading backwards in the race for net zero, and that using gas leaves it vulnerable to global markets.
However, Ms Coutinho said backing investment in new gas plants does not conflict with Britain's international commitments to go green.
She pitched her policy as putting "national interest over narrow ideology" in a speech to the Chatham House think tank in London.
"Anybody who tells you that you can just stop oil and gas is not just wrong, but naive," she said.
"If countries are forced to choose between net zero and keeping citizens safe and warm, believe me: they’ll choose to keep the lights on. We will not let ourselves be put in that position. And so, as we continue to move towards clean energy, we must also be realistic."
Alan Whitehead, a Labour shadow energy minister, said Ms Coutinho's announcement raised "considerable question marks".
Labour could accept a minimal future use of gas as a "backup necessity" and if power plants are equipped to capture carbon, Mr Whitehead said.
But he added the government's talk of realism raises a "substantial red flag" that the term is being used to abandon "commitments that are absolutely necessary". The government last year pushed back deadlines for clean heating and electric cars after seizing on a backlash against low-emission traffic rules in London.
Ms Coutinho on Tuesday said Labour plans for the North Sea would increase the risk of power cuts and "leave a generation of oil and gas workers stranded".
The UK was among about 200 countries to commit at last year's Cop28 summit in the UAE to "transitioning away" from fossil fuels. The deal also outlines a role for "transitional fuels", widely taken as a reference to gas.
Officials argue that future supply cannot be forecast exactly and some of Britain's 32 gas plants are heading for retirement, meaning new builds are needed.
Ministers are also consulting on how to reform electricity pricing so that people feel the benefit when clean power is generated cheaply. This could include a move towards zonal pricing that reflects locally produced energy.
Myles Allen, a University of Oxford climate scientist, criticised the plan to merely require the option of carbon capture to be kept open in future.
Britain has "some of the best carbon storage capacity in the world and a nascent industry begging for a clear path forward", he said.
"We don't want to be just 'former climate champions' – some of us want the UK to be a future champion as well.”
A switch to electric-powered technology such as cars and heat pumps is expected to send power demand soaring in the coming years.
Electric cars could consume as much power by 2035 as would be produced by three nuclear power plants, according to one estimate.
Market reform would mean renewables are "able to meet more of our needs more often", said Dan Monzani of Aurora Energy Research.
"In a net zero system in 2035, we will need to run gas 90 per cent less often but we still need to maintain two thirds of the current gas capacity to ensure our energy needs are met at all times."
