Sir Keir Starmer will use the Labour conference to appeal to voters who are “sick and tired” of soaring energy costs and angry at “12 years of failure” under the Conservatives.
The Labour leader announced plans to end dependence on fossil fuels, with all the country’s electricity generated by renewable and nuclear power by 2030.
Labour claims the plan would save UK households a total of £93 billion over the rest of the decade – or an average saving of £475 for each household every year.
The green energy revolution is being presented as an alternative path to growth after Friday’s mini-budget saw Liz Truss and Kwasi Kwarteng set out a massive package of tax cuts in the hope of reviving a sluggish economy.
Sir Keir used speeches to activists on the eve of the Labour conference opening in Liverpool to denounce the “shower” in Downing Street, who he accused of “taking the piss” by offering tax cuts to the rich while giving less support to poorer households.
The creation of a net zero carbon, self-sufficient electricity network would lead to permanently lower energy bills and independence from nations such as Russia, according to Labour.
The move could also create half a million jobs and make the UK the first country to have a zero-emission power system.
Sir Keir said: “The British people are sick and tired of rocketing energy bills and our energy system being exposed to dictators.
“They want long-term solutions to cut bills for good.”
In a speech to activists, Sir Keir said the Chancellor’s admission of Tory economic failure would be hung “around their necks” in the next election campaign.
He said: “There’s a change in the air. There’s an atmosphere, there’s a sense that Labour is ready to deliver.
“And don’t we need change after 12 years of this shower, 12 years of failure under this government, wages stagnant for 10 years, public services on their knees.”
It is already clear that the Chancellor’s mini-budget on Friday will set the dividing lines for the next general election, with Sir Keir telling Labour supporters: “I didn’t agree with almost anything he said in that financial statement yesterday apart from his opening sentence, when he said there’s a ‘vicious cycle of stagnation’.
“He’s right about that and it’s their vicious cycle of stagnation. That is the verdict on 12 years of Tory government, a vicious cycle of stagnation and we need to hang that around their necks.”
The former director of public prosecutions said it was good when “somebody who is caught red handed actually pleads guilty”.
He said the Government’s “driving ideology” is now to “make the rich richer and do nothing for working people”.
“If you earn a million pounds, yesterday, you got a £55,000 pounds tax cut, enough to pay for a nurse,” he said.
“It’s not trickle down, it’s taking the piss.”
But he insisted he would lead the “most pro-trade union Labour government you have ever seen”, promising a Green Paper on workplace rights within 100 days of an election victory.
The conference is vital for Sir Keir to present himself as an alternative prime minister to Ms Truss, with the next election expected in 2024.
Sharon Graham, general secretary of the Unite union, told the BBC the Labour leader should “be bolder” in his economic policy and not “stand still” in order to win power.
The conference will formally begin on Sunday, with tributes to the Queen and a rendition of the national anthem.
Sir Keir’s energy plan was welcomed by environmental group Greenpeace UK, whose head of politics Rebecca Newsom said: “The only way out of this mess is a moonshot mission to roll out a renewables-based energy system that can lower bills, cut emissions, create jobs and break our dependence on gas markets and fossil fuel autocrats.
“Labour seems to have understood that, the Conservatives don’t.”
Luke Murphy, associate director for energy and climate at the centre-left IPPR think tank said: “This is a welcome and bold commitment to expand clean power and renewables, and reduce our dependence on expensive and climate destroying fossil fuels.”