Ed Miliband has been accused of using “guesswork” over Labour’s pledge to cut energy bills by 2030.
The party said £300 would be taken off the cost of gas and electricity during the general election campaign.
Miliband, the energy secretary, today unveiled reforms which will make it easier for onshore wind farm projects to get the go-ahead as the government tries to make the electricity grid carbon-free by the end of the decade.
On Radio 4′s Today programme this morning, presenter Nick Robinson told the minister: “You made a big promise - £300 you say household bills will go down. Are you guaranteeing that those lower bills will be felt by people before the next election?”
Miliband replied: “What we said at the election, and it was based on independent modelling, was that bills would be up to £300 lower by 2030 in a clean power system, and we stand by the view that this will lower bills.
“Don’t take my word for it. The national energy system operator said that not only was clean power achievable, but it will lead to lower costs of electricity and indeed it can leads to lower bills.”
But Robinson hit back: “I’m puzzled by this, Mr Miliband. You’re quoting this independent national energy system operator. Let me quote them: ‘Overall costs to consumers would not increase from the shift to a clean power system’.
“When they were asked in the House of Commons whether they were saying that prices would come down, ‘that’s not what we set out to do’, said the man in charge, ‘that’s not our role, to determine what bills are for consumers’.
“They’re not saying that there’s a guarantee of any sort that bills will come down, are they?”
Miliband said: “They’re not saying it’s a guarantee. What they are saying is it will lead to lower wholesale costs of electricity ... and it can lead to lower bills.”
Robinson then asked him: “Can, may, perhaps. It’s all based on one scenario about what gas prices will be. But you don’t have any control over gas prices and neither do they. This is guesswork, isn’t it?”
Miliband replied: “No it isn’t, and let me explain why. What we are doing is laying the foundations for an energy system that will lead to lower bills because the costs of running a system which is largely based on renewables is significantly cheaper than running one based on gas.”
Miliband was also grilled about Labour’s pledge while appearing on LBC with Nick Ferrari.
The presenter asked: “Are you ready to hang your hat and your hi-vis vest on that figure of £300, Mr Miliband?”
He said: “I’m repeating what we said in the election, which is that bills will be up to £300 lower.”
Ferrari replied: “Up to?”
Miliband said: “Yes, that’s what the independent modelling said, that’s what we’re saying.”