Ed Miliband set Labour back a decade when he not only failed to win the 2015 general election but went backwards, losing a net 26 seats and helping to usher in the disastrous era of Jeremy Corbyn. But could he now be about to undermine a Keir Starmer government too?

Miliband has a little fantasy that he is trying to sell the public: that net zero targets won’t just save the planet, they will cut our energy bills, too. ‘Families across the country are united in their desire for lower bills, cleaner water, and a green and pleasant home that we can leave our children,’ he is to tell the Green Alliance in a speech today.

Rishi Sunak, he claims, is condemning us all to higher bills by watering down net zero targets. All, apparently, out of a desire on Sunak’s part to ‘stoke the fires of a culture war’.

Miliband’s promise to decarbonise electricity by 2030 and save us money in the process is doomed

Miliband’s calculation is that there are substantial numbers of Tory voters who are offended by Rishi Sunak’s minor retreat on net zero and who might be willing to lend their vote to the Labour party instead.

The trouble is that the number of people who share Miliband’s fantasy – that net zero will save us money – is fast diminishing. On the contrary, even those who are very much in favour of net zero targets are increasingly warning about the costs – and that message is rapidly sinking into the population at large. For example, Olivier Blanchard, former chief economist of the IMF, told the House of Lords Economic Affairs Committee last month that there will be a ‘substantial fiscal cost to net zero… The public do not believe, or has not been made to understand, that it is going to be costly for them. It is going to be costly and the message has to be set out.’

As Dieter Helm, professor of energy policy at Oxford university – who is certainly not advocating the abandonment of net zero policies – has warned, Miliband is trying to sell a narrative based on interest rates which were at near-zero in actual terms and negative in real terms. The return of interest rates to more normal levels has hugely increased the cost of the investment which will be needed to get anywhere near net zero – a cost which will be added to consumers’ bills.

Not only that, National Grid is warning that Miliband’s plan to decarbonise the grid is not achievable by his target year of 2030 at any price – and the company is already spending £58 billion trying to reconfigure the grid for the government’s own decarbonisation target of 2035.

Miliband has failed to explain how his plan will deal with the problem of intermittency of wind and solar. How will he keep the lights on if gas power plants – which are currently used to balance the supply of unreliable renewables – have to be closed down in just six years’ time? The possible solutions – such as battery storage, hydrogen storage or continuing to use gas plants fitted with carbon capture and storage – are all either fantastically expensive or don’t even exist yet at scale in Britain.

Moreover, there is another black cloud on the horizon. The trade body Energy UK is warning that the EU’s Carbon Border Adjustment Mechanism, which seeks to tax imports according to their carbon intensity, threatens to make energy exports from the UK to the EU via undersea cables uncompetitive because it assumes an incorrectly high carbon content for UK electricity.

It is yet one more EU protectionist policy dressed up in green clothes, but one which threatens to undermine the economic case for more North Sea wind farms.

Miliband’s promise to decarbonise electricity by 2030 and save us money in the process is doomed from the beginning. It is a failure that voters are unlikely to forgive if they see bills surging as a result of net zero policies in the next parliament.