Ember’s analysis was first included in a Labour press release about the party’s energy policies in March 2024 and the Department for Energy Security and Net Zero (DESNZ) has since confirmed the pledge was based on Ember’s forecast.
In its 2023 analysis, the think tank said UK households “could save £300 every year on their electricity bills in 2030 if the government completes its switch to a mostly clean power system by then”.
Ember said its baseline for measuring these savings was Ofgem’s price cap between July and September in 2023.
The analysis said savings from renewables would “far outweigh the total investment costs required”.
Czyzak told the BBC Labour’s pledge could still be achieved in a number of ways, including removing costs such as green levies from energy bills, or financing grid investments through rises in general taxation.
But when asked if the £300 savings estimate still stood, Czyzak said it was now “a much different situation than it was in 2023”.
He said the projected savings in his analysis were dependent on a significant drop in the wholesale cost of electricity in a scenario where renewables become cheaper and the dominant source of power in the UK.
“I think the question now will be whether the high cost of offshore wind doesn’t disrupt some of these wholesale energy savings,” Czyzak said.
He said if the cost of upgrading the electricity grid increased, and wholesale prices don’t go down as much, “then it’s going to be hard to generate savings”.
He added: “So then, yes, there is a risk of these savings being wiped out if we can’t get the actual electricity cost down, and that might happen if offshore wind is too expensive.”
Czyzak said Ember never suggested the £300 pledge was “the best solution to everything”.
“I think it’s generally quite a tricky one because of the volatility around everything. Everything in this market is very volatile. So if you’re just looking for a fixed single number, it’s not that easy to deliver,” he told the BBC.
While DESNZ has accepted market conditions have changed, it argues that new renewables are still cheaper to build than new gas-fired power plants.
A DESNZ spokesperson said lowering bills was “central to every decision we make and why we have already consented a record amount of clean energy”.
They added: “By making Britain a clean energy superpower we are getting the UK off the rollercoaster of fossil fuel prices and onto clean, homegrown power that we control.”