A booklet published by the UK’s opposition Conservative party includes a “cost of net-zero” that appears to have been doubled by a spreadsheet error.
The “common sense” policy document argues that “what people ultimately want is a government competent enough to solve the problems for which it takes responsibility”.
In a section that says “sophisticat[ed]…modelling” should not be a substitute for “political judgement”, the “Right Way” document disparages various estimates of the cost of net-zero.
The Conservative document then claims – incorrectly – that the government’s official adviser, the Climate Change Committee (CCC), had put the cost of net-zero at close to £1tn. It says:
“In 2020, the CCC estimated that its route to net-zero would cost £957bn.”
In fact, the CCC’s 2020 estimate was exactly half this amount – £478bn – and last year it published a revised figure of £108bn, largely as a result of the falling cost of electric vehicles (EVs).
Spreadsheet error
The Conservative party’s erroneous claim appears to stem from another report that had accidentally added up numbers twice, using a spreadsheet published by the CCC in 2020.
The 2020 spreadsheet contains a table listing the additional investments that would be needed to build a net-zero economy, from low-carbon electricity generation through to heat pumps and EVs.
These extra capital expenditures, listed as “CAPEX”, add up to a total of £1.38tn over the 30 years of 2020-50. They are set against operational savings, listed as “OPEX”, of £0.90tn.
Added up over 2020-50, the combined CAPEX and OPEX figures come to a total of £478bn.
In addition to the annual sectoral CAPEX and OPEX figures, the CCC’s 2020 spreadsheet also has a line giving combined totals for each year. It appears that someone has added all of these numbers together, resulting in the savings and costs being counted twice.
This double-counted total for the cost of net-zero amounts to £957bn – as shown in the image below – and it appears to be the source of the claim in the Conservative booklet.
At the time of publication in 2020, the CCC said that the £478bn net cost of net-zero amounted to less than 1% of GDP over 30 years – and that the large investment needed would not only result in savings due to lower fossil-fuel imports, but that it would boost GDP overall, by around 2%.
In 2025, the CCC revised its estimates for investment costs and operating savings to £670bn and £562bn respectively, giving a net total of £108bn over 2025-50, or less than 0.2% of GDP.
Earlier this year, the committee said that cutting emissions to net-zero would cost less than a single fossil-fuel price shock and that doing so would have benefits worth £110bn per year.
Paper trail
The erroneous claim in the Conservative document is referenced to the CCC’s 2020 advice on the UK’s sixth “carbon budget”, which, as explained, does not contain the £957bn figure.
The earliest online use of the £957bn figure found by Carbon Brief is a 12 January 2026 article in the Spectator, by retired engineer and self-described “accidental energy analyst” David Turver.
A day later, Turver repeated the mistaken number in a report for the free-market Institute of Economic Affairs. His report cites figure 5.3 of the CCC’s 2020 advice.
However, as set out above, the CCC spreadsheet containing the data for figure 5.3 only adds up to £478bn, half the figure claimed by Turver.
It appears that Turver accidentally added up all of the numbers in the CCC spreadsheet, without noting that it already included a line for the annual total. This results in double-counting the cost.
(Turver’s report also triggered a slew of inaccurate headlines stating that net-zero would cost £7.6tn – or even £9tn. These figures, which came from Turver’s report, were based, among other things, on the implicit assumption that fossil fuels and the cars, boilers and power plants that use them are all free.)
After Turver’s report and article in January 2026, the erroneous £957bn figure was repeated in March by the Great British Think Tank. The organisation has the tagline “data, not vibes” and says of its work: “Every figure [is] sourced from official public bodies.”
The £957bn figure then appeared in the Conservative “Right Way” document in October 2026.
Analysis: EVs are now nine times cheaper than petrol or diesel to drive in the UK
CCC: Heathrow expansion could push flights to ‘80% of UK emissions by 2050’
Revealed: England’s June 2026 heatwave sparked record demand for ambulances
Discussion about this post