Factcheck: UK Conservatives double the ‘cost of net-zero’ after spreadsheet blunder

A booklet published ’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 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.