Conservative Party Net-Zero Policy Document Cites Figure Doubled by Spreadsheet Error

A recent policy booklet published by the UK’s opposition Conservative Party features a prominent financial figure regarding the "cost of net-zero" that appears to have been artificially doubled due to a fundamental spreadsheet error.

The policy document, titled "The Right Way" and framed as a "common sense" guide for the party, argues that what citizens ultimately desire is a government competent enough to solve the practical problems for which it takes responsibility. Within a section warning that sophisticated economic modelling should never serve as a substitute for grounded political judgement, the document takes aim at various official estimates surrounding the cost of transitioning the United Kingdom to a net-zero carbon economy.

However, in its critique, the Conservative publication asserts—incorrectly—that the government’s official independent adviser, the Climate Change Committee (CCC), had previously placed the total cost of reaching net-zero at nearly £1 trillion. Specifically, the booklet states: "In 2020, the CCC estimated that its route to net-zero would cost £957bn."

In reality, the official figure published by the CCC in its 2020 advisory report was precisely half that amount, standing at £478bn. Furthermore, the committee released a revised estimate of £108bn, driven largely by the rapidly falling costs associated with electric vehicles (EVs) and low-carbon infrastructure.

Spreadsheet Error and Double-Counting

The erroneous claim reproduced in the Conservative Party document appears to originate from a misinterpretation of a supplementary data file released alongside the CCC’s 2020 report. This spreadsheet contained a detailed sectoral breakdown of the additional capital investments required to construct a net-zero economy over a 30-year period spanning from 2020 to 2050.

The file detailed capital expenditures, listed as CAPEX, encompassing everything from low-carbon electricity generation plants to residential heat pumps and electric vehicles. These extra capital investments added up to a cumulative total of £1.38 trillion over the three-decade timeframe. When measured against projected operational savings, categorized as OPEX, which amounted to £0.90 trillion over the same period, the net combined total of CAPEX and OPEX came to £478bn.

In addition to the annual sectoral breakdowns, the spreadsheet also featured a summary line providing combined totals for each individual calendar year. It appears that a subsequent analyst reviewing the data inadvertently added these annual aggregate totals on top of the individual component figures, resulting in the underlying costs and savings being accidentally counted twice.

This double-counted calculation yielded the exact figure of £957bn that subsequently found its way into the Conservative Party’s policy booklet.

When the CCC published its comprehensive analysis in 2020, it emphasized that the net cost of £478bn amounted to less than 1% of the UK’s gross domestic product (GDP) over the course of 30 years. The committee noted at the time that the substantial upfront capital investments required would not only generate long-term operational savings by curtailing expensive fossil-fuel imports, but would also provide an overall net boost to national GDP of around 2%.

Subsequent updates from the advisory body have further altered the financial landscape of the transition. In 2025, the CCC adjusted its cumulative investment cost projections to £670bn and operating savings to £562bn, yielding a revised net total of £108bn between 2025 and 2050—representing less than 0.2% of GDP. Earlier this year, the committee underscored that achieving net-zero emissions would ultimately cost less than enduring a single major fossil-fuel price shock, while delivering economic and social benefits valued at £110bn annually.

Tracing the Paper Trail

The Conservative document explicitly references the CCC’s 2020 advice on the UK’s sixth carbon budget as the source for the £957bn figure, despite that official advice containing no such amount.

Investigative tracking indicates that the earliest online appearance of the £957bn figure can be traced back to an article published on January 12, 2026, by retired engineer and self-described "accidental energy analyst" David Turver. Just a day later, Turver reiterated the flawed figure in a formal report prepared for the free-market Institute of Economic Affairs, explicitly citing chart data from the CCC’s 2020 supporting information.

However, the underlying spreadsheet behind that specific chart only totals £478bn. The discrepancy stems from the identical procedural mistake of summing the annual total rows alongside the component values, thereby duplicating the financial burden.

Turver’s subsequent reports have previously generated widespread media attention, triggering various inaccurate headlines claiming that net-zero would cost anywhere from £7.6tn to upwards of £9tn. These higher figures were similarly derived from analytical models that made the implicit assumption that fossil fuels, alongside the combustion-engine vehicles, heating boilers, and power stations utilizing them, operate completely free of charge.

Following the circulation of Turver’s report and articles in early 2026, the erroneous £957bn figure was repeated in March by the Great British Think Tank, an organization that utilizes the guiding tagline "data, not vibes" and asserts that all its figures are sourced strictly from official public bodies. Months later, the exact same figure was incorporated into the Conservative Party’s "Right Way" policy booklet, embedding the spreadsheet mistake into mainstream political discourse.