Summary: A new paper backed by the Institute of Economic Affairs claims Labour’s net zero pathway could exceed £9 trillion by 2050 once wider “carbon costs” are counted, igniting a fresh political row over transparency, energy bills, and whether the UK is being marched into an unaffordable transition without honest numbers.

£9 trillion claim reignites the net zero cost war

A fresh flashpoint has erupted over Britain’s net zero plans after a report cited by the Institute of Economic Affairs (IEA) claimed the total cost could run to more than £9 trillion by 2050.

The argument is simple: official bodies are accused of presenting tidy, optimistic figures while leaving the public to discover the real bill later, through taxes, levies, borrowing, and higher household costs.

“The various public bodies responsible for working out the costs of net zero have not been entirely truthful in their analysis… They have made fantasy assumptions about the cost of renewables and low-carbon technologies.”

David Turver, energy analyst and author of the research

What the main official numbers currently say

Forecasts for the cost of net zero vary wildly, which is exactly why this debate refuses to die.

The Climate Change Committee (CCC) has put forward a much lower estimate, with the report noting claims around £108 billion, a figure that is far below older projections that ran into the trillions.

Meanwhile, the National Energy System Operator (NESO) has published much higher modelling, with figures in the multi-trillion range, including an estimate of about £7.6 trillion under certain scenarios.

Why the IEA paper claims the real total is higher

The IEA-linked critique is not merely that net zero is expensive. The claim is that the public has not been shown the full cost stack.

According to the report summary, the £9 trillion figure is reached by arguing that NESO’s higher-end number does not include “carbon costs of emissions”, which would push the total beyond £9 trillion by 2050.

It also takes aim at assumptions around financing and delivery, including the cost of capital used for renewables projects.

The report highlights examples such as assumptions that the cost of capital for solar and onshore wind could be around 5% and 5.2%, comparable to or below long-term gilt yields, which critics argue is too optimistic for the risk and scale involved.

Claire Coutinho: “We’re flying blind”

Conservative shadow Energy Secretary Claire Coutinho backed the thrust of the criticism, arguing that institutions are operating with “groupthink” and incomplete accounting.

She also pointed to system costs beyond the headline price of turbines and panels, including grid upgrades, constraint payments, and firm backup for when the weather does not co-operate.

“Wildly optimistic assumptions and crippling groupthink in our institutions means we’re flying blind… When I was Energy Secretary I had to pull teeth to make the Energy Department carry out an accurate costing… Ed Miliband has since cancelled that work.”

Claire Coutinho, Conservative shadow Energy Secretary

Reform UK: scrap net zero, cut bills, protect industry

Reform UK used the report to intensify its attack line that net zero is a costly political project that will not deliver cheaper energy.

Richard Tice framed the policy as an economic threat to competitiveness, warning that high energy costs drive investment out of Britain.

“This shocking report on the Cost of net zero exposes the myths and lies… It shows the real cost of net zero will be many trillions of £s, and will not reduce the cost of energy.”

Richard Tice, Reform UK

For voters who backed Brexit on the promise of democratic control and accountability, this row lands hard: if the UK is going to take on a generational bill, the numbers cannot be treated like a messaging exercise.

Badenoch’s stance: “impossible” target and repeal pledge

Opposition to the 2050 target has been hardening on the right, including among senior Conservatives.

Kemi Badenoch has previously described net zero by 2050 as “impossible” and has pledged to repeal what she calls the “failed” Climate Change Act 2008, arguing the target risks living standards or the public finances.

Counter-argument: the cost of inaction and energy security

Supporters of the net zero pathway insist critics ignore the costs of staying exposed to volatile global fossil fuel markets.

Jess Ralston of the Energy and Climate Intelligence Unit argued that energy shocks can be ruinous and that adding domestic renewables improves energy security over time.

“Nobody has a crystal ball on costs of fossil fuels… The recent gas crisis drove the UK to spend over £180billion… Renewables that we already have on the system lowered wholesale power prices by around a quarter in 2024.”

Jess Ralston, Energy and Climate Intelligence Unit

Miliband’s department rejects the £9 trillion framing

The Department for Energy Security and Net Zero rejected the analysis, arguing it assumes there is no cost to remaining on what it calls a “fossil fuel rollercoaster”.

It also pointed to NESO commentary claiming that reaching clean energy goals could save money compared with slowing down, including savings estimates framed on an annual basis.

“We reject this analysis… NESO has made clear that driving for clean energy saves money by fundamentally reducing our exposure to fossil fuel markets… The only way to bring down energy bills and deliver energy security is by making Britain a clean energy superpower.”

Spokesman, Department for Energy Security and Net Zero

The political reality: transparency or a blank cheque

This fight is no longer a niche energy argument. It is a straight political question about trust and living standards.

Labour wants the moral high ground of climate ambition while promising lower bills. Critics say that only works if the full costs are disclosed, including grid build-out, backup capacity, constraint payments, and financing risk.

If ministers cannot publish clear, comparable totals, voters will assume the worst: that they are being handed a blank cheque, and told to smile while paying it.