The carbon emissions from just two planned datacentres in England will exceed all of the fossil fuel company ExxonMobil’s UK emissions, analysis has revealed.

Experts have said this demonstrates the “serious threat” datacentres pose to the UK’s legally binding climate goals.

Analysis by the non-profit group Foxglove reveals that when fully operational, the Wapseys Wood datacentre in Buckinghamshire and the Quest Park datacentre in Bedfordshire will use 1.3GW of power and will produce more than 4.5m tonnes of carbon emissions.

ExxonMobil emitted 3.9m tonnes in 2023, according to the global energy thinktank Ember.

AI datacentres use a massive amount of electricity to power servers and cooling equipment, and to run facility systems. There are currently 315 datacentres in the queue to connect to the UK’s electricity grid, representing 73GW of demand. This is almost double the peak winter energy demand for the entire UK.

Because of the long wait to connect to the grid, the Wapseys Wood and Quest Park datacentres are seeking to build their own on-site gas-fired power stations.

Based on government figures on the carbon intensity of electricity generation, Foxglove has calculated these projects will produce 4.577m tonnes of carbon emissions per year.

A government spokesperson said these figures were “misleading” because of the assumption that both projects will run at 100% utilisation from day one, which they said was “not accurate”.

Tom Hegarty, head of communications at Foxglove, said assuming a 100% utilisation rate followed standard industry practice.

Kierra Box, a trade and environmental regulation campaigner at Friends of the Earth, said the aim was for datacentres to increase load and run at full capacity, and so it was “valid to look at those top level predictions”.

The former England and Wales Green party leader Caroline Lucas described the projected emissions from these projects as “absolutely horrifying”, and said it should be ringing alarm bells right across government.

The government says its own analysis shows there are multiple pathways for this rapid datacentre rollout to fit within the seventh carbon budget, which sets out how the government will reach its international climate targets.

However there remains a high level of uncertainty over how this will work.

Toby Perkins, a Labour MP and chair of the Commons environmental audit committee, which is leading an inquiry into the environmental impact of datacentres, said this analysis was a “potent reminder that without the right measures in place, data centres could represent a serious threat to the environment and to our legally binding climate goals”.

Oliver Hayes, head of policy at the campaign group Global Action Plan, said the two projects were “catastrophic for our carbon budgets”. He said the only way the rapid rollout of datacentres could fit within these budgets was if other elements of the economy were given much stricter carbon budgets.

Sam Hunter-Jones, a ClientEarth lawyer, said every megawatt powering a datacentre connected to the grid was a megawatt that could not be used to replace fossil fuels elsewhere. “The reality is that unchecked datacentre growth is making the transition away from fossil fuels harder, not easier,” he said.

The datacentres are two of the first to be fast-tracked through the government’s nationally significant infrastructure project (NSIP) regime. This regime allows developers to rapidly deliver infrastructure projects by bypassing local planning authorities with decisions instead handled by central government.

Hayes said it was a “very worrying sign” that the government had allowed two gas-fired datacentres to apply into the NSIP regime. “I think that sends an extremely bad signal and demonstrates that they are not serious about addressing the emissions associated with datacentres,” he said, describing it as an “affront to local people”.

Lucas also raised concerns about the projects being fast-tracked, and said it “insulates” them from local scrutiny.

“In order to be able to make sensible decisions on which projects should go ahead and where they should be, we need to have more information in the public domain. We need to have more scrutiny, not less, and yet things like the NSIP regime are moving things in the opposite direction,” she said.

A spokesperson for the Department for Energy Security and Net Zero said: “Datacentres are a vital part of our economy and our everyday lives, helping us interact with the services we need, while driving growth and renewal for communities. We will enable the development and growth of new industries, such as datacentres, by building unprecedented amounts of clean power.”

Waspeys Wood declined to comment. Quest Park did not respond to a request for comment.