The Lower Thames Crossing has taken one step closer to reducing its carbon foot print after pledging to purchase six million kilograms of hydrogen.

It signals National Highways’ intent to have net zero maintenance and construction emissions for the multi-billion pound development by 2040.

The purchases, if the project is approved, will help accelerate the construction industry’s shift away from diesel and “kick start” the development of a hydrogen ecosystem in the Thames Estuary.

If built, the tunnel, which will be near Gravesend, will help link Kent to Essex.

National Highways’ commitment to being net zero will see the crossing explore carbon neutral construction, with the scheme looking to remove an estimated total of 66 million litres of diesel from its worksites.

The transport agency is aiming to buy the supply, storage and distribution of over 6 million kilograms of hydrogen to use on the project, which will replace around 20 million litres of diesel.

Projects such as HS2 have trialled small hydrogen generators, however the Lower Thames Crossing would be the first in the UK to use the fuel on a large scale to power its major construction vehicles such as excavators and dump trucks.

Executive director of the project Matt Palmer said: “The proposed Lower Thames Crossing is designed to be the greenest road ever built in the UK, with the aim of being carbon neutral in construction.

“At the heart of these plans is the use of clean low-carbon hydrogen power, and by using it on such a large scale to power our heavy construction machinery that is traditionally hard to electrify, we can significantly reduce our carbon footprint, accelerate the construction industry’s shift away from diesel, and help kick start the creation of a hydrogen ecosystem in the Thames Estuary.”

MP Nusrat Ghani, minister for industry and economic security, said: “Last month we unveiled our new route map to drive diesel out of construction, marking a vital step towards achieving our ambitions of net zero by 2050.

“I’m pleased to now see National Highways' plans to replace diesel with hydrogen on the proposed project.

“This will not only drive forward our construction sector’s net zero transition but also help to create a new hydrogen ecosystem in the Thames Estuary, moving us forward towards a cleaner, greener industrial future.”

National Highways will work closely with the Department for Transport and the Department for Energy Security and Net Zero to ensure the hydrogen purchased for the proposed scheme helps to drive decarbonisation and strategic development.

Kate Willard, chair of the Thames Estuary growth board, said: “I am delighted to see the Lower Thames Crossing leading the charge to net zero in the construction sector.

“We have proven the demand-led case for investment in hydrogen in the Thames Estuary, and the Lower Thames Crossing will be instrumental in making this a reality.

“This extraordinary and much needed transport project is a clear demonstration of how we can make a successful transition away from fossil fuels not only in construction but also other sectors including maritime and logistics.”

Changes to green measures in the plans have been questioned by opponents and campaigners who claim they raise more questions than answers.

The cost of the oft-delayed project, which rose to £9bn under the resubmitted plans, have also been labelled “low value for money” by an independent public spending watchdog, amid concerns over its long-term sustainability.

The detailed examination of the Lower Thames Crossing by the government’s independent planning experts, the Planning Inspectorate, began on June 20.

If the plans are approved, construction is currently expected to start in 2026.

Laura Blake, chair of Thames Crossing Action Group, said: “There are no guarantees that any of this can or would happen, if the proposed LTC goes ahead. Even if it did the cost of greener construction is predicted to be more than three times as much, and supply of green hydrogen is limited. Large amounts of electricity are needed to produce hydrogen, and this comes at a time when we have shortages of electricity in the country.

“The cost associated with greener construction would push the already high cost up even further, and force the already low Benefit Cost Ratio down. Value for money is something many, including government officials and the project examiners are already questioning.

“There is nothing green about the proposed LTC, it would be hugely destructive and harmful, and it fails to meet scheme objectives, it is simply not fit for purpose. We welcome the Climate Change Committee’s call for an urgent review of all current and future road building, which we believe should result in the scrapping of the proposed LTC."