Plans to build an enormous £16.5 billion data centre on the site of the former Chapelcross nuclear plant have been submitted.
The Scottish Greens, who oppose the project, claim the 1GW data centre in the south of Scotland would be the biggest in world.
CX Tech Ltd have said the project, near Annan, Dumfries and Galloway, would deliver around 500 full-time jobs.
The company said it wants to redevelop the brownfield site as a “net zero operational technology campus” including eight data centres, a dedicated training centre and “associated infrastructure”.
In total, it is seeking permission for up to 162,000 square metres of data centre floorspace.
Graeme Anderson, chief executive of CX Tech Limited, said: “This is a once-in-a-generation opportunity for Dumfries and Galloway and for Scotland.
“Chapelcross has the potential to bring together our renewable energy strengths, digital infrastructure and high-value jobs in a way that few other sites can.
“We have an opportunity to seize that potential now, creating a new economic future for a site that has played an important role in Scotland’s energy story for generations.”
CX Tech Ltd said proposals also include energy-efficient buildings, sustainable drainage and landscaping.
However, the Scottish Greens urged for the project to be rejected, saying it would use around seven million MWh of energy a year – the equivalent of the energy used by more than two million homes.
South Scotland MSP Laura Moodie said: “This is one of the most seriously concerning data centre applications to date. The proposed site alone would use an unsustainably high amount of energy.
“While household energy bills keep going up, hyperscale data centres will only make that worse.
“The average household in Ireland now pays an extra £300 a year on energy, because of data centres. At the same time, tech giants and billionaires are making huge profits off of these applications.”
She said locals were being given just weeks to respond to the “world’s largest data centre campus”.
She said the proposals are “reckless and endanger our energy supply and natural environment”.
“Until we have a clear national strategy from the Government, this proposal cannot proceed,” she added.
“This application must be rejected because of the risks and consequences it could bring to our energy grid and our rural communities.”
Our ambition is for investment at Chapelcross to deliver lasting value for the local area, helping to retain skills, attract new opportunities and support the wider economy of Dumfries and Galloway
A spokesperson for CX Technology Campus said the company had undertaken “a comprehensive environmental impact assessment” and said the campus would use only locally and regionally generated renewable energy.
“It will not compete with local homes and businesses for their electricity supply,” they added. “It will use closed-loop cooling technology designed to minimise water requirements, while fossil-free fuel is proposed for emergency back-up generation rather than diesel.
“The economic and community benefits are also central to the proposal.”
The company said 750 jobs would be created during construction, with about 450 permanent direct jobs created too alongside 40 apprenticeships.
“Our ambition is for investment at Chapelcross to deliver lasting value for the local area, helping to retain skills, attract new opportunities and support the wider economy of Dumfries and Galloway,” the spokesperson said.
A Scottish Government spokesperson said: “As this is a live planning application, it would be inappropriate to comment.”