Business leaders have called on the chancellor to back the Acorn carbon capture and storage (CCS) project in Aberdeenshire.
The project at St Fergus would take greenhouse gas emissions and store it in depleted gas reservoirs under the North Sea.
The project missed out on support in 2021, which instead went to two areas in the north of England, and was placed on a reserve list for future backing.
Signatories on a letter to Rachel Reeves include oil tycoon Sir Ian Wood and business organisations such as the Scottish Chambers of Commerce. The UK government said Acorn had already received more than £40m for its development.
The letter argues that the project has faced two decades of setbacks, and that it is needed to help Scottish industry decarbonise.
It warns that failing to act now threatens thousands of jobs, billions of pounds of investment, and economic growth.
The letter states: “We write to urge the UK government to commit, in its comprehensive spending review, to progressing Scotland’s only opportunity for industrial decarbonisation, the Acorn CCS project, as an immediate priority.
“There has never been a more important time for this project to proceed at pace.
“Scotland must not be left behind.”
Commenting on the letter, the UK government said: “Acorn has already received over £40m for development and it is our firm ambition to proceed with the projects in the Track-2 clusters.
“Scotland is at the forefront of the drive towards clean energy, with Great British Energy’s headquarters located in Aberdeen and the recent £56m award for Cromarty Firth to become the UK’s first floating offshore wind port capable of making turbines at scale.”
It added: “Our historic funding for two initial carbon capture clusters is just the first step in developing a self-sustaining market for the industry.”
