A battery manufacturer has listed a site in Wales as the "preferred choice" for a new factory which would create thousands of jobs.
Britishvolt, which plans to produce batteries for electric vehicles, said its preferred location is St Athan in the Vale of Glamorgan.
Luxury car giant Aston Martin has a factory in the town.
Britishvolt, which was launched last December, hopes to make a final decision by the end of August, and start production by 2023 at the Bro Tathan site.
The factory would employ at least 3,500 workers, and create up to 15,000 further jobs in the supply chain, including material suppliers, contractors and local services.
The company said the battery industry is forecast to be worth £5bn domestically by 2025, adding that demand for lithium ion cells across a number of industries, including vehicle electrification, is already increasing dramatically.
The firm is also announcing plans to build a solar park alongside the factory, to support sustainable production of batteries and meet low-carbon objectives.
Lars Carlstrom, chief executive of Britishvolt, said: "We aim to deliver a scalable, onshore production and diverse portfolio of world-class lithium ion batteries, to support the unprecedented transition to electrification, primarily servicing the automotive and energy storage markets."
He added that the area surrounding the Bro Tathan site meets "crucial criteria" including the availability of skilled staff and import and export accessibility.
"The sheer scale of this project means our gigafactory will have one of the top three largest single footprints in Europe", Mr Carlstrom said.
"Our ambition is to become one of the greenest battery producers worldwide, which will be facilitated through the creation of our very own solar park, ensuring a near-carbon neutral electricity input."
A Welsh Government spokesman said: "We have been working with Britishvolt on this project for a significant period of time and we are very pleased they have shortlisted Bro Tathan as a location for its landmark gigafactory.
"We firmly believe that Bro Tathan provides a compelling case particularly for a company looking to become one of the greenest battery producers worldwide".