Geothermal Engineering Ltd (GEL) has produced lithium carbonate exceeding 99.3% purity at its United Downs geothermal plant in Cornwall.
The company described the material as technical-grade lithium carbonate and claimed United Downs was the first European operation positioned to produce it commercially from geothermal brine.
The operational plant has annual production capacity of 100 tonnes, with GEL targeting output of around 2,000 tonnes per year at United Downs by 2029. It plans to add further sites and increase total production to 30,000 tonnes per year by 2033.
GEL said independent analysis had confirmed the product exceeded its 99.3% purity specification. It claimed the material could be sold directly to battery producers without further refining.
However, GEL did not identify the laboratory responsible, publish a full impurity analysis or describe the material as battery grade. Specifications vary between producers and customers: an Albemarle specification published in a technical report sets minimum lithium carbonate content at 99% for technical grade and 99.3% for battery grade, but also imposes separate limits for contaminants including sodium, magnesium, iron and chloride.
GEL extracts lithium from hot, mineral-rich brine brought to the surface from wells drilled more than 5km into Cornish granite. The brine is also used to generate geothermal electricity at the combined power and lithium-extraction facility.
The company claimed benchmarking had placed its process among the world’s most sustainable lithium-production methods because extraction was integrated with geothermal power generation. It did not identify the benchmarking study or provide comparative emissions figures in its announcement.
GEL chief executive Ryan Law said: “Producing lithium carbonate that exceeds the purity specification for technical-grade material is a major milestone for GEL and an important validation of our technology.
“We are demonstrating that it is possible to produce a high-quality, saleable lithium product in the UK with the highest environmental standards, creating the potential for a more secure and sustainable domestic supply of this critical battery material.”
The development received £1.8 million from the UK government’s Automotive Transformation Fund, delivered through the Advanced Propulsion Centre’s DRIVE35 programme.
APC director of automotive transformation Julian Hetherington said United Downs demonstrated the UK’s opportunity to establish a sustainable domestic lithium carbonate supply chain.
“It will strengthen the UK’s critical minerals supply chain and reindustrialise the country,” he said. “We look forward to continuing to work with GEL as it scales production across the UK.”
The UK government’s Critical Minerals Strategy calls for domestic production to meet at least 10% of aggregate annual demand for critical minerals by 2035. It includes a specific ambition to produce at least 50,000 tonnes of lithium, expressed as lithium carbonate equivalent, domestically by that date.
