Cornish geothermal power plant produces battery-grade lithium
Cornwall plant begins commercial lithium production from geothermal brine
Cornwall has moved from pilot testing to commercial production of lithium, extracted from the same geothermal brine that generates renewable electricity at the United Downs site near Redruth. Geothermal Engineering Ltd says the facility now produces 100 tonnes of lithium carbonate annually while supplying power to the grid. The site uses fluid pumped from more than five kilometres underground, described as the deepest well drilled in the UK.
This matters because the UK imports virtually all its lithium for batteries. A domestic source reduces supply chain risk, particularly for manufacturers tied to electric vehicle production or battery assembly. It also offers a dual revenue model that could make geothermal projects more financially viable than power generation alone.
The project taps hot geothermal fluid from granite formations deep below Cornwall. Consequently, it generates baseload renewable electricity before the same water passes through lithium extraction and is reinjected underground in a closed loop. This approach avoids the land use associated with conventional lithium mining or evaporation ponds.
Lithium concentrations in Cornwall's geothermal brines are unusually high. Earlier sampling by Cornish Lithium reported averages of 220 milligrams per litre, with peaks reaching 260. Subsequent reports on United Downs brine put concentrations above 340 parts per million, reinforcing the site's reputation for lithium-rich geothermal fluid.
February 2026 marks shift to commercial operation
Geothermal Engineering Ltd began commercial lithium carbonate production alongside electricity generation in February 2026. Initial output stands at 100 tonnes per year, described variously as battery-grade or technical-grade lithium carbonate depending on the source. The company frames this as the start of a scaling process rather than a final capacity.
The extraction process is relatively straightforward. Geothermal fluid is brought to the surface to drive electricity generation, then cooled to around 50 degrees Celsius for lithium recovery. After extraction, the water returns underground. This closed-loop design means the same brine circulates continuously without depleting the resource or requiring disposal.
Geothermal Engineering Ltd has outlined plans to expand significantly beyond the current 100 tonnes. One target cited in recent reporting is 18,000 tonnes per annum within a decade, sufficient for approximately 250,000 electric vehicle batteries each year. Meanwhile, financing from ABN AMRO is expected to support an interim step, lifting production to nearly 2,000 tonnes per year by 2028 or 2029.
The electricity side of the operation reportedly supplies around 10,000 households. Therefore, the site generates two revenue streams from the same geological asset. This dual-purpose model could improve the economics of geothermal projects across the UK, particularly in regions with suitable geology.
High lithium grades strengthen commercial case
Lithium concentration is a critical variable for extraction economics. Higher grades mean more lithium per cubic metre of brine, which reduces the volume of fluid that must be processed for each tonne of output. United Downs brine exceeds 340 parts per million, placing it among the richest geothermal sources globally based on published data.
For context, typical lithium brine operations in South America work with concentrations well below 1,000 parts per million. However, those projects rely on solar evaporation ponds that occupy large areas and take months to concentrate the brine. Cornwall's geothermal approach extracts lithium directly from hot fluid, avoiding evaporation altogether.
The depth of the well is also significant. Drilling to more than five kilometres is expensive and technically demanding, but it accesses hotter fluid with higher mineral content. The heat provides the energy for power generation, while the dissolved lithium provides the feedstock for battery material. As a result, the economics depend on both outputs performing reliably over time.
Scaling from 100 tonnes to several thousand will test whether extraction rates remain stable as throughput increases. It will also reveal whether the brine chemistry stays consistent across different flow rates and operating conditions. These are standard questions for any mineral extraction project moving from demonstration to commercial volumes.
Supply chain implications for UK manufacturers
The UK currently imports all its lithium for battery production. Domestic supply reduces exposure to international price volatility and shipping delays. It also shortens the supply chain for manufacturers assembling battery packs or electric vehicles in the UK, which can improve lead times and inventory management.
Public procurement is another factor. Suppliers bidding for government contracts increasingly face questions about supply chain resilience and environmental standards. A UK source of lithium, particularly one with low carbon intensity due to geothermal power, could strengthen a supplier's position in tenders that prioritize domestic content or net zero credentials.
There are limits to how much domestic lithium can displace imports. Even at 18,000 tonnes per year, United Downs would supply only a fraction of UK battery demand if electric vehicle adoption continues at current rates. Nevertheless, it establishes a foundation that other geothermal sites in Cornwall or elsewhere could build on.
The financial structure of the project also matters. ABN AMRO's involvement suggests institutional confidence in the technology and the revenue model. Financing is often the bottleneck for capital-intensive projects, so securing bank support for scaling is a positive signal for similar ventures.
Eight key points about the United Downs project
- The site is located at United Downs Industrial Estate near Redruth and taps geothermal fluid from more than five kilometres underground, the deepest well drilled in the UK.
- Commercial production began in February 2026 with an initial output of 100 tonnes per year of lithium carbonate, described as battery-grade or technical-grade depending on the source.
- Lithium concentrations in the brine exceed 340 parts per million, among the highest reported in geothermal waters globally based on published sampling.
- The plant also generates renewable electricity, reportedly supplying around 10,000 households from the same geothermal fluid used for lithium extraction.
- Geothermal Engineering Ltd aims to expand production to 18,000 tonnes per year within a decade, sufficient for approximately 250,000 electric vehicle batteries annually.
- Interim scaling supported by ABN AMRO financing targets close to 2,000 tonnes per year by 2028 or 2029.
- The closed-loop process reinjects the brine underground after extraction, avoiding the land use and evaporation ponds associated with conventional lithium production.
- The project provides a dual revenue model that could improve the financial viability of geothermal energy in the UK by adding mineral extraction to electricity generation.
What businesses should consider about domestic lithium supply
Manufacturers using lithium in their products or supply chains should monitor whether United Downs scales as planned. A reliable UK source could offer pricing stability and shorter lead times compared to imports, particularly if global lithium markets remain volatile. It also provides a story for customers and procurement teams who value domestic content.
For companies with net zero commitments, the carbon footprint of battery materials is increasingly scrutinized. Lithium extracted using geothermal power has a lower embedded carbon intensity than conventionally mined lithium, especially when transport emissions are included. This could matter for Scope 3 reporting and for businesses seeking to reduce supply chain emissions.
Businesses operating in Cornwall or the South West should watch for workforce and infrastructure development linked to geothermal expansion. If other projects follow United Downs, the region could develop specialized skills and supply chains around geothermal energy and mineral extraction. That creates opportunities for local suppliers and service providers.
However, the project is still early in its commercial phase. Businesses should not assume that 18,000 tonnes per year is guaranteed or that lithium will be available at scale within a fixed timeframe. Scaling mineral extraction involves technical and financial risks, so any procurement strategy should retain flexibility while monitoring progress.
Companies involved in public sector supply chains should also consider how domestic lithium aligns with procurement policy. Government buyers increasingly favor suppliers who can demonstrate supply chain resilience and environmental responsibility. A UK lithium source strengthens both narratives, particularly if the supplier can document the carbon intensity of the material.
Finally, businesses with sustainability reporting obligations should understand that geothermal lithium fits into several disclosure themes. It relates to critical mineral sourcing, renewable energy use, circular economy principles through closed-loop extraction, and regional economic development. For businesses preparing detailed sustainability reports or responding to investor questions, United Downs offers a concrete example of supply chain innovation in the UK.
We provide compliance support for carbon reporting and ESG disclosure if your business needs help integrating supply chain data into regulatory filings or sustainability reports.
Where to find further information
The Department for Energy Security and Net Zero publishes policy updates on critical minerals and geothermal energy as part of the UK's net zero strategy. Their guidance covers domestic mineral supply and renewable energy infrastructure.
Geothermal Engineering Ltd provides project updates and technical details about the United Downs facility on their website. Similarly, Cornish Lithium publishes data on lithium concentrations in geothermal brines and other sampling results from the region.
The British Geological Survey offers research on UK geothermal resources and mineral potential, including reports on Cornwall's geology and lithium deposits. For businesses tracking battery supply chains, the Faraday Institution publishes research on battery technology and raw material sourcing relevant to the UK automotive and energy sectors.