A little over a year after launching carbon capture operations at ON Power‘s Hellisheiði power plant in Iceland, Carbfix has announced that its systems have achieved a 99.6% CO2 capture efficiency.
The company said that in the period between 1 July 2025 and 30 June 2026, the installation at Hellisheiði successfully captured 99.6% of the carbon dioxide and all of the hydrogen sulfide.
Once captured, the CO2 and the H2S were dissolved in water and sent for permanent storage in the bedrock.
This process represents the first stage of CO2 mineral storage, and the results achieved through this deployment demonstrate the high efficiency of Silverstone – a project developed jointly by Carbfix and ON Power.
Announced in mid-2025, Project Silverstone has received ∼ $4.4 million (€3.87 million) in financial support from the EU Innovation Fund.
Carbfix’s mineralization approach
Since implementing Carbfix’s method, the Hellisheiði Power Plant has contributed to the mineralization of more than 120,000 tonnes of carbon dioxide and over 50,000 tonnes of H2S in rock formations.
Carbfix developed this technology inspired by the same process that occurs naturally but takes thousands of years to mineralize CO2 and H2S.
According to the company, its approach demonstrated through Silverstone immediately dissolves the carbon dioxide in water and then transforms it into new minerals within only two years.
To facilitate the mineralization, Carbfix injects carbonated water into a reactive basalt formation underground. This approach, the company highlights, curbs the climate impact of geothermal power production while also contributing to the safe and cost-effective management of hydrogen sulfide.
Relevant: ON Power & Carbfix Officially Launch CDR At Geothermal Plant, Backed By EU Funding
Leveraging the support from the EU Innovation Fund, Carbfix and ON Power focused on the development and expansion of Silverstone’s technology.
These efforts, the two partners state, have simultaneously unlocked insights and knowledge on the role and potential of Icelandic innovation and engineering expertise in the fight against greenhouse gas emissions.
Read more: Carbfix Receives Europe’s First Onshore CO2 Storage Permit Under EU Law
