The new carbon industry

From the frosted windows of the cabin, the largest geothermal power plants transfigure the landscape. On the expressway, road one, it took nearly one hour and twenty minutes by snowplough to reach the Orca site from the Icelandic capital Reykjavik. In the distance, emerald mountains browned by frost. And on the plain, in the middle of white smoke and layers of concrete, three small silver domes connected by huge pipes appear. Behind, a storefront: Carbfix, straight out of a futuristic tale.

At the origin of the project, four founding partners met in 2006. Around the table were Reykjavík Energy, the University of Iceland, the University of Iceland, the CNRS of Toulouse and the Earth Institute of Columbia University. The project is led by the project manager Hólmfríður Sigurðardóttir, Dr. Sigurður Gíslason and Dr. Eric Oelkers. As early as the following year, they joined several other research institutes; in particular Amphos 21, Climeworks and the University of Copenhagen. Their idea: imitate and accelerate a natural process by which the interaction of rock formations and dissolved CO₂ form thermodynamically stable carbonate minerals, real hosts for permanent storage and harmless to the environment.

In just seven years, Carbfix went from an idea on paper to a fully operational, profitable and environmentally friendly industrial process that captured CO₂ and H2S from emission sources and stored them permanently as rock in the basement. This rapid and successful development of innovation was based on collaboration between industry and academia, with the active participation of interdisciplinary scientists, engineers, and workers. The next generation of climate solutions experts have simultaneously been actively trained through undergraduate and graduate research positions.

During the early years of the project, emphasis was placed on optimizing the method through laboratory experiments, studies of natural analogs, reservoir modeling, and characterization of the Carbfix pilot injection site, often referred to as the Carbfix1 site, gas capture, injection, and monitoring equipment. This work was carried out simultaneously with a comprehensive licensing process, during which more than ten permits were acquired for planned field operations.

Pilot injections were carried out in 2012 at the Carbfix pilot injection site in collaboration with ON Power, located 3 km southwest of the Hellisheidi power plant, in southwest Iceland. From January to March, 175 tons of pure CO2 were dissolved and injected at a depth of about 500 m at about 35°C, and from June to August, 73 tons of 75% CO2-25% H2S gas mixture from the Hellisheidi geothermal power plant were injected under the same conditions. The results of the pilot phase were published in Science in 2016, which confirmed the rapid mineralization of the injected CO2.

After the success of the CarbFix pilot operations and the first indications of rapid mineral storage, the industrial-scale transition of CCS operations at the Hellisheiði power plant and the simultaneous capture of CO2 and H2S through a simple single-stage water washing process. A full-scale capture plant for two of the six high-pressure turbines was built next to the turbine room, which started operating on a pilot industrial scale in 2014. Since then, the installation has been operating continuously, without incident, and the collection capacity was doubled in 2016.

The plans are to bring emissions from the plant back to near zero in the coming years. The cost of CCS operations on site in Hellisheiði is 24.8 US dollars per ton, less than the recent average price of a carbon quota in the Community emissions trading system. By applying the Carbfix process to capture and mineralize H2S, instead of conventional sulfur removal methods, which consist of converting H2S into elemental sulfur or sulfuric acid, significant economic benefits have been achieved. Thus, the investment and operating costs of the Carbfix approach are only 3 to 30% of those of conventional sulfur removal methods.

The company seeks to exploit the natural process that occurs when carbon dioxide mineralizes in porous rock. Carbfix focused primarily on two projects: first, capturing carbon dioxide and hydrogen sulphide from emissions from the Hellisheiði power plant, and second, capturing carbon dioxide directly from the atmosphere. Carbfix manages to capture about a third of the carbon dioxide emitted by the Hellisheiði power plant, which is equivalent to around 12,000 tons per year. In addition, around 5,000 tons of hydrogen sulphide are removed from the plant's emissions. This process involves capturing carbon dioxide and hydrogen sulphide from emissions by dissolving them in water. This produces “a rather disgusting sparkling sulphur water,” as Sandra says, which is injected deep into Hellisheiði's basalt. Since sparkling water has a higher density than water found in the ground, it does not rise, but sinks deeper into the strata. In addition, as it is very acidic, it releases metals from the rock, which then mineralize the CO2 mixture.

The Carbfix process has been applied to significantly reduce CO2 and H2S emissions from the Hellisheiði power plant since 2014, after successful pilot-scale injections in 2012. The technology can be adapted to other carbon-emitting industries, such as the production of steel, iron, and cement, and several pilot projects are under way in an effort to adapt the technology to other industries and circumstances. Carbfix was incorporated as a subsidiary of Reykjavik Energy (OR) at the end of 2019 and started operating as a separate entity on 1 January 2020. The company's mission is to become a key instrument in the fight against the climate crisis by reaching one billion tons of permanently stored CO₂ (1 GtCO2) as quickly as possible.

“During the first years of the project, the main objective was to optimize the method through laboratory experiments, studies of natural analogs, and the characterization of the Carbfix pilot injection site, often referred to as the Carbfix1 site, where the pilot injections took place. The design and construction of the gas capture, injection and monitoring equipment were carried out simultaneously,” explains Kári Helgason, Innovation Director. Today, the technology is ready to be scaled up all over the world.