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Iceland’s Carbfix Turns Carbon Dioxide Emissions into Stone

While visiting Iceland last week, Canadian Prime Minister Justin Trudeau dropped by Carbfix, an Icelandic company that wants to tackle climate change by turning carbon dioxide into stone:

Carbfix doesn’t simply freeze carbon dioxide—that’s dry ice, and that will evaporate right away even on the coldest day in Reykjavik (which is actually relatively mild, thanks to the Gulf Stream, but I’m distracting myself). Instead, Carbfix dissolves carbon dioxide in water, then injects that Perrier into basalts and other rock formations that react with the carbonated water and form new minerals. Here’s Carbfix’s simple explanation:

Trees and vegetation are not the only form of carbon drawdown from the atmosphere. Vast quantities of carbon are naturally stored in rocks. Carbfix imitates and accelerates these natural processes, where carbon dioxide is dissolved in water and interacts with reactive rock formations, such as basalts, to form stable minerals providing a permanent and safe carbon sink. The Carbfix process captures and permanently removes CO2. The technology provides a complete carbon capture and injection solution, where CO2 dissolved in water – a sparkling water of sorts – is injected into the subsurface where it reacts with favorable rock formations to form solid carbonate minerals via natural processes in about 2 years. For the Carbfix technology to work, one needs to meet three requirements: favorable rocks, water, and a source of carbon dioxide.

Carbonated water is acidic. The more carbon you can pack into water, the more acidic the fluid will become. Carbfix’s carbonated water reacts with rocks underground and releases available cations such as calcium, magnesium and iron into the water stream. Over time, these elements combine with the dissolved CO2 and form carbonates filling up the empty space (pores) within the rocks. The carbonates are stable for thousands of years and can thus be considered permanently stored. The timescale of this process initially surprised scientists. In the CarbFix pilot project, it was determined that at least 95% of the injected CO2 mineralizes within two years, much faster than previously thought.

The injected carbonated water is denser than the surrounding water in the geological formation and therefore has the tendency to sink after it has been injected. This differs from more conventional methods of carbon capture and storage, which depend on cap rock to prevent possible leakage of gaseous CO2 injected into deep formations. Young basaltic rocks are highly fractured and porous such that water seeps easily through the interconnected cracks and empty spaces underground [Carbfix, “How It Works,” retrieved 2023.07.02].

Carbfix says the basalts that work best with its process are found, among other places, on ocean ridges, and Iceland is the protruding crown of the Mid-Atlantic Ridge. Carbfix provides this map showing in chalky yellow the places where its carbon-fixing process would find the most fertile rock formations:

Carbfix, mineral storage atlas, screencap 2023.07.02.
Carbfix, mineral storage atlas, screencap 2023.07.02.

Summit Carbon Solutions plans to pipe carbon dioxide from ethanol plants across the upper Midwest up to North Dakota, which appears to have no good rock for this carbon-fixing process. But Minnesota and Iowa do:

Carbfix, mineral storage atlas: close-up on United States, 2023.07.02.
Carbfix, mineral storage atlas: close-up on United States, 2023.07.02.

Maybe Kristi Noem’s rich Iowa Republican pals are running their pipeline the wrong way. Instead of shipping CO2 to the North Dakota oil fields (where they’re just going to sequester the gas, not use it for fracking), perhaps Summit Carbon Solutions needs to reverse its current, add Carbfix to its list of partners, and plow that CO2 right into that big strip of good carbon-fixing rock running west of Des Moines from Omaha to Albert Lea.

Of course, Carbfix’s fixing also takes a lot of water. Carbfix is working on using seawater for its process, so perhaps the most forward-looking route for Summit Carbon Solutions and other CO2 pipeliners would be to ship their gas down to that friendly yellow geology down by the Gulf of Mexico or out in the Cascade Mountains, where they could use seawater instead of dwindling prairie aquifers for carbon mineralization.

Scaling up and deploying Carbfix’s technology in the Midwest wouldn’t get rid of the carbon dioxide pipelines that are causing so much consternation among landowners and the John Birch Society. Summit Carbon Solutions would still want pipelines to carry carbon dioxide from South Dakota’s ethanol plants to whatever carbon-friendly rock formations they can find in Iowa, Minnesota, or farther-flung locales. But maybe the ethanol industry could look at Carbfix’s process and maps and focus its production in places where it could plow its carbon emissions right back into ground and lock that CO2 up in local rock.


  1. e platypus onion 2023-07-02 09:01

    From the caliber of magat pols I have seen over the years, Carbfix has already turned magats brains to rocks.

  2. DaveFN 2023-07-02 11:08

    Significant technical challenges and geographic and geological limitations exist for this process as for any process that would claim to be the answer or even part of the answer to carbon dioxide sequestration strategies. There is no advance assurance that carbon dioxide sequestration under caprock as taken for granted in the proposed Summit project will be permanent as promised. Current focus on eminent domain, as relevant as it is, has detracted from the technical issues involved. What sounds good in principle overshadows what is ultimately involved in practice.

    One can find a great deal on the basalt approach and its proponents. Like any technical approach, profit by some entity is invariably the driving force that determines implementation leaving aside critical geological specfics. Science simply is not settled enough, however much a naive realist approach to science would have people believe, to predict the success of such mammoth-sized experiments that profiteers (and policy makers) simplify and make sound like a piece-of-cake.

    “But maybe the ethanol industry could look at Carbfix’s process and maps and focus its production in places where it could plow its carbon emissions right back into ground and lock that CO2 up in local rock.”

    Maybe but asking quite a bit. The best place for ethanol production per se is South America, and the best crop for its production is sugar cane with its multiple crops per year, and not Midwestern corn. The world is far from integrated when it comes to policy and chemical production let alone carbon dioxide mitigation. Again, profit is the primary driver—witness fentanyl synthesis in Mexico from chemicals produced in China with sales elsewhere. Supply chains in a vacuum, ie, isolated from the entirety of the global chemical economy, are a no-brainer for profiteers.

    That said, we have no reason to think Summit Solutions’ solution is in any way the best “solution” when it comes to carbon dioxide mitigation, driven as it is by tax credit profiteers and being but a drop-in- the bucket for carbon dioxide mitigation as any back-of-the-envelope calculation will show—if, that is—it is even technically feasible in practice and not just in principle.

    As we realized decades ago, there is no single, monolithic answer to the energy crisis. Similarly there is no single monolithic answer to the carbon dioxide crisis. A proliferation of approaches will be the best we can do. But some approaches are more intelligent than others, and it takes more intelligence than we find in profiteers.

  3. All Mammal 2023-07-02 11:52

    There is a way to put the CO2 into concrete, which actually fortifies it. Or…. we could forgo all this earth-heating and resource guzzling if we just plant one billion trees. For free. And get some shade out of the deal. 2x the cooling effect yeah! 3x if you count transpiration. Actually, the benefits increase exponentially, just ask my birds and squirrels. Some trees, like my black walnuts, will even feed us. Her nuts are tough to crack so this year I am trying out a popular British pub pickled walnut recipe that uses them while they’re still green. My hands are dyed black and they reek. We’ll see if the Britts are onto something this fall. Trees know best what to do with our fossil-fuel-burning bi-product over-abundance.

  4. DaveFN 2023-07-02 18:43

    Cement manufacture accounts for approximately 8 percent of global carbon dioxide emission and carbonation of cement both after cure (an extraordinarily slow and natural process to the depths of a few millimeters at best) and before full cure to concretization is currently under intensive investigation and has been for some time (who doesn’t want to get in on the sequestration tax credits by one means or expertise or another?).

    As far as carbonation of cement as a sequestration strategy the results are far from conclusive in terms of “fortifying” concrete. At the risk that comes from citing the conclusions from a single source here are some recent findings:

    “It was found that the rising CO2 uptake of ingredient materials subjected to pre-carbonation treatment does not necessarily benefit the mechanical properties of the cement-based composites with the carbonated materials. For a specific material, there may exist a CO2 uptake threshold over which high CO2 uptake tends to be deleterious, e.g. for the mechanical properties. In terms of the influence of accelerated carbonation curing on the compressive strength of cement-based composites at early ages, both positive and negative influences were identified. Corresponding mechanisms behind such contrary influences were critically discussed. It was noted that over-intensified early-age carbonation curing could compromise the strength properties of cement-based composites both in the short and long terms.”

    Liang Li, Min Wu. An overview of utilizing CO2 for accelerated carbonation treatment in the concrete industry, Journal of CO2 Utilization
    Volume 60, June 2022.

    As far as pickled walnuts, try vinyl or latex gloves to prevent staining of hands from juglone oxidation. One had best have an available and affordable source of English cheddar to counteract one’s trouble.

  5. sx123 2023-07-02 20:03

    I have a better idea: quit pulling carbon from the ground, and then spending money to put it back.

  6. Scott Ehrisman 2023-07-04 00:47

    I keep saying it, they are NOT building a carbon pipeline, they are building a hazardous waste pipeline that they can transport anything in, like oil. It is much easy to get approval for a carbon pipeline than a oil pipeline, even though they are having trouble with the latter.

  7. Algebra 2023-07-04 08:04

    Your map of yellow chalky areas looks a lot like a map of seismic instability to me.

    And they are going to use the compressed CO2 for fracking. They are just calling it “enhanced oil recovery” now. The tax credits are lower for EOR uses than for permanent sequestration, but still available.

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