Direct-Air Sequestration Facility in Iceland Achieves 99.4% Mineralization Efficiency

A fictional direct-air capture facility in Iceland says its live field node is converting captured carbon dioxide into stable rock with 99.4% mineralization efficiency, according to the Hafnor Carbon Mineral Project. This report is part of BreakingNews24hr's illustrative demo edition.

From air to rock

Large fans draw air through filters that bind carbon dioxide. Heating the filters releases a concentrated stream, which is dissolved in water and injected deep into volcanic basalt. There the dissolved gas reacts with minerals in the rock and forms solid carbonate.

The project says that in this scenario, 99.4% of injected carbon dioxide mineralized within the monitoring period (illustrative figure). Because the carbon becomes rock, the risk of it leaking back into the air is considered very low.

• Capture: filters bind carbon dioxide from ambient air.
• Injection: the gas is dissolved in water and pumped into basalt.
• Mineralization: the dissolved gas reacts and hardens into carbonate rock.

The caveat that matters: lifecycle emissions

High mineralization efficiency is not the same as high net removal. Building the plant, making the filters and powering the fans and heaters all carry emissions. If that energy comes from fossil sources, the net benefit shrinks.

"Efficiency in the ground is the easy number to celebrate. What the public needs is a full lifecycle account, from manufacturing to energy supply to water use." — Dr. Elin Brandt, climate systems analyst at the (fictional) Norrvik Policy Institute

The project states that its node runs on renewable geothermal heat and electricity, and it has committed to publishing a lifecycle assessment. Outside reviewers say they will wait for that document before accepting any net-removal figure.

Scale and cost

The field node is small. Capturing a meaningful share of annual global emissions would require thousands of far larger facilities, along with water supplies and suitable rock formations. Costs are also high, and capture is widely seen as a complement to, not a replacement for, cutting emissions at their source.

Local residents in the scenario have raised practical questions about water use and land. The project says it recycles water where possible and will hold public meetings before any expansion.

How the result was measured

The project tracked the injected gas using chemical tracers mixed into the water stream. Sampling wells downstream of the injection point were tested regularly to see how much of the tracer carbon remained dissolved and how much had turned to solid mineral.

Independent chemists say tracer methods are reliable but need careful calibration, particularly when rock chemistry varies from place to place. The project has invited outside laboratories to repeat the analysis on stored samples, and says it will publish any differences it finds.

The project also stresses that this is a field node, not a finished commercial plant. It exists to test the process under real conditions, collect operating data and show whether the numbers hold up as the equipment runs for longer periods.

What to watch next

• Release of the full lifecycle emissions assessment.
• Independent verification of the mineralization data.
• Whether a second, larger node can match the efficiency at scale.