From Gas to Stone: KAUST Demonstrates CO₂ Sequestration Underground with Reduced Water Usage

Researchers at King Abdullah University of Science and Technology (KAUST) have demonstrated that carbon dioxide (CO₂) can be permanently converted into solid rock underground using a system that recycles water already present deep underground, removing one of the main barriers to deploying this approach in arid environments.
 In a field trial in western Saudi Arabia, researchers injected CO₂ deep underground into volcanic rock in Jazan Region. Rather than relying on scarce freshwater, the system uses a closed-loop system that recirculates water from deep underground. As CO₂ moves through the rock, it reacts with surrounding minerals and slowly hardens into stone, trapping the carbon in a stable, permanent form.
 According to a press release issued by the KAUST today, carbon mineralization is not a new concept, but until now it has depended heavily on access to large volumes of water and highly reactive volcanic rock. Previous estimates suggested the process could require up to 20–50 times more water than the amount of CO₂ stored, limiting its use outside specific geological settings.
 In the KAUST-led pilot, 131 tons of CO₂ were injected underground, with monitoring indicating that around 70 percent had been converted into solid minerals within ten months. The work was carried out in basalt formations estimated to be between 21 and 30 million years old, significantly older than those used in earlier flagship demonstrations, suggesting that suitable sequestration conditions may be more widespread than previously assumed.
 Professor in Energy Resources and Petroleum Engineering at KAUST Hussein Hoteit said, “Carbon mineralization has long been seen as one of the most secure ways to entrap CO₂, but its practical application has been limited by water availability. What we have shown here is that by working with the subsurface system, rather than depending on surface resources, it is possible to make this approach viable in environments where water is scarce.”
 The research was led by KAUST scientists and delivered through a field trial in collaboration with Saudi Aramco, which operated the site and supported injection and monitoring activities. KAUST researchers analyzed the subsurface processes to confirm how CO₂ is converted into solid minerals underground.