Underground Carbon Storage Breakthrough Could Supercharge Climate Fight (2025)

(Photo by Dilok Klaisataporn on Shutterstock)

ENSCHEDE, Netherlands — Carbon dioxide pumped underground stays there more securely than we thought, according to a new study that could boost confidence in one of our most promising climate solutions. Advanced 3D computer simulations reveal that CO2 mixes with underground brine remarkably faster than previous calculations predicted, creating a natural trapping mechanism that’s more efficient than scientists realized.

This discovery, made by researchers from the University of Twente in the Netherlands and their colleagues, contradicts earlier assumptions about how injected carbon dioxide behaves when stored deep beneath the Earth’s surface. For years, scientists relied on simplified two-dimensional models that underestimated mixing rates. Now, using advanced three-dimensional simulations, researchers found the process works significantly more efficiently.

How Carbon Storage Works

Carbon capture and storage represents one of our most promising weapons against climate change. The process captures carbon dioxide from power plants and industrial sources before it enters the atmosphere, then injects it deep underground into porous rock formations where it can remain trapped for centuries.

When first injected underground, the CO2 is lighter than the surrounding brine and floats upward, collecting beneath an impermeable rock layer. This arrangement initially seems precarious – if that caprock were to crack, the carbon dioxide could potentially escape.

“Pure CO2 has a lower density than water, but the situation changes when CO2 is dissolved in water. When the two are mixed, the total volume decreases, creating a denser liquid,” explains Marco De Paoli, head of the research project, in a statement. “Water with a high CO2 content has a higher density than water with a lower CO2 content and therefore sinks.”

This density difference creates a fascinating dynamic. As the CO2-rich water sinks, it forms distinctive finger-like structures called “plumes” that increase mixing through a process called convection.

“Because water with a higher CO2 content has a higher density than water with a lower CO2 content, the dynamics in the porous rock are highly interesting,” says De Paoli. “Where the CO2 concentration is highest, the mixture sinks faster, which in turn ensures even better mixing.” This results in a network-like pattern of areas with higher and lower CO2 concentrations.

The Discovery: Faster Mixing in 3D

The research team used powerful supercomputers to run simulations that tracked the fluid dynamics occurring when carbon dioxide dissolves into brine. Their work, now published in Geophysical Research Letters, revealed that in three-dimensional simulations, the dissolution rate was 13.5% higher than in two-dimensional models – substantially different from previous estimates suggesting a 25% difference.

From their calculations, the team was able to derive simple models that can now be used by engineers to predict CO2 flow in the ground and design injection strategies without having to carry out complex computer simulations for every situation.

The study found this process unfolds through several distinct phases. First comes a diffusion-dominated phase where carbon dioxide slowly dissolves at the interface. Next, the CO2-rich layer becomes unstable and forms the small plumes that grow downward. These fingers eventually merge with neighbors to form larger, persistent structures. Finally, as the domain becomes saturated, mixing gradually slows.

Real-World Impact

To demonstrate practical applications, they applied their model to the Sleipner site in the North Sea – one of the world’s first and largest carbon storage projects. Their calculations predicted it would take about 10 years to dissolve 100 kg/m² of carbon dioxide at this site. The model also suggested it would take less than 20 years to achieve 50% dissolution of injected CO2, but more than 100 years to reach 90% dissolution.

The geological conditions needed for this storage method aren’t rare. “You could use depleted oil reservoirs. There are also large areas called saline aquifers, located under the seabed or inland, where CO2 storage would be possible according to this scheme. At least six saline aquifers are also present in Austria,” notes De Paoli.

Once the CO2-containing water sinks downward, it remains safely stored – even in the event of geological changes. “[These changes] such as an earthquake or anthropogenic activities, would no longer affect the situation. The CO2 is safely stored in the ground,” De Paoli explains.

Governments and industries have been racing to develop carbon capture technologies. What seemed like a precarious solution – pumping CO2 underground – now appears highly secure and effective, reinforcing carbon capture’s role as a vital strategy in our climate mitigation toolkit.