CO₂ Mineralisation

Storage as a service

We take your captured CO₂ and turn it into rock, onshore and close to your plant, for a fraction of what conventional storage costs.

	Decahydron mineralisation	Offshore storage
Cost	A fraction of conventional storage, independently certified by EY	Among the most expensive links in the CCS chain
Transport	Short onshore pipeline or truck from the plant	Liquefaction, port terminal and shipping
Location	Onshore, at the emitter	Offshore, with liquefaction and shipping
Capacity	Gigatonne scale in ultramafic rock	Limited by the field, often tens of millions of tonnes
Water	None	Required for dissolution-based injection
What is left underground	Carbonate rock: nothing that can leak	A CO₂ plume to monitor under the EU CCS Directive

Our first commercial-scale pilot will store 150,000 tonnes of CO₂ from Holcim’s HERACLES cement plant in Greece.

What carbon costs emitters today Talk to us about storage

Why do we need to store carbon dioxide?

To achieve Net Zero climate targets, estimates suggest we will need to sequester 10 gigatons of CO₂ annually by 2050. While cutting emissions is essential, it is not enough. We also need to remove and store excess carbon, and carbon mineralisation is one of the most effective ways to do it.

What Is Carbon Mineralisation?

Carbon mineralisation is a natural process where CO₂ reacts with certain types of rock to form stable, solid minerals, locking carbon away for geological timeframes. Decahydron is developing technology to accelerate this process by injecting supercritical CO₂ into ultramafic rock, which is uniquely suited to absorb and mineralise carbon permanently.

Supercritical CO₂ is carbon dioxide held at a temperature and pressure high enough to behave like both a gas and a liquid.

Two saw-cut cubes of ophiolite rock: fresh and near-black on the left, browned and cut by white carbonate veins after CO₂ mineralisation on the right — Lab photoOphiolite rock before (left) and after (right) CO₂ mineralisation. The CO₂ has become white carbonate filling a network of veins.

IllustrationTime-lapse of the same cube: carbonate veins grow from the existing crack as the rock takes up CO₂.

What makes our approach different?

No water requiredConventional in-situ mineralisation uses around 50 tonnes of water for every tonne of CO₂. We inject CO₂ alone, so the process works even in water-stressed regions.

PermanentThe CO₂ becomes part of the rock as carbonate. There is nothing left to leak.

Close to the emittersUltramafic rock lies near cement plants, steel mills and power stations in the Gulf and in southern Europe.

Dense vs dissolved: how our technology compares

White carbonate crust in a stream bed between serpentinite boulders — Field photoCarbonate forming today where alkaline spring water meets the air, Fujairah.

Why Ultramafic Rock?

Ultramafic rock is rich in magnesium and iron, making it ideal for carbon mineralisation. When CO₂ interacts with it, a permanent transformation occurs: the carbon becomes part of the rock itself. No risk of leaks and no need for ongoing management, just safe, permanent CO₂ storage.

Serpentinite outcrop with a dense network of white carbonate veins — IllustrationSerpentinite with carbonate veins, the rock type of our Greek project.

And hydrogen out of the same rock

The reaction that locks CO₂ into stone can also release hydrogen. One reactor, carbon in and hydrogen out.

Hydrogen from CO₂

How do we know that CO₂ cannot escape?

Every injection site will be monitored with sensor networks, from the surface to the reservoir. This lets us verify permanent storage and meet the standards needed to issue high-quality carbon credits.

A seismic survey truck in the desert below ophiolite mountains — Seismic surveys image the reservoir before, during and after injection.

Which industries will use CO₂ mineralisation?

In the near term, we will take CO₂ from hard-to-abate industries including cement, steel and chemicals. In Greece our project will mineralise CO₂ captured at a Holcim cement plant. As direct air capture and other removal technologies scale, we will also be able to mineralise CO₂ pulled straight from the atmosphere.

See the PITHOS project