Carbon Sequestration and Natural Hydrogen

CO₂ Mineralisation

Current projections show that it is likely that the world will surpass the global warming target of 1.5°C due to excessive CO₂ in the atmosphere. Reaching these climate targets will require rapid and sustained reduction in emissions, the capture and storage of hard to abate emissions, and the removal of atmospheric CO₂ (negative emissions) at large scales.

There are various methods for carbon dioxide storage ranging from natural solutions like tree planting and soil sequestration to engineered approaches such as direct air capture, ocean fertilization, and carbon mineralisation. Each method has distinct CO₂ storage capacities and average storage durations before being release back into the atmosphere.

Hardie Pacific is actively working to introduce carbon mineralisation to the southern hemisphere. Our Australian company, Carbozorb, has permit locations in New South Wales, while our Aotearoa New Zealand company, Weora, has permits throughout the country.

We collaborate with researchers from universities and industries that emit CO₂ and other harmful gases, such as fluorine. Together, we aim to prevent the release of these gases into the atmosphere and instead store them securely and permanently in mineral form.

Natural Hydrogen

Ultramafic rocks produce natural hydrogen (H₂) when metamorphosed in the presence of water, a process called serpentinisation. Although natural hydrogen exploration is still in its infancy, seeps are known to occur around the world, including within Weora and Carbozorb’s licence areas.

It is unlikely that hydrogen will be found in pressurised stagnant reservoirs, as with traditional with methane deposits, instead, natural hydrogen occurs more often as slow flowing accumulations. Hydrogen gas is being continually generated from the serpentisation of the ultramafic rocks and it flows along the natural fractures within the rock mass.  We are investigating the economic potential for natural hydrogen across the licence portfolio’s and whether engineered systems for in situ carbon mineralisation could commercially produce hydrogen.

How it works

Carbon mineralisation is the formation of solid, stable carbonate minerals through the reaction of CO₂ with rocks and minerals rich in magnesium, calcium, and iron. CO₂ reactive rocks and minerals include ultramafic rocks, mafic rocks, olivine, serpentine, and plagioclase. The CO₂ can be used in many forms for mineralisation, either as a gas, liquid, supercritical CO₂ or dissolved in water. This process results in carbonate minerals such as magnesite, calcite, dolomite and creates hydrogen gas.

Carbon mineralisation is a naturally occurring geological process and responsible sequestering 150 – 300 Mt of CO₂ annually. We plan to engineer the system to accelerate this natural process.

Carbon Mineralisation has the greatest potential storage capacity of all sequestration/storage methods and can theoretically mineralise all CO₂ that has been, or ever could be generated.

The biggest advantage of mineral carbonation over other sequestration methods is that the carbon cannot escape back to the atmosphere and can be stored for millions of years – no liability or ongoing monitoring.

The Carbozorb and Weora permit areas in NSW and NZ contain large areas of magnesium and iron rich ultramafic rocks which are well suited for Mineral Carbonation. The dunite rock in the Weora permit areas have the highest magnesium concentration of any ultramafic rocks in the world.

Methods

Carbon mineralisation can be accelerated using different methods:

• In situ mineralisation, where CO₂ is dissolved in water and then the mixture is injected through a drill hole into an underground reactive rock formation.
• Ex situ mineralisation, where rocks are crushed to increase the reactive surface area and then exposed to CO₂. This process occurs at surface level and has the potential to produce saleable by-products such as CO₂ neutral cement or plasterboard.
• Enhanced weathering, which involves spreading finely ground rocks or minerals over large areas, such as farmland, where they react with CO₂ and water to form stable carbonates.

Weora is evaluating all three methods of Carbon mineralisation across its portfolio of licence and resource areas.

CO₂ Sources

Carbon mineralization relies on appropriate rock formations and concentrated sources of CO₂. There are two primary methods for capturing CO₂, capturing it at the emission source or through direct atmospheric air capture. Carbon mineralisation is well-suited to both approaches. CO₂ can be transported to the site where mineralization occurs, enabling flexibility in the implementation of this process.