A comprehensive review of enhanced in-situ CO2 mineralisation in Australia and New Zealand

Abstract

The urgent need to accelerate permanent anthropogenic carbon dioxide (CO2) abatement has led to a growing interest in in-situ CO2 mineralisation globally. This review outlines the progress of in-situ CO2 mineralisation in Australia and New Zealand, while focusing on potential sink reservoirs for mineralisation, including magnesium-rich and calcium-rich ultramafic and mafic rocks. These rock types are abundant in various regions across both countries. The review first begins by highlighting the current status and progress of Australian and New Zealand emissions and national abatement goals. It then previews the currently funded carbon capture, utilisation, and storage (CCUS) projects across both countries and discusses where in-situ CO2 mineralisation stands to complement other CO2 storage methods. Secondly, it details the different mineralisation mechanisms within selected rock types/complexes in Australia and New Zealand, followed by a discussion of the limitations and advantages of each selected major rock type/complex within both countries, including the relative distances between deposits and major emission hotspots. Finally, within this review we examine the governmental funding and perception of enhanced in-situ CO2 mineralisation within the two countries. An example in Mount Keith Ultramafic Complex (MKUC) is also presented, which shows the relationship between rock permeability, expected CO2 injection, and the estimated cost per ton for direct pumping into low permeability Peridotite deposits. The results show an inversely proportional relationship between permeability and injection rate, and thus the cost per ton of CO2 stored.The estimated cost calculations clearly demonstrate that the limiting factor of in-situ mineralisation is not the availability of sink reservoirs within Australia and New Zealand but rather the need for significant government incentives to present an attractive breakeven cost that can compete in the CO2 storage market. The results also show that New Zealand currently has a slight advantage due to the 2-fold higher carbon pricing compared to Australia.