Geoenvironmental engineering aspects of carbon capture, utilisation, and storage

The unprecedented carbon dioxide (CO₂) concentrations in the atmosphere, followed by a global surface temperature increase above pre-industrial levels during 2011–2020, of about 1.1°C (over land 1.59°C), have put an urgency on the UN goal of attaining net zero emissions by 2050. Until the transition to clean energy sources is attained, carbon dioxide capture, utilisation, and storage (CCUS) remain a near-term, high-priority mitigation measure to control carbon dioxide emissions from fossil-fuel-based processes. The present article contributes to the topic of CCUS by assessing, initially, the maturity for industrial-level application of current carbon dioxide capture technologies. Subsequently, the advantages and limitations of geoenvironmental applications of carbon dioxide in the neutralisation of industrial by-products are detailed, as well as the use of carbon dioxide as a working fluid for geothermal heat extraction from abandoned oil and gas wells. The challenges of subsurface formation characteristics for the storage of carbon dioxide, with emphasis on geomechanical behaviour, are discussed. Injection of carbon dioxide into hydrate sediments constitutes another carbon dioxide storage option that can also allow the use of methane as an energy source. Finally, the paper analyses the liability issues of carbon storage projects and the challenge of assessing long-term risks to provide insurance coverage to them.