Carbon Capture Technologies

AThe accelerating pace of climate change has prompted scientists and policymakers alike to explore a range of mitigation strategies, among which carbon capture and storage — commonly abbreviated as CCS — has emerged as a particularly significant intervention. Carbon capture refers to the process by which carbon dioxide is removed from either industrial emissions or directly from the atmosphere, subsequently stored in geological formations deep beneath the Earth's surface. Given that global temperatures have already risen by approximately 1.2 degrees Celsius above pre-industrial levels, many researchers argue that conventional emissions reductions alone will be insufficient to meet internationally agreed climate targets. Consequently, CCS has been positioned not merely as a supplementary tool but as a potentially indispensable component of any credible decarbonisation strategy. It appears, therefore, that the role of carbon capture will only grow in urgency as climate commitments tighten.

BThere are currently two principal categories of carbon capture technology, each distinguished by the point at which carbon dioxide is intercepted. The first, known as point-source capture, involves extracting CO₂ directly from large industrial facilities such as power stations, cement plants, and steel foundries before it enters the atmosphere. This approach has been commercially deployed at a small number of sites worldwide and is generally considered more technically mature than its counterpart. The second category, direct air capture — or DAC — operates by drawing ambient air through chemical filters that bind to CO₂ molecules, which are then separated and compressed for storage. In contrast to point-source methods, DAC may be installed virtually anywhere, offering considerable geographical flexibility. Nevertheless, both approaches share the fundamental challenge of achieving carbon capture at a scale sufficient to produce measurable climate benefits.

CThe geological storage of captured carbon dioxide represents another critical dimension of the CCS process and has attracted considerable scientific scrutiny. Once compressed into a supercritical state — a phase in which the substance exhibits properties of both liquid and gas — CO₂ is typically injected into porous rock formations located between 800 and 3,000 metres underground. Saline aquifers and depleted oil and gas reservoirs have been identified as the most viable storage sites, given their demonstrated capacity and structural integrity. Long-term monitoring programmes suggest that, under appropriate geological conditions, stored CO₂ is unlikely to migrate or leak over human timescales. Furthermore, mineralisation — the process by which CO₂ gradually reacts with surrounding rock to form stable carbonate minerals — could provide an additional layer of permanence to underground storage, effectively converting gaseous carbon into solid rock over centuries.

DDespite the considerable promise that CCS technologies have demonstrated, a number of significant economic and logistical obstacles have prevented their widespread deployment. The capital costs associated with constructing capture facilities remain prohibitively high, and the energy penalty — the additional fuel consumption required to operate capture systems — currently reduces the overall efficiency of power generation by an estimated 15 to 25 percent. Critics have further argued that investing heavily in CCS risks creating a moral hazard, potentially discouraging the transition to renewable energy sources by implying that fossil fuel use may continue indefinitely with impunity. This counter-argument carries considerable weight and ought not to be dismissed lightly. Nevertheless, proponents maintain that CCS and renewable energy are not mutually exclusive but rather complementary technologies that could operate in parallel during the complex, multi-decadal transition away from carbon-intensive economies.

ELooking ahead, the future trajectory of carbon capture will depend substantially on policy support, technological innovation, and international cooperation. Several governments have introduced carbon pricing mechanisms and tax incentives that are beginning to improve the economic viability of CCS projects. Meanwhile, emerging technologies such as bioenergy with carbon capture and storage — known as BECCS — could theoretically produce negative net emissions by combining biomass combustion with carbon sequestration. If these technological and regulatory conditions were to align effectively, it is conceivable that atmospheric CO₂ concentrations could be stabilised or even reduced within the latter half of this century. The scientific consensus suggests that, without substantial investment in carbon capture alongside aggressive emissions reductions, achieving the targets set by the Paris Agreement would become extraordinarily difficult.