The potential of Carbon Capture and Storage as a support to the international efforts to reverse the CO2 concentration increasing trend.
By Enrico Chiogna | YPA Italy
During the opening ceremony of the COP26 World Leader’s Summit in Glasgow, among the speeches of the global leaders, the statement of David Attenborough – famous British science communicator and author of countless nature documentaries – was particularly strong.
While his familiar voice was accompanied by devastating images of climate change effects, Attenborough pointed out that the main driver of the emergency crisis can be summed up in a number: 414.
This number corresponds to the present value of atmospheric concentration of CO2 measured in ppm (parts per million): this has grown exponentially in the last 250 years, since the beginning of the industrial revolution and the massive exploitation of fossil fuels for energy production.
The capability of CO2 to trap infrared radiation emitted from the Earth surface inside the atmosphere – generating the so-called greenhouse effect – is well known. Similarly, it is also well known that anthropogenically-induced global warming generates a range of catastrophic consequences for human society, from increased frequency and intensity of extreme weather events to melting ice and rising sea levels. Higher CO2 concentrations are also fostering the acidification of the oceans, making them more and more inhospitable to the survival of the delicate marine ecosystems.It is crystal-clear that the trend of CO2 atmospheric concentration must be reversed to reduce the adverse effects of climate change.
Drastic actions are needed, but, despite the constant efforts going on within the COP, the achievement of 2015 Paris Agreements targets is still a long way off. In this sense, the most important issue concerns the transition from an economy based on fossil energy sources to one based on renewable energy sources, such as solar photovoltaic, wind, hydroelectric, geothermal and nuclear. While the Emission Gap Report 2021 shows the inadequacy of national plans for CO2 emission reduction (operationalised in the Nationally Determined Contributions), experts point to the technical complexities in decarbonising some industrial sectors, including the chemical, steel and long-distance transport industries.
In this daunting context, in which pursuing economic decarbonisation remains a priority, it is necessary to maintain a strong focus also on Carbon Capture and Storage (CCS) methods. These essentially focus on two approaches.
On the one hand, enhancing the CO2 absorbing capacity of natural carbon sinks: the Earth system is a complex system and anthropogenic emissions of CO2 are offset by oceans and forests, which are able to absorb about half of the CO2 emitted into the atmosphere. This can be done especially for forests, which are threatened by deforestation, through programmes such as the United Nations REDD+ (Reducing Emissions from Deforestation and forest Degradation) programme, to which the 53 States of the Coalition for Rainforest Nations (CfRN) belong.
On the other hand, CCS technological solutions have gained ground in recent years, among which Direct Air Capture (DAC) being the most relevant. DAC is based on capturing CO2 directly from the atmosphere by means of huge fans equipped with sophisticated chemical filters that allow CO2 to be deposited in liquid or solid form. CO2 can then be stored permanently underground, so that it settles in solid form, or it can be used to produce carbon neutral fuels – fuels with zero CO2 net emissions – or other commercial uses (for example, surprisingly, the production of carbonated soft drinks).
At present, DAC technology is still quite immature but, given its possible role in reversing the CO2 trend, several studies are investigating its potential and implications. Doubts persist about the stability of CO2 deposits, as well as about the controversial nature of their commercial exploitation, as DAC technology is currently attracting investments mainly for Enhanced Oil Recovery (EOR) applications, that is, a methodology for extracting more hydrocarbons from depleted deposits.
A piece of good news is that Climeworks, a Switzerland-based company, has completed – in partnership with Carbfix – the construction of the first large-scale commercial DAC plant: ORCA, launched in 2021 near Hellisheidi, Iceland. Climeworks is committed by statute to use the captured CO2 in an ecologically sustainable way, avoiding selling it to large oil holding companies. The hope is that Climeworks will take a leadership role among companies entering this emerging market, spreading its ethical and ecological commitments.
CCS is not a panacea for carbon trend reversal, but it has the potential to support speeding up the achievement of the net-zero goal and finally stabilise the CO2 concentration in the atmosphere, before moving, hopefully, to a new phase of negative emissions and decreasing CO2 concentrations. However, repetita iuvant, it is still crucial that the COP26 delegates reach substantial agreements on intermediate and binding emission reduction targets, avoiding to appeal to future CO2 reductions guaranteed by CCS in the umpteenth attempt to postpone these targets.