CARBON CAPTURE AND UTILIZATION

Carbon emission and its consequent effect on global warming and climate change have generated waves of conversation throughout the world [1]; there is renewed commitment to forestall rise in average global temperature so as to ensure environmental sustainability. Amongst the different mitigation technologies that have been identified by recognised bodies and organisations such as Intergovernmental Panel on Climate Change (IPCC), International Energy Agency (IEA), Global Institute for Carbon Capture and Storage etc, Carbon Capture and Storage (CCS) has been highlighted as one of the cost effective mitigation/decarbonisation technologies that would ensure Paris Agreement of 2015 is met and global temperature is limited to 1.5^oC rise.  With a capacity to sequester carbon from process systems (in chemical sector, CCS can has capacity to capture 14 GtCO₂ by 2060 [2]), CCS has received a lot of attention from policy makers and relevant authorities in recent times. This has resulted in deployment of 19 CCS facilities globally with 32 at various stages of construction [3].

However, CCS is cost intensive thereby presenting a challenge to its construction hence; strategies to make to CCS economically attractive have become a hot area of research; one of such area is Carbon Capture and Utilization (CCU). In CCU processes, the “captured” CO₂ is either converted to technological fluids such as chemicals or fuels or to inorganic carbonates through mineralisation as shown in Fig. 1 thereby facilitating development of circular economy; therefore, CCU can be considered as carbon negative, neutral or reducing. The economic possibilities provided by this processes incentivizes deployment of CCS industry. For instance, CCU can generated a revenue stream of 8.8 – 1.0 trillion dollars if as low as 10% of CO₂ emitted annually is captured and converted to high valued products.

 

Fig. 1. CO₂ lifecycle and utilisation pathways, dashed lines separates technosphere and ecosphere (source:[4])

Despite the positive effects of CCU, the technology is underdeveloped and under-utilized. This is corroborated by data which highlights that CCU market consumes 300 MtCO₂ as compared to 14000 MtCO₂ emitted annually. Nonetheless, it is critical to highlight the high CO₂ storage retention time needed to facilitate forestalling of increase in carbon emission into the atmosphere; this challenges efficacy of CCU for reduction of atmospheric CO₂ concentration. A research carried out by Lindeberg in 2003 which was published in Greenhouse Gas Control Technologies, Elsevier highlights that carbon needs to be stored away from the atmosphere for a minimum of 7200 years so as to have significant impact on carbon emission reduction; this therefore posits CCU as a means of incentivizing CCS not necessarily a CO₂ sequestration strategy.

Conclusively, CCU is a viable option that can support deployment of CCS in capacities that can limit global warming to 1.5^oC rise. In other words, CCU has the capacity to support deployment of high number of CCS facilities (~2500 CCS plants) needed globally to reduce carbon emission for environmental sustainability.

REFERENCES

[1]         V.J. Aimikhe, O.E. Eyankware, Adsorbents for Noxious Gas Sequestration: State of the Art, J. Sci. Res. Reports. 25 (2019) 1–21. doi:10.9734/JSRR/2019/v25i1-230176.

[2]         IEA, Transforming Industry through CCUS, Paris, 2019.

[3]         Global CCS Institute, Global Status of CCS 2019: Targeting Climate Change, Melbourne, 2019.

[4]         M. Bui, C.S. Adjiman, A. Bardow, E.J. Anthony, A. Boston, S. Brown, P.S. Fennell, S. Fuss, A. Galindo, L.A. Hackett, J.P. Hallett, H.J. Herzog, G. Jackson, J. Kemper, S. Krevor, G.C. Maitland, M. Matuszewski, I.S. Metcalfe, C. Petit, G. Puxty, J. Reimer, D.M. Reiner, E.S. Rubin, S.A. Scott, N. Shah, B. Smit, J.P.M. Trusler, P. Webley, J. Wilcox, N. Mac Dowell, Carbon capture and storage (CCS): The way forward, Energy Environ. Sci. 11 (2018) 1062–1176. doi:10.1039/c7ee02342a.