Storing CO2 underground may be a safe solution to mitigate climate change, according to a IDAEA-CSIC study
31 January 2023
A study led by the Institute of Environmental Assessment and Water Research (IDAEA) and the Mediterranean Institute for Advanced Studies (IMEDEA CSIC-UIB), both belonging to the Spanish National Research Council (CSIC), has shown that injecting billions of tonnes of atmospheric CO2 (carbon dioxide) underground has a low risk of leakage back to the surface. According to the simulations, the CO2 would remain deep in the subsurface for millions of years, even if the overlying low-permeability rocks were fractured. These results indicate that this technology, called geological CO2 storage, can be safely undertaken to mitigate climate change.
The study, published in the journal Geophysical Research Letters, has been carried out in collaboration with the Lawrence Berkeley National Laboratory and the University of Illinois at Urbana-Champaign. This interdisciplinary research has developed a novel methodology to calculate the probability of CO2 leakage considering billions of tons of CO2 injected underground over a time scale of millions of years, much larger than what had been investigated until now.
The objective of CO2 storage is to take this greenhouse gas from the hard-to-abate industry and inject it deep underground. For the gas to remain at depth, it must be injected into rocks with high permeability and porosity, such as sandstones. However, there is a risk of CO2 leakage, as CO2 is less dense than the saline water that fills the pores at great depth, so it can float upwards and leak back to the surface”, explains the IDAEA-CSIC researcher Iman Rahimzadeh Kivi and first author of the study.
Kivi, I.R., Makhnenko, R.Y., Oldenburg, C.M., Rutqvist, J. and Vilarrasa, V., 2022. Multi-layered systems for permanent geologic storage of CO2 at the gigatonne scale. Geophysical Research Letters, 49 (24) e2022GL100443. DOI: 10.1029/2022GL10044