Study shows CO2 storage is a ‘secure climate mitigation tool’

New research shows that captured carbon dioxide (CO₂) can be stored safely for thousands of years by injecting the liquefied gas deep underground into the microscopic pore spaces of common rocks. The findings – published in Nature Communications¹ – increase confidence in the widespread roll-out of engineered carbon capture and storage (CCS), reports Scottish Carbon Capture & Storage (SCCS).

In the study, researchers from SCCS’s partner institutes, the Universities of Aberdeen and Edinburgh, compiled a worldwide database of information from natural CO₂ and methane accumulations and hydrocarbon industry experience – including engineered gas storage, decades of borehole injection, and laboratory experiments.

Computer simulations were used to combine all these factors and model storage of CO₂ for 10,000 years into the future. Previous research in this area had not fully accounted for the natural trapping of CO₂ in rock as microscopic bubbles, or the dissolving of CO₂ into the salty water already in the rocks.

The UN Paris Agreement has committed the world to limiting climate warming to well below 2°C from pre-industrial levels. This requires huge reductions in the amount of the greenhouse gas, CO₂, which is released to the atmosphere from industry, electricity generation, heating and transport. Capturing these emissions and ensuring that CO₂ can be safely trapped underground is crucial for the successful protection of the atmosphere, states SCCS.

Dr Juan Alcalde, who co-led the research at the University of Aberdeen says: ‘The security of CO₂ storage is an understandable concern for people, communities and governments. Our work shows that the storage of CO₂ necessary to help address climate change can be secure for many thousands of years.’

Dr Stephanie Flude who co-led the work at the University of Edinburgh said: ‘We selected the model inputs to be conservative but realistic. Importantly, our computer simulations, based on good-regulation practices, such as those used currently in the North Sea, retained more than 90% of the injected CO₂ after 10,000 years in 95% of the cases. The most probable outcome being at least 98% retention.’

1. Alcalde, J, Flude, S, Wilkinson, M, Johnson, G, Edlmann, K, Bond, C E, Scott, V, Gilfillan, S M V, Ogaya, X and Haszeldine, R S. ‘Estimating geological CO2 storage security to deliver on climate mitigation’, Nature Communications, 9, 2018.