Water could be key to carbon capture

Scientists claim they have managed to lock CO2 in underground water in gas fields around the world where it will remain for millions of years, marking a major step forward in developing viable carbon capture and storage technologies.

The international team from the universities of Manchester, Edinburgh and Toronto say they have overcome concerns that this kind of long-term storage might not work and quelled doubts that the gas might be securely trapped.

Project director Professor Chris Ballentine, from the University of Manchester’s School of Earth, Atmospheric and Environmental Sciences, said: “We cannot change our society overnight to a low carbon economy. While we are in this transition we have to bury our excess CO2 emissions.

“Developing a clear understanding of how natural systems behave means that when we inject CO2 into similar systems we know exactly where it will go. This verification is essential to provide public confidence in the safety of this disposal technology.”

In the natural world carbon dioxide is trapped underground either by dissolving into water to create sparkling mineral water or by reacting with certain kinds of rock to create limestone and similar minerals.

Until now, research into CCS has relied largely on computer modelling but this study has taken a more practical approach to find out how naturally-occuring carbon is stored.

“We’ve turned the old technique of using computer models on its head and looked at natural carbon dioxide gas fields which have trapped carbon dioxide for a very long time,” said Dr Stuart Gilfillan, from the University of Edinburgh.

“By combining two techniques, we’ve been able to identify exactly where the carbon dioxide is being stored for the first time.

“We already know that oil and gas have been stored safely in oil and gas fields over millions of years.

“Our study clearly shows that the carbon dioxide has been stored naturally and safely in underground water in these fields.”

Sam Bond

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