New research shows that for millions of years carbon dioxide has been stored safely and naturally in underground water in gas fields saturated with the greenhouse gas. The findings - published in Nature yesterday - bring carbon capture and storage a step closer.
Chaffin Ranch geyser, Utah - this geyser erupts from an aquifer naturally saturated with carbon dioxide (picture from www.nerc.ac.uk)
In research funded by the Natural Environment Research Council (NERC) and the Natural Sciences & Engineering Research Council of Canada, scientists from the University of Manchester measured the ratios of isotopes of carbon dioxide and noble gases like helium and neon in nine gas fields in North America, China and Europe. These gas fields were naturally filled with carbon dioxide thousands or millions of years ago.
They found that underground water is the major carbon dioxide sink in these gas fields and has been for millions of years.
Dr Stuart Gilfillan, the lead researcher who completed the project at the University of Edinburgh said, "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.
"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."
Professor Chris Ballentine of the University of Manchester, the project director, said, "The universities of Manchester and Toronto are international leaders in different aspects of gas tracing. By combining our expertise we have been able to invent a new way of looking at carbon dioxide fields. This new approach will also be essential for monitoring and tracing where carbon dioxide captured from coal-fired power stations goes when we inject it underground this is critical for future safety verification."
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