Fault Lines No Barrier to Safe CO2 Storage

Carbon dioxide emissions can be captured and securely stored in underground rocks, even if geological faults are present, research has confirmed.

There is minimal possibility of the gas escaping from fault lines back into the atmosphere, a study has shown.

The latest findings, from tests on a naturally occurring CO2 reservoir, may address public concerns over the proposed long-term storage of carbon dioxide in depleted gas and oil fields.

Scientists from the Universities of Edinburgh, Freiburg, Glasgow and Heidelberg studied a natural CO2 repository in Arizona, US, where gas migrates through geological faults to the surface.

Researchers used chemical analysis to calculate the amount of gas that had escaped the underground store over almost half a million years.

They found that a very small amount of carbon dioxide escaped the site each year, well within the safe levels needed for effective storage.

The study, published in Scientific Reports, was supported by the European Union and Natural Environment Research Council.

"This shows that even sites with geological faults are robust, effective stores for CO2," said Dr Stuart Gilfillan, School of GeoSciences, University of Edinburgh. "This find significantly increases the number of sites around the world that may be suited to storage of this harmful greenhouse gas."