New study helps identify criteria for effective greenhouse gas emissions storage

A study on natural underground reservoirs of carbon dioxide (CO₂) has revealed major reasons to store man-made greenhouse gas emissions effectively.

Conducted by the scientists of Scotland’s University of Edinburgh and the University of Strathclyde, the research will inform development of a new Carbon Capture and Storage (CCS) technology, which will help hold CO₂ from power stations deep underground and prevent emissions from contributing adversely to climate change.

The University of Edinburgh’s School of GeoSciences’ lead researcher of the study Dr Johannes Miocic said: "Lessons for safe CO₂ storage can be learned from nature, which has been containing greenhouse gas securely for millennia."

The discoveries made by the researchers add to the evidence showing this storage approach is secure in the long-term, leading to the selection and design of future sites.

The University of Edinburgh’s School of GeoSciences’ study co-ordinator Dr Stuart Gilfillan said: "This study confirms that our current approach to creating CO₂ stores is effective and will help ensure future CCS sites are safe and secure."

Researchers from the universities evaluated data on 76 natural reservoirs in Asia, America, Australia, and Europe. Being more than a million years old, these gas pools were formed due to geological changes, volcanic eruptions, or from decayed plants and animals.

The researchers have also identified geological conditions, such as pressure, optimum temperature, and types of rock, which are best suited for long-term CO₂ storage. Sites deeper than 1200m with a high density of gas and multiple thick cap rocks all prove to be beneficial.

The researchers have also revealed that the major cause of leaks was due to the movement of gas through geological faults. Leaks of CO₂ would result in gas emissions, posing a serious health risk and undermining public confidence in CCS technology.