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SCU scientists publish first peer-reviewed paper on Australian CSG methane emissions


Brigid Veale
18 November 2014
Research by Southern Cross University scientists has led to the first peer-reviewed paper on atmospheric methane and carbon dioxide concentrations in Australian coal seam gas (CSG) fields, published in the international journal Water, Air and Soil Pollution.

The paper’s authors are Dr Damien Maher, Professor Isaac Santos and Dr Douglas Tait from the Centre for Coastal Biogeochemistry Research in the School of Environment, Science and Engineering, who first presented the preliminary research findings of their study at a public seminar in Lismore in November 2012.

The paper titled ‘Mapping methane and carbon dioxide concentrations and δ13C values in the atmosphere of two Australian coal seam gas fields’, has been published in Water, Air and Soil Pollution, an international, interdisciplinary journal on all aspects of pollution and solutions to pollution in the biosphere. It follows another peer-reviewed paper, published in the international scientific journal Environmental Science and Technology in April 2013, which found a link between concentrations of radon gas in CSG fields and the number of CSG wells nearby.

The researchers used novel instrumentation to map atmospheric methane and carbon dioxide concentrations in and around coal seam gas fields in the Darling Downs and northern New South Wales.

“CSG is often assumed to be a cleaner fuel than coal in terms of greenhouse gas footprint,” said Professor Santos.

“However, if methane is being lost to the atmosphere during the extraction, processing and transportation processes, this assumption may not be valid.
“This is due to the potency of methane as a greenhouse gas, which is about 100 times more powerful than carbon dioxide over a 20-year time frame.”

Dr Tait said they found consistently elevated methane and carbon dioxide concentrations within the CSG fields of the Darling Downs.

“This study clearly showed that there is something going on in these areas leading to increased atmospheric greenhouse gas concentrations.”

One of the major issues with attributing the elevated gas concentrations to coal seam gas mining is the lack of baseline studies.

“From our data we cannot conclusively say that the elevated concentrations are due to CSG mining activities as we have no information about the area before the commencement of CSG mining,” said Professor Santos.

However, the study’s lead author, Dr Damien Maher said there were some clues as to where the methane and carbon dioxide was coming from.

“The technology we used gives us additional information about the methane and carbon dioxide,” Dr Maher said.

“We also measure the carbon stable isotope ratios of the gases, which is like a chemical fingerprint. This gives us insight into where the gases came from and how they were formed.

“This is a very powerful tool which enables us to model what the source of these gases might be, which is important in areas where there are a number of potential sources. For example in the Darling Downs the methane and carbon dioxide can be coming from sources other than CSG such as wetlands, feedlots and vehicles.

“The methane in the atmosphere of the Darling Downs gas field has a very similar fingerprint to methane in the CSG of the region.

“A portion of the carbon dioxide appears to be coming from the expansive water holding ponds, which was something that surprised us.”

The researchers agree this is only a first step in determining the greenhouse gas footprint of the CSG industry in Australia

“While we know that there are some leakages happening in the studied CSG field, we do not know the magnitude of these leakages, nor do we know if this is a consistent trend across all CSG fields in Australia, these are areas of research we are actively pursuing,” said Dr Tait.

This research was made possible through instrumentation funded through an Australian Research Council grant.

Photo: Professor Isaac Santos and Dr Damien Maher, from the Centre for Coastal Biogeochemistry Research.