By David Wroe
COAL seam gas, widely touted as a greener fuel than coal, could have just as deep a carbon footprint unless world-class standards are used when extracting the gas from the ground, an expert report has found.
A study into the life-cycle greenhouse emissions of Australia's energy sources by consultancy WorleyParsons found conventional gas from large offshore wells typically produced 38 per cent less greenhouse emissions than black coal, largely because it burnt more cleanly.
But the equation could shift dramatically for the fledgling coal seam gas industry - the subject of a fierce political battle in NSW and Queensland - if meticulous standards were not followed when the gas was extracted from the ground.
So-called ''fugitive emissions'', particularly of methane, which is a much more powerful greenhouse gas than carbon dioxide, can tip the balance and make coal seam gas as dirty a fuel source as black coal burnt in ageing power plants, the report says.
''If methane leakage approaches the elevated levels recently reported in some US gas fields … the [greenhouse gas] intensity of CSG … generation is on a par with sub-critical coal-fired generation,'' the report states.
The lead author, Paul Hardisty, said in a statement: ''The implications for regulators and the emerging Australian CSG industry are that best practice applied to design, construction and operation of projects can significantly reduce emissions, lower financial liabilities under the carbon tax, and help make CSG a less GHG-intensive fuel option.''
The report comes ahead of the introduction of the carbon tax on July 1, amid a battle between green groups and the energy sector over how to shift Australia to a cleaner energy mix. Many environmentalists argue that gas is little cleaner than coal and urge governments to encourage a quicker switch to renewables such as solar and wind energy.
But many in the energy sector argue a swift transition to renewables is unrealistic and gas - including coal seam gas - is needed as a stepping stone.
Alan Randall, professor of agricultural and resource economics at the University of Sydney, said the report showed Australia needed to tread carefully in the expansion of the gas industry.
''It seems like the more complete the research is, the more we tend to move away from the idea that the gas from CSG has big advantages over coal and may have a negative rather than a positive impact when all these things are considered,'' Professor Randall said. ''That's the big picture.''
The Australian Petroleum Production and Exploration Association, the chief lobby group for CSG, said the looming price on carbon would ultimately prove whether CSG was green-friendly.
''In the end, whatever their relative greenhouse intensities, all energy sources will be required to pay for their emissions under the carbon pricing legislation,'' a spokesman said.
''Over time, the pricing mechanism will naturally favour lower emissions technologies. That is its purpose.''
The new paper, which was published yesterday in the journal Energies, stated that high losses of CSG through leaks and venting were ''considered unlikely''.
But it said there were no Australian guidelines in place for estimating the natural gas fugitives.
It urged the industry to ''improve monitoring of methane releases and to adopt best practice technology and systems to reduce leaks and venting emissions''.
The Australian Coal Association chief executive, Nikki Williams, said the research highlighted the importance of carbon capture and storage to cut emissions.