Posted
Photo:
Australia could fail to meet its Paris climate commitments due to unmeasured methane leaks. (ABC News: Scott Kyle)
A scientific report looking at bubbling methane
emissions in a Queensland river has found that the release of such gases
could rise significantly with continued coal seam gas (CSG) operations.
Key points:
- CSG extraction could increase uncontrolled gas releases, report says
- Methane is one of the most potent greenhouse gases
- CSG not yet proven to be cleaner than coal, say report authors
The ABC last year reported landholder concerns about intensifying methane emissions from the Condamine River near Chinchilla, which led to dramatic pictures of it being set alight by NSW Greens MP Jeremy Buckingham.
In a report to be released today, the University of Melbourne Energy Institute states the continued depressurisation of coal seams, combined with groundwater extraction by industry and landholders, "could significantly increase gas releases from weak or porous zones such as the Condamine River" in southern Queensland.
Methane is one of the most potent greenhouse gases.
The Energy Institute has warned that unmeasured methane leaks from unconventional gas fields could cause Australia to fail its Paris climate commitments.
Its new report, commissioned by the Australia Institute, reviews current scientific literature to assess the risk of so-called migratory or fugitive emissions resulting from rapidly expanding CSG development in Queensland.
Report co-author and geophysicist Dimitri Lafleur said data from CSG producer Origin Energy showed the amount of methane released through bubbling in the Condamine River quadrupled between 2013 and 2016, before declining.
"CSG is one of the actors and it's an actor that has increased activity quite recently, so there is certainly a correlation," Melbourne University's chair of geology Mike Sandiford, the report's other author, told the ABC.
But the authors found a "paucity of data makes it impossible to definitively assess the impact" CSG production may have had on creating unintended gas leaks.
Gas seeps can occur naturally and contributory factors can include drought and flood cycles and an area's geology.
Methane emissions in river have fallen, says Origin
In a statement to the ABC, Origin Energy said it had new data which showed methane emissions from the Condamine River had fallen significantly.
"Our data and CSIRO flux measurements show that peak rates of late 2015 to early 2016 have reduced substantially and we recently saw the lowest measurement since recordings began in 2013 — a reduction of over 60 per cent in the last six months," it said.
"We have been monitoring the Condamine River seeps since they were first observed to have increased in 2012 and continue to work with independent researchers including the CSIRO to better understand the local geology and possible causes," it said.
Professor Sandiford welcomed Origin Energy's monitoring efforts and news of the decrease in methane emissions from the Condamine River, but said a much greater understanding of the long-term effects of sub-surface activity was needed.
Jury still out on whether CSG is clean, report authors say
CSG is "a relatively new technology for extracting gas from the subsurface" which "has rarely been done at the scale that it has been done in Queensland," Professor Sandiford cautioned."One of the problems, of course, is migratory emissions may continue for many, many years after the production is started," he said, pointing to the current national debate about the role of gas in Australia's energy future.
"[Natural] gas may be a very effective and useful transition fuel, but if it is releasing large amounts of [methane] emissions it will not be that, so we need to understand that," Professor Sandiford said.
"The argument is that natural gas is emitting half the carbon dioxide as coal, but that's not taking into account [all] the associated methane emissions," said co-author Mr Lafleur, who worked in the oil and gas industry in the Netherlands and Australia for more than a decade.
Landholders concerned about water supplies
The Melbourne Energy Institute report noted methane had been found to pose "a safety hazard, compromises water quality, can damage pumps and impacts the yield" of affected water bores.It said "the integrity of dedicated gas wells and other existing bores that were not designed to prevent migratory emissions is an area of concern" and the geology of the Condamine aquifer "increases the risk of migratory emissions occurring".
Queensland rural producer group AgForce said it has had an increase in the number of complaints from farmers over the past two years about methane affecting water supplies.
Helen Bender, whose family owns two properties near the Condamine River at Chinchilla, said they had lost three water bores due to increased methane levels.
"The methane emissions were so high … they were decommissioned … capped and sealed," she said, adding that hundreds of water bores in the Surat Basin had been affected by gas.
But Queensland's Department of Natural Resources and Mines told the ABC there was no evidence of the gas seeps causing any harm.
"Investigations to date, including an independent scientific panel review coordinated by Queensland's chief scientist, support no evidence of environmental harm or public safety risk attributable to the gas seeps," it said in a statement.
Holistic plan needed to safeguard water, report says
"Sustainable and well-managed extraction of commodities such as water and fossil fuels from sedimentary basins requires a holistic sedimentary basin management plan," the report said."In the Queensland CSG-producing areas, there seems to be no clear understanding of the potential impacts of current and future human activities on the various aquifers," it said.Professor Sandiford said it is vital to understand the interaction of all subsurface activities such as the use of groundwater for agriculture, the mining for oil and gas, and any future underground carbon storage.
"It behoves industry, it behoves government, it behoves community groups to try and come together to better understand that system," he said.
No comments:
Post a Comment