CSG leaks ‘equal to that of cows’

LEAKING methane from CSG wells was not as high as feared, with each well emitting about the same as four cows, a CSIRO study has found.

LEAKING methane from coal-seam gas wells was not as high as feared, with each well emitting about the same as four cows, a CSIRO study has found.

A review of 43 CSG well sites in Queensland and NSW undertaken for the federal environment department found leaking from the Australian industry was much lower than in the US.

All of the methane leaks were from equipment and none due to the release of gas from outside of the well casing. The worst leaks were from well sites that were under pressure after being put out of production.

The report found emission rates from production sites ranged from zero to a maximum of about 44g a minute.

Overall, the median methane emission rate from all sources for the wells examined was about 0.6g a minute while the mean emission rate was about 3.2g a minute, or about seven cubic ­metres a day.

“This compares to a mean production rate of the 43 wells of 29,600 cubic metres a day and represents about 0.02 per cent of total production,’’ the CSIRO report said. Given the relatively small number of wells tested, the CSIRO report recommended more testing as well as an assessment of other potential emission points in the gas production chain.

The CSIRO research was released as the federal government’s mandatory renewable energy target review considers a radical plan that could dramatically boost the role of gas in cutting the nation’s carbon emissions from electricity generation.

In a submission to the MRET review, the Australian Energy Market Commission has suggested a new scheme based on energy intensity. This would allow ­efficient gas and other low emissions generators to issue renewable energy certificates and compete with wind and solar to meet the nation’s renewable ­energy target.

AEMC makes and amends the rules for the National Electricity Market and elements of the gas markets. It is an independent body that provides advice to the Council of Australian Governments’ Energy Council.

A review panel headed by businessman Dick Warburton is expected to hand down its review of the RET this month.

As well as concerns about underground water contamination the carbon footprint of gas production due to fugitive methane emissions has been a key environmental question.

Fugitive emissions from unconventional gas production have been a major concern for environmental groups because methane is a much more potent and longer lasting greenhouse gas than carbon dioxide.

A paper published in the American Proceedings of Science last month found electricity generated using coal-seam gas or shale gas produced less than half the carbon dioxide emissions of electricity from burning coal.

But lead author Gavin Heath, from the National Renewable Energy Laboratory, said more work was needed to better understand the impact of fugitive emissions.

Results of the CSIRO study were welcomed by the Australian gas industry lobby group, APPEA.

It said the mean rate of fugitive emissions was the same as four cows. But anti-coal seam gas group Lock the Gate said the results of the CSIRO research were preliminary. “The results show that 40 of the 43 wells were still leaking,’’ the group’s spokesman, Drew Hutton, said.