The industry numbers lie: Coal mine methane emissions are worse than you think

The coal mining sector has almost tripled in size in Australia since 1990 and yet – according to the industry – fugitive emissions have somehow stayed flat. The reality is that they have grown exponentially, says a new report by global energy think tank Ember. 

The report points a finger at the rise of open cast mining and rules that allow mine owners to effectively guess their emissions — and potentially turn the reformed Safeguard Mechanism, a key part of Australia’s climate policy, into an environmentally expensive failure.

“It’s clear that we have an emissions reporting problem that needs fixing, the critical questions will be if the government is ready to reclaim our emissions reporting integrity, and by when,” said Ember coal mine methane advisor Christopher Wright.

The official numbers documented by Ember claim that coal mine production expanded by 170 per cent between 1990 and 2022 in Australia, but that fugitive emissions only grew by 0.17 per cent.

“When compared to the increase in coal production, the average (reported) fugitive emissions intensity per tonne of coal has decreased by 63 per cent between 1990 and 2022,” the report says.

A recent dip is attributed to unplanned underground mine closures, more open cut mining which is much more difficult to measure so owners rely more heavily on estimates, and changes in the way emissions are measured.

About 75 per cent of Australian coal mines now open cut, which is a problem for fugitive methane emissions because the bigger a surface mine gets, the deeper it goes and the more methane it releases — which is also much harder to capture.

Since 2011, coal mine owners have had an option to report an estimate of the fugitive emissions using a state emissions factor, an estimate based on state data rather than actual on-site measurements, or a mine-specific estimate by the owner. 

Indeed, Glencore, the owner of open cut coal mine Hail Creek, yesterday disputed a research paper suggesting that project’s fugitive methane emissions were as much as eight times higher than reported.

It said, among other reasons, the paper did not take into account the fact that it recently shifted to site-specific measurements. 

But both of these systems have been called into question over the past five years by global and local groups using actual, and sometimes real-time data from satellites, aeroplanes equipped with measuring devices, and even hand-held cameras.

This data is collectively showing much, much higher fugitive emissions levels than that reported by mine owners — such as that Hail Creek study — casting reasonable doubt that current official reports are wrong.

The Ember paper says site-specific estimates may be making the problem of under-reporting even worse, hiding as much as 10 million tonnes of fugitive methane emissions a year.  

In New South Wales (NSW), Ember found that fugitive emissions intensity from open cut mines is now reported as six times lower than the state based emissions factor, highlighting how badly the different accounting measures are serving Australia.

Last year, Ember assessed eight operating and two proposed coal mines and found the shift in accounting resulted in millions of tonnes of CO2-e reductions – not the increase that should have been expected.

More research from energy insights firm Reputex found the accounting shift allowed coal mine owners to cut reported fugitive methane emissions by 65 – 70 per cent. 

The weight of the evidence emerging around under-reporting has spurred a federal review into site-specific measurements, and the launch of a new Expert Panel on Fugitive Methane Emissions.

Not under control

Momentum has been building for Australia to get methane emissions under control and not just because it is a signatory to the 2022 Global Methane Pledge.

Methane is a potent greenhouse gas, some 80 times more powerful than CO2 over two decades.

Not knowing what a mine is actually emitting has major implications for a mine’s obligations under the reformed Safeguard Mechanism and for future trading outcomes as Europe’s Carbon Border Adjustment Mechanism puts increased scrutiny on emissions reporting.

The Safeguard Mechanism reforms in 2023 cap emissions of the around 220 largest mining, gas and industrial facilities, based on the emissions intensity of their operations. Every year through to 2030 these caps will decline by between 1 per cent and nearly 5 per cent.

The facilities can reduce emissions to meet the caps, or they can buy and surrender carbon credits. 

The simpler and ultimately cheaper way for coal mines, Wright says, is to reduce their emissions.

Coal emissions capture is possible

A report by IEEFA last year suggested pre-draining methane from an open-cast mine could capture anywhere between 20-80 per cent of fugitive emissions, an abatement could be done for a cost of $1/tonne of saleable coal.

Not could could capture methane be economically viable over time, but it doesn’t even need to change how a mine is run.

“You take an operating mine, and you basically add technology to that mine to deal with its methane emissions,” Wright said at a conference in NSW yesterday. 

“You don’t change the mining process. You don’t change anyone’s jobs. You effectively add a couple of jobs to deal with that methane and you bring down those emissions while you continue operating.” 

Anglo American has invested $100 million a year in pre-mine drainage across four steelmaking coal mines which has potentially mitigated up to 5.3 million tonnes of CO2-e compared to fugitive emissions levels in 2019. 

This reduction continued in 2024, but was bolstered by the closure of the Grosvenor mine, the Ember report said.

“[Angle American] started with 8.7 million tons of fugitive emissions – methane converted to CO2… They suck out a bunch of it, they burn a bunch of it,” Wright said. 

“When they go to flare methane leakage, they’re actually using a lot of it for their own power generation. And then they have the remaining emissions they just can’t capture. So Anglo American in Queensland for their three or four mines, were able to not only use their methane, turn it in from a problem to a solution, and use it to actually generate electricity for their mines as well.” 

But the “nuclear option” is a ventilation air methane (VAM) capture device, either a thermal oxidizer – basically a big oven – or a catalyzer which converts the methane. 

Illawarra’s West Cliff Mine reduced its methane emissions by 2 million tonnes of CO2-e between 2007 and 2017 using the world’s first commercial scale VAM-to-power project, designed by CSIRO.