Emissions accounting variability

This report examines the discrepancy between satellite-observed methane emissions and company-led estimates from open-cut coal mines in Australia, specifically focusing on the impact of shifting from state-based (Method 1) to site-specific (Method 2) emissions accounting in New South Wales.

• Open-cut coal mines in Australia do not directly measure fugitive methane emissions, instead relying on models. Method 1 uses state-based emissions factors developed in 1991 and 1993 for New South Wales and Queensland. Method 2, introduced in 2011, allows companies to use site-specific 3D models based on as few as three borehole samples.
• The adoption of site-specific emissions estimates (Method 2) has led to a significant decrease in officially reported emissions. Research from Reputex indicates that this shift has consistently reduced reported fugitive methane emissions by 65–70%.
• There is a stark difference in the adoption of Method 2 between New South Wales and Queensland as of 2023. In New South Wales, where the state-based emissions factor was 0.061 t CO2-e/t ROM, 75% of open-cut coal mine methane emissions used Method 2. In Queensland, where the factor rose from 0.023 to 0.031 t CO2-e/t ROM, only 25% used Method 2.
• Satellite analysis of New South Wales coal production (covering 60% to 64% of production) found fugitive emissions that were 90% greater in 2020 and 107% higher in 2021 than reported emissions. These satellite estimates correlate more closely with a reconstruction of emissions using the state-based Method 1.
• Method 2 is now mandatory for open-cut mines under the Safeguard Mechanism producing over 10 million tonnes per year and will be the industry standard for all Safeguard reporting coal mines by 2026. A federal review is currently underway to determine if the method is still fit for purpose, with a conclusion expected later in 2025.

APA

Ember (2025). Emissions accounting variability. https://ember-energy.org/chapter/emissions-accounting-variability/

Chicago

Ember. Emissions accounting variability. 2025. https://ember-energy.org/chapter/emissions-accounting-variability/.

Wikipedia

{{cite report |author=Ember |title=Emissions accounting variability |date=16 April 2025 |url=https://ember-energy.org/chapter/emissions-accounting-variability/ |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{ember2025emissions, author = {{Ember}}, title = {{Emissions accounting variability}}, institution = {Ember}, year = {2025}, month = apr, url = {https://ember-energy.org/chapter/emissions-accounting-variability/}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }