Australia's New South Wales (NSW) state government is considering formulating rules to cut scope 1 greenhouse gas emissions at coal mines by reducing underground methane emissions and requiring mines to move away from diesel machines.

The rules may cover mines that emit over 25,000 t/yr of scope 1 CO2-equivelant emissions (CO2e), the state's Environmental Protection Authority (EPA) said on 29 July. They may also encompass mines not currently included in Australia's safeguard mechanism — which has a 100,000 t/yr CO2e scope 1 emissions threshold.

NSW coal producers participating in the safeguard mechanism generated 12.9mn t of covered CO2e emissions in the 2023-24 financial year ending 30 June. They surrendered 1.4mn Australian Carbon Credit Units (ACCUs) and 600,000 safeguard mechanism credits (SMCs) for the financial year.

Public consultation on the proposals will close on 7 October. NSW's EPA will adapt and formalise the rules after that.

The EPA's consultation opens less than a week after that state's Court of Appeal ruled that NSW's Independent Planning Commission needs to consider the local impacts of climate change when assessing projects with high scope 3 carbon emissions.

Methane Abatement

The EPA wants underground mines with more than 25,000t/yr of scope 1 emissions to start draining methane through flaring or recycling by July 2027. The rules will exclude mines in care and maintenance and those in the state's western coalfields, which have lower methane contents.

The agency may also require high emitting mines — those with scope 1 emissions exceeding 100,000 t/yr — to seal methane leaks in older mining areas by July 2027 and abate ventilation methane by July 2030.

But the sealing and ventilation rules will only apply to mines planning to operate beyond July 2032.

Methane released from underground coal mines produce 8mn t/yr of CO2e emissions in NSW, accounting for 57pc of the state's annual coal sector emissions, based on a 2022 estimate from the Australian government.

Diesel

NSW's EPA also wants to create a pathway to decarbonise mine equipment.

Five percent of fuel used at mines emitting more than 25,000 t/yr CO2e scope 1 emissions will need to be low-carbon alternatives to diesel by July 2030, with the non-diesel requirement rising to 25pc by July 2050. The agency also plans to require 75pc of large mining machines and vehicles to be non-emitting by July 2040, and all of them to be non-emitting by 2050.

The proposed diesel rules will apply to all NSW coal mines — while the proposed methane rules were applicable only for underground mines. Vehicles and machinery will need to be electrified or powered by low-carbon fuels like biodiesel, renewable diesel, or captured methane, under the proposal.

Diesel burning at coal mines produce 4mn t/yr of CO2e emissions in NSW, accounting for 29pc of the state's annual coal sector emissions, based on a 2022 paper cited by the agency.

By Avinash Govind