Researchers at the University of Newcastle have developed a methane pyrolysis process specifically designed for coal mine methane, producing hydrogen gas and solid carbon without generating CO2 emissions.

The technology addresses a significant but often overlooked emissions source. Coal mines release about 70 million tonnes of methane annually in Australia, accounting for roughly 14% of national greenhouse gas emissions. Most of that methane is currently vented to the atmosphere because concentrations are too low for conventional use.

Professor Alison Worrall, who leads the research, said converting methane to valuable products makes emissions reduction economically attractive. “Rather than just capturing methane and flaring it to CO2, we’re splitting it into hydrogen and carbon. Both are valuable products, and you’re not creating any CO2 in the process.”

Methane pyrolysis involves heating methane to high temperatures in the absence of oxygen, causing it to decompose into hydrogen gas and solid carbon. The process requires energy input but less than conventional hydrogen production methods that generate CO2 as a byproduct.

The solid carbon produced is primarily graphitic carbon with potential uses in construction materials, soil amendment, or energy storage applications. Quality varies depending on reaction conditions, and producing high-value carbon products requires careful process control.

The Newcastle system uses molten metal catalysts to facilitate methane decomposition at lower temperatures than conventional pyrolysis. This improves energy efficiency and reduces equipment costs compared to high-temperature systems.

One challenge is that coal mine methane contains varying concentrations of methane mixed with air, ranging from 20% to 60% methane depending on mining activities and ventilation. The pyrolysis system needs to handle these variations without performance degradation.

The research team developed a pre-concentration system that uses pressure swing adsorption to increase methane concentration before pyrolysis. This improves process efficiency and hydrogen yield.

The system operates continuously, processing coal mine methane as it’s extracted from active or closed mines. Many closed Australian coal mines continue releasing methane for decades after mining ceases, representing long-term emissions sources that need management.

A pilot plant is operating at a coal mine near Singleton, processing about 100 cubic metres of methane daily. The hydrogen produced is used onsite for mine equipment and electricity generation, while carbon is being tested in concrete formulations.

Initial results show the system can achieve 70-75% conversion of methane to hydrogen, with the remainder used to fuel the pyrolysis process. That’s slightly lower than theoretical maximum but acceptable for commercial viability.

Economics depend heavily on the value realised from hydrogen and carbon products. If hydrogen can be sold at $4-5 per kilogram and carbon at $100-200 per tonne, the process could be economically attractive even without carbon credit revenue.

Adding Australian Carbon Credit Units from emissions reduction strengthens the case further. Coal mine methane abatement projects can generate credits worth $25-35 per tonne of CO2-equivalent emissions avoided.

Several coal mining companies have expressed interest in the technology because it addresses both environmental and economic objectives. Mines face increasing regulatory pressure to reduce methane emissions, and producing revenue from those emissions makes compliance less costly.

The research received $4.5 million in funding from the Australian Renewable Energy Agency and coal industry partners. ARENA sees coal mine methane conversion as a near-term opportunity for clean hydrogen production using existing infrastructure.

Australia has extensive coal reserves and will continue coal mining for decades even as domestic coal use declines. Managing methane emissions from ongoing and closed mines is necessary regardless of coal’s long-term future.

The Newcastle technology could also apply to landfill gas, biogas, and other low-quality methane sources that are difficult to use with conventional technologies. Expanding applications beyond coal mines would increase market size and improve commercial prospects.

Some environmental groups criticise methane conversion technologies as extending the coal industry’s social license rather than accelerating transition away from fossil fuels. They argue resources should focus on renewable energy rather than making coal mining less emissions-intensive.

The counter-argument is that reducing emissions is valuable regardless of source, and coal mine methane will be released whether or not mining continues. Converting those emissions to useful products provides environmental and economic benefits.

The technology isn’t unique to Newcastle. Several international companies are developing methane pyrolysis for various applications. Competition focuses on achieving low production costs, high product quality, and reliable operation with variable feedstocks.

Australian coal mine methane represents about 20 petajoules annually of energy that’s currently wasted. Converting even 25% of that to hydrogen would produce roughly 200,000 tonnes of clean hydrogen annually, enough to supply several industrial facilities or support hydrogen vehicle fleets.

Whether the technology achieves significant deployment depends partly on hydrogen demand development. Australia’s hydrogen strategy targets export markets, but domestic demand is also growing as industries explore decarbonisation pathways.

The pilot plant will operate through 2026, with commercial deployment decisions expected in 2027. Several coal companies are considering retrofitting existing methane drainage systems with pyrolysis units as emissions regulations tighten.

The Newcastle research demonstrates how waste streams can become feedstocks for valuable products with appropriate technology. Whether this particular approach succeeds commercially remains to be seen, but it represents the kind of innovation needed to address industrial emissions sources that lack obvious solutions.