Despite the momentum towards increased renewable energy in electricity generation, Australia’s coal sector is poised to maintain a significant role in the global power landscape for the foreseeable future.
Thanks largely to advancements in carbon capture and storage (CCS), enhanced processing efficiencies, pollution control technologies, favourable geology, and strong market dynamics, the domestic coal industry is expected to hold its position as the world’s fifth-largest coal producer for several decades.
The country’s two primary onshore energy hubs – Queensland’s Bowen Basin and New South Wales’ Hunter Valley – yield high-quality, energy-dense bituminous coal.
This type of coal is conducive to carbon dioxide storage, generated from the combustion of fossil fuels, and supports the use of high-efficiency, low-emissions (HELE) technologies, which are essential for achieving near-zero greenhouse gas (GHG) emissions from coal.
Bituminous coal also plays a role in coal gasification, a vital thermal-chemical process that employs more efficient technology than traditional pulverised fuel to produce synthetic natural gas (SNG). This fuel can be used for power generation, heating, and chemical production.
According to FutureCoal, CCS can capture up to 90 per cent of CO2 from flue gases released in power plants and industrial facilities. The captured CO2 can then be safely stored underground or repurposed for various applications.
With CCS technology, it is possible to retain the advantages of fossil fuels, such as reliability and robust storage capabilities, while mitigating potential energy insecurity.
The primary methods for CO2 capture include post-combustion, pre-combustion, and oxy-fuel combustion.
In post-combustion, CO2 is separated from flue gas using a chemical solvent after combustion.
Pre-combustion methods convert the fuel into a gas mixture of hydrogen and CO2 before burning, while oxy-fuel technology combusts fuel in nearly pure oxygen, producing carbon dioxide and steam, which can then be collected.
Once captured, CO2 is compressed into a liquid state and transported via pipeline, ship, rail, or road tanker.
The final step involves injecting the CO2 into deep geological formations, typically at depths of over a kilometre, where it can be permanently stored in depleted oil and gas reservoirs, coalbeds, or deep saline aquifers with suitable geology.
Ultimately, carbon sequestration is critical for combating climate change, protecting the environment, and fostering sustainable energy practices.
Meanwhile, HELE plants enhance thermal efficiency from the global average of 37.5 to 49 per cent, creating opportunities to reduce global emissions by two gigatonnes.
They emit 25 to 30 per cent less carbon than the average of existing global power fleets and up to 40 per cent less than the oldest technologies.
Although initial capital costs are higher, HELE technology requires less coal per unit of electricity produced, resulting in significant operational cost savings over the asset’s lifespan. Currently, HELE facilities operate in 23 countries across Europe, Asia, the US, and Australia.
In a HELE coal power system, essential components from conventional coal plants operate at higher steam temperatures and pressures, thus enhancing efficiency.
This system can include high-pressure (HP), intermediate-pressure (IP), and multiple low-pressure turbines, with steam passing sequentially through these turbines.
Additional efficiency gains can be achieved by reheating steam between the HP and IP turbines, either once (single reheat) or twice (double reheat), with the latter providing a more efficient system but requiring higher capital investment.
According to the World Coal Association (WCA), pollution controls in coal-fired energy production can reduce GHG emissions by 90 to 99.9 per cent, while also controlling pollutants such as sulphur and nitrogen oxides, particulates, and trace elements like mercury.
To achieve these reductions, technologies such as electrostatic precipitators, fabric filters, selective catalytic reduction systems, and various scrubbers are employed to purify emissions before they enter the atmosphere.
“This has largely been accomplished, and the current challenge lies in the application of ‘off-the-shelf’ technology,” noted the WCA.
Furthermore, coal gasification presents several advantages over traditional combustion methods. It reduces local air pollution by purifying the produced gas before use and enables the capture and utilisation of CO2 and other GHGs emitted during the process.
“Coal gasification can also generate hydrogen for various applications, including transportation, electricity generation, industrial processes, and heating,” FutureCoal noted.
The gaseous products from gasified coal can also be transformed into ammonia, an essential ingredient for fertilisers used in agriculture.
In terms of Australian coal demand, alongside Chinese and Indian markets, the Association of Southeast Asian Nations (ASEAN) – which includes Brunei, Cambodia, Indonesia, Laos, Malaysia, Myanmar, the Philippines, Singapore, Thailand, and Vietnam – is emerging as a significant customer as it evolves into a key manufacturing hub for international firms seeking to diversify their supply chains.
A report by the WCA and the ASEAN association earlier this year projected that overall energy consumption in ASEAN is expected to surge by 145 per cent by 2040, increasing to 922 million tonnes of oil equivalent from 375 Mtoe in 2017, with coal accounting for up to 47 per cent of this total.
“All fuel sources will be needed to meet ASEAN energy demand,” the report stated.
“An effective and sustainable energy policy must integrate environmental imperatives with legitimate goals of energy security and economic development, including poverty alleviation.
“This necessitates a role for cleaner coal technologies, such as high-efficiency low-emission coal-fired power generation and carbon capture, use, and storage.
“Any response to climate change must recognise diverse starting points, perspectives, and priorities, providing a long-term vision for the future.
“Policy support can address environmental concerns while acknowledging the benefits of a diverse and secure energy mix.”
