The final stop before landfill: waste-to-energy plants

A massive waste-to-energy plant south of Perth will be up and running by the end of next year, transforming residential waste including plastics and metal into energy or reusable materials. Construction began on the privately-owned East Rockingham Waste-to-Energy plant in 2020 and by the time it’s fully operational it will deal with 300,000 tonnes of “red bin” waste each year, waste that would otherwise be destined for landfill sites now fast reaching capacity.

“Obviously, the goal is to reduce, reuse and recycle as much as possible,” says Jason Pugh, CEO of the Rockingham facility. “But the residual waste stream, at least for the near term, is here to stay.” A federal government grant of $18 million helped fund the $510 million project.

The plant is one of two waste-to-energy facilities under construction in Australia, both near Perth, and one of hundreds of waste-to-energy and bioenergy projects underway across the nation. Sewage sludge, abattoir waste, household waste, agricultural waste, forestry waste: all can be converted into energy or usable products by using a range of different methods, from anaerobic digestion to pyrolysis, or high-heat decomposition.

Despite the current activity, Australia has been slow to the bioenergy and waste-to-energy field, says Shahana McKenzie, chief executive officer of industry association Bioenergy Australia. “Australia has lagged behind other nations in terms of climate change policy and having a strategic approach to emissions reduction,” she says, adding that years spent debating the basics of climate change stifled the sector’s growth.

At the East Rockingham plant, everything that’s combustible will be burned at high temperatures to produce energy and keep emissions as low as possible. Pugh says the plant has a 60m high stack and “it’s very clean in terms of emissions”.

Just under 29 megawatts of electricity will be generated by the plant every hour and sent straight into the grid, he says. Non-combustible materials, such as metals, glass, sand and rock, will fall through a grate to a separate area for potential crushing and recovery. Magnets will be used to sort metals into ferrous and non-ferrous types and the plant will produce two sizes of aggregate. All will be sold.

Pugh says there are many advantages of a waste-to-energy system compared with landfill. “All the modern cities in the world have waste to energy, they’ve moved away from landfill,” he adds. “Our technology provider, Zurich-based HZI, they’ve done 500 plants internationally.”

The federal government’s Australian Renewable Energy Agency (ARENA) in 2021 released a Bioenergy Roadmap with an overview of the bioenergy sector’s potential: $10 billion in extra GDP per annum and 26,200 new jobs, as well as a potential 9 per cent reduction in emissions, boosting fuel security and diverting waste from landfill.

“Where possible, waste should not be going to landfill, it should go to a higher value purpose,” McKenzie says, noting that amongst other things, waste can be used to produce energy in the form of biogas. About 240 anaerobic digesters are now at work across Australia capturing gas from organic waste streams. This biogas can be used to provide on-site power at the sewage treatment plants, abattoirs, and landfill sites where it is produced.

Transformed into biomethane, biogas can also be injected directly into the gas network, McKenzie says. Sydney Water’s wastewater plant at Malabar began adding biomethane to the gas network in June this year, and McKenzie says it’s been estimated that biomethane could supply 20 per cent of Australia’s domestic gas use by 2030.

Meanwhile, a CSIRO-Boeing Sustainable Aviation Fuel Roadmap published in August found Australia was in a “prime position” to capitalise on abundant organic waste streams – feedstock – to produce sustainable aviation fuel. The report estimated that by 2025 Australia would have sufficient feedstock resources to produce almost five billion litres of sustainable aviation fuel – nearly 60 per cent of the Australian jet fuel demand projected for 2025.

Across the nation, in the central NSW town of Manildra, MSM Milling is using biowaste to power a boiler used for oil seed milling and processing – principally for producing edible canola oil and other canola oil products. Before investing in the biomass boiler, LP bottled gas was trucked into the plant to generate the steam needed for the production, says MSM Milling director Bob Mac Smith.

“We need a lot of steam,” he says. “It got crazy expensive; not only were we paying for the product we were paying for the transport as well.” He and his colleagues considered alternatives and finally chose to use a $2 million federal government grant to assist with the purchase of an automated biomass boiler made in Denmark, where biomass has long been used to produce thermal energy.

Operating since 2019, and costing $5.8 million, the boiler now consumes about 100 tonnes of biomass each week, waste such as thinnings and sawdust residue from local state forestry managed operations, and it has generated a lot of interest from other Australian operations, Mac Smith says.

“Several units have been installed by other regionally-based businesses since this one was put in,” he adds. “This one has been terrific.”

Australian Financial Review