The emerging Waste-to-X opportunity in Australia

Meanwhile, other regions across the world are exploring novel ways to decarbonise the waste industry; seeking alternative ways to avoid landfill and utilise waste and biomass resources, which would otherwise contribute to greenhouse gas emissions.

This is where the emerging opportunity of Waste-to-X, including thermochemical and anaerobic digestion processes, comes in. Broadly speaking, the underlying waste conversion technologies can be classified as either:

• thermal conversion technologies, such as gasification, pyrolysis and hydrothermal liquefaction (HTL), or
• biological conversion technologies, such as anaerobic digestion.

Of these, anaerobic digestion and thermal gasification offer the greatest potential for deployment at the scale necessary to assist so called hard-to-abate industries on their decarbonisation journey.

Projects using those process technologies seek to produce alternative fuels such as Sustainable Aviation Fuel (SAF), green methanol (from carbon capture or from thermal gasification in combination with green hydrogen) and biomethane (from the upgrading of biogas from anaerobic digestion or thermal gasification in combination with green hydrogen).

Driving forces from industry include the International Maritime Organisation, which has set a target of net zero by 2050 with an ambition to increase the uptake of zero or near-zero greenhouse gas emission technologies, fuels and/or energy sources such that this represents at least 5% (striving for 10%) of the energy used by international shipping by 2030. The aviation industry, which has a focus on alternative fuels such as SAF and hydrogen, also has a significant interest in these Waste-to-X projects.

In the circular economy, waste is a resource. One way to use this resource smartly is as a source of secure, stable and climate-friendly energy. In this way, Waste-to-X could play an important part of the waste hierarchy by making use of mixed waste that cannot be avoided or recycled, reducing the need for fossil fuels in hard-to-abate sectors and landfill disposal.

Anthony Douglas, Senior Consultant at Ramboll, will discuss this emerging opportunity for the alternative fuels sector at the Waste Management and Resource Recovery Association of Australia 2023 Energy from Waste Conference in Sydney when he presents on Emerging trends and innovations in Waste-to-X on Thursday 2 November.

Emerging trends and innovations in Waste-to-X

In Australia, there is a growing interest in generating alternative fuels from waste. “X” could include hydrogen, biomethane or other alternative fuels and feedstocks for downstream chemical production.

There is a range of different interactions between various conversion technology groups that could result in a hydrogen outcome, a liquid fuel, or a product like methanol, which is a feedstock for a whole range of other products and chemicals for example. Many new opportunities could arise as more of these conversion technologies mature and become commercial.

Waste-to-X is still an emerging area globally, with no commercial Waste-to-X facilities converting mixed waste with thermal conversion technologies operating yet. Notably, there are several niche thermal (pyrolysis) facilities converting separated waste fractions (such as source separated plastics and tyres) into various products, at commercial scale.

However, some industries in Australia, such as aviation, have been vocal about using this technology to develop a decarbonisation pathway. Several local councils are also looking to see if they can divert their residual waste to an “X” outcome, as an alternative to landfill or even waste-to-energy.

Overcoming the barriers to Waste-to-X

While there are opportunities to develop Waste-to-X in Australia, there are several barriers that Ramboll can help clients navigate.

The key issue is that thermal conversion technology for processing mixed waste feedstocks is not yet at the stage where it is commercially viable for Waste-to-X, while biological pathways for source separated organics are viable and have been demonstrated at scale. There are also regulatory barriers, and these can vary from State to State, including a cap in Victoria on how much waste can be processed using thermal conversion technologies.

On top of the technology readiness and policy uncertainty in Australia, the biggest barrier is access to feedstocks, including mixed waste streams controlled by councils, source separated waste streams from industry and agricultural waste streams. Waste-to-X projects need suitable feedstocks in sufficient quantities to service the long-term contracts that will be required to finance these facilities.

Despite these barriers, we need to remember that many large organisations have waste problems that they are trying to solve. They may be paying for their waste to be taken to landfill whereas they could be diverting some of this waste into a renewable and sustainable fuel and/or into energy.

So Australia needs to be ready for Waste-to-X and it is important to start planning for this industry now as the technologies develop.

Cleaner but not necessarily clean

Using mixed waste to develop a cleaner fuel can also create an assortment of challenges. Mixed waste will most likely include some fossil fuel components, so it is not 100% renewable.

This needs to be considered when setting net zero targets. While Waste-to-X will be cleaner; it is not necessarily clean. There is space for low greenhouse gas emission fuels as we move towards net zero, but both companies and consumers need to expect that the production price per unit ‘X’ will generally be higher than the fossil fuel derived equivalent. Carbon capture is also an option, though this adds cost and complexity and requires a means to sequester or utilise the captured carbon dioxide.

When considering Waste-to-X against alternative ways to lower their emissions, some companies may therefore consider paying for offsets as opposed to paying for a more expensive fuel to get the same outcome.

On the other hand, source separated organic waste and agricultural waste (biomass) are 100% renewable. Anaerobic digestion and carbon capture can produce carbon-negative ‘X’ from these feedstocks.

Cost and process complexity

Waste-to-X proponents also need to consider the costs and process complexity associated with the production of ‘X’.

In most tried and proven waste-to-energy processes, the whole waste stream is utilised as fuel. However, with Waste-to-X, a mixed waste feedstock will generally have to be pre-sorted and pre-treated to produce a refuse derived fuel (RDF) before it can go through the conversion system.

With this, comes extra capital and operating costs as well as process variability and potential for lower operational availability, due to the nature of the mixed material. It introduces a whole range of challenges for the downstream process, which are not nearly as significant for waste-to-energy.

Councils should be cautious at this stage

Proponents of thermal conversion technologies are actively pursuing feedstock commitments from councils around Australia, promising a green, clean future for their mixed waste stream.

However, councils will need advice to understand the true status of technology readiness and to critically assess the commercial viability of the alternative waste treatment technology or service offering.

A watching brief on thermal Waste-to-X

Ramboll has been conducting extensive technical and commercial due diligences into many of the potential Waste-to-X technologies. We have a watching brief worldwide on where these technologies are being developed, where they are being implemented and at what scale.

Currently there are two thermal Waste-to-X facilities under commissioning: one in the US and one in Canada. There is another in the UK, which has been reported to be in commissioning for some time. We are watching these carefully for application in Australia.

There is certainly an increasing interest in thermal Waste-to-X, both globally and in Australia, but there are some barriers for this industry to overcome before it becomes commercially viable in the Australian context.

Any business considering investing in this industry must do a thorough due diligence and consider those areas discussed in this article.

Having worked on waste-to-energy projects in 55 countries and provided consulting engineering services for close to 200 new units and retrofits, Ramboll is internationally recognised as the world-leading waste-to-energy engineering consultant.