By Dr Robin Branson PhD, MBA, BSc. (Hons), Director Australian Industrial Ecology Network (retired)

The article in Q1 of The ASIA Miner flagged a short detour to the AIEN Forum on Energy from Waste (EfW), which took place in Ballarat, Victoria from 19-22 February 2018.

It was the third in a continuing series of annual events, which began in 2016. That Forum presented an overview of EfW in Australia whereas the focus in 2017 was on understanding the various technologies commercially available and those being developed. Following the progression set by the first two Fora, the event in February 2018 concentrated on the thrills and tribulations of developing projects in practice. The program included guest speakers from the UK, continental Europe, the USA and Canada, whose knowledge and experience was debated in relation to developments in Australia.

Every major process for extracting energy from waste was canvased. They included large scale thermal treatment of municipal solid waste (MSW); local combined heat and power plants (CHP); plasma gasification, pyrolysis and hydrogen energy systems. Importantly, biological processes also featured in the program, mainly anaerobic digestion (AD) to generate fuel gas from domestic and industrial putrescible waste.

Commercial topics included managing project inception and development; characterisation and preparation of fuel for specific processes; assessment of markets for ‘off-take’ products such as electricity or liquid fuel; analysis of risk; the legal ‘minefield’ confronting proponents applying for government approvals and, of course, establishing the ‘business case’ and obtaining funding, which are critically important in any project.

An entire session comprised discussions between the audience and a panel of representatives from various State Environmental Protection Agencies. The objective was to canvas issues confronted by both private and public sectors during the process of approving projects. Such opportunities are rare in Australia, yet mutual understanding greatly facilitates innovation and the development of appropriate infrastructure. Selecting the right technology and infrastructure for the intended purpose was a recurring theme. Speakers emphasised the wisdom of truly understanding what is appropriate for a given situation and carefully planning its implementation.

Resource recovery a common theme

Regarding purpose, the overarching theme of resource recovery emerged during the Forum. This was an encouraging, if somewhat surprising development because ‘collective’ thinking in Australia about this topic had not been prominent in previous Fora. A core concept of industrial ecology in relation to resource recovery is the notion of a waste hierarchy, myriad examples of which float around the internet. In previous Fora, this notion was barely mentioned. In 2018, almost all speakers referred to the hierarchy in one way or another. The inference is that recovering resources wherever possible is gaining increasing attention from people in a position to make a real difference in practice. The aspiration is that future generations will transform such thinking into ‘collective’ action. After all, it is only thorough action that sustainable development is possible.

MSW and that old chestnut ‘residual’ waste

While thinking on one front may be shifting, some major controversies seem to endure unchanged. For example, the mantra justifying thermal treatment of Municipal Solid Waste (MSW) is that it will only burn residual waste that would otherwise have gone to landfill. The problem is: no categorical definition exists of what ‘residual’ actually means. Although long-term supply contracts of MSW for thermal processing might include some flexibility to adjust fuel specifications, the underlying business model depends on there being a minimum amount of high-energy material available, which generally requires a significant proportion of hydrocarbons, such as plastics. ‘Residual’ usually means everything left after (conveniently) extracting materials that can currently be recycled. That could include significant amounts of plastics that might not be recyclable now but could be in future, as technologies improve. Such supply arrangements potentially stifle innovation and tend to minimise rather than maximise the highest net recoverable value (HNRV) of the materials concerned. The whole point of recovering resources from waste, be it domestic, industrial, agricultural of from extractive industries, is to achieve the HNRV possible at any given time.

Conserve or burn?

A corollary to the ‘conserve or burn’ debate is what to do with recovered materials. Logically, they must either be returned to the ‘productive’ economy or, theoretically at least, they should be stored, that is, conserved for future use. In commercial terms, there must be a market demand for recovered materials, or significant and continuing government (societal) support, to make recovery a commercially viable or otherwise a socially beneficial proposition. The dearth in Australia of demand for recovered materials, especially plastics and timber, is particularly acute and becoming more so, as imports of finished goods manufactured overseas supplant local production. Huge strategic problem – for Australia!

Meanwhile, some of the stuff that will burn is burnt but as a specially prepared fuel, generally referred to, interchangeably, as processed engineered fuel (PEF), refuse derived fuel (RDF) or solid recovered fuel (SRF). These are high quality fuels, produced to specifications for particular purposes, which are exported as well as used domestically and represent the HNRV for their constituent materials, given prevailing technologies and market conditions.

Australia’s licencing lag

A stubbornly recurring issue and one of considerable sensitivity on both sides of the dilemma is the difficulty and cost of obtaining licenses to operate in Australia. In a case study from Germany, the proponent of a medium-scale EfW project constructed the plant and begin operations within eighteen months of first applying for government approvals and social license. The case study of a similar project in Australia, illustrated a similar application process, which took over three years – just to obtain government approvals.

Is energy from waste needed?

Swirling around the entire Forum was the simple, though provocative question of whether or not Australia actually needs energy from waste. Analysis presented by the CSIRO concluded that if all the unprocessed MSW arising in Australia, including all the plastics and other high-calorific material were converted into energy of various forms, it would provide about 1% of the country’s annual demand. Aside from the argument that we should achieve the HNRV, it would seem that EfW in Australia is predominantly a waste management strategy.

EfW and mining

Implications for industrialised societies in general may be obvious but one might well wonder what EfW and recovering resources has to do with mining in particular. Seemingly, perhaps, not much on the surface of things but there are some undercurrents, which may be worth keeping an eye on. The more resources are conserved, the less will be mined. More immediately, though, at least three possible opportunities may attract some interest from miners.

The most obvious is developing infrastructure to use putrescible and high-calorific waste arising on mine sites to produce energy for the site and local communities. Perhaps not so obvious is urban mining: digging up landfill sites to recover materials that have a potentially positive HNRV in the future.

Another angle is using worked-out mines as repositories for materials recovered now but cannot be used immediately, even though it is known that they could be used in future. Plastics, tyres and conveyor belts would be candidates for this strategy. Given there is insufficient demand currently in Australia for all such recoverable materials, they could be densified, for example, as ‘hydrocarbon ingots or briquettes’ and stored safely in mines so their value can be retrieved in future.

Maybe a fanciful notion at the moment, but one never knows how things will change or when. IE in mining? The next article will be right back on topic!

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