BY JOHN WALKOM CHAIR. REGIONAL DEVELOPMENT AUSTRALIA ORANA NSW

As the global economy attempts to address clim:ate change by reducing its reliance on fossil fuels, there is an urgent need to find alternatives for a wide range of applications currently supplied by these sources.

Energy is perhaps the most obvious of these; the processes for generating energy from wind and solar radiation are well established and their use is expanding rapidly.

But what about non-energy products derived from coal? Where can these carbon products come from, if not from coal? The only other source of carbon available is biomass - usually defined as material that is living or less than about 100 years-old. And how is it converted into useful products?

That's what a BioHub is for. It is simply a facility that converts this material into other products. Depending on the nature of the biomass fed into it, these products include industrial reductants used in metal smelting, biochar for specialty fertilisers, essential oils and energy.

The processes that a BioHub employs also vary according to the inputs available, but typically involves either anaerobic digestion/fermentation when wet wastes are used, or torrefaction/ pyrolysis when dry wastes are used. Torrefaction/ pyrolysis is the process applicable to the Orana BioHubs.

Torrefaction is essentially a drying process which involves heating the biomass at temperatures typically between 200 and 300 degrees Celsius to drive off water and volatile substances. Pyrolysis is heating at higher temperatures without oxygen, typically 480 degrees but up to 980 degrees for short periods. The absence of oxygen is important - adding oxygen would result in burning, producing ash rather than biochar. Torrefaction and pyrolysis are both used extensively in other industries.

RDA Orana, together with funding partners, commissioned a feasibility study into the establishment of one or more BioHubs in the Orana region. The aim was to determine whether there is sufficient biomass available in the region to justify investment in a facility that converts this material into carbon-based products that can be substitutes for coal in existing markets. Of course, biomass can also be used to produce "clean" energy, but this was not the focus of the Orana BioHub Project.

The study was undertaken by EcoWaste Pty Ltd. It concentrated on biomass that is a waste, residue or byproduct of an existing enterprise. Examples include crop stubbles, spoiled grain, sawdust and sawlog offcuts, sludge from dairies and piggeries, animal manures and native vegetation cleared in accordance with approvals. Although some of these products already have markets, in general they are undervalued and the main objective is to dispose of them as cheaply as possible.

The BioHub concept turns this "least cost disposal" philosophy into one of "highest net value" - putting every biomass input to its most productive and highest value use given its innate qualities. An abattoir provides a useful analogy - it is not logical to make blood and bone fertiliser out of fillet steaks, but it's a valuable end for all the materials that have no better use. In between, there's a whole range of different cuts that can be put to multiple uses depending on the market.

And so it is with biomass. Based on the biomass available in the Orana region, the study considers two main BioHubs - one based at Cobar and one at/ near Dubbo, with smaller facilities throughout the region undertaking pre-processing as necessary.

The Cobar BioHub will rely on legally-cleared jnvasive native scrub as its biomass input. Because cleared vegetation contains a variety of species, there is a range of uses to which it can be put to achieve its highest net value.

The study applied the "abattoir" approach, first separating out the "fillet steaks" - the high-value timbers that are best as sawlogs or for specialty uses such as cabinetry and musical instrument manufacture. From the remaining vegetation, certain hardwood species would be used to produce industrial carbon-based reductants used for metal smelting and manufacture, replacing coke (from coal) in this process. After this "boxed meats" material has been removed, the remaining vegetation could undergo processing to extract essential oils before being converted into biochar - the abattoir equivalent of "blood and bone". Energy produced from the process will power the facility, with surplus energy available for sale.

The Dubbo BioHub would be fed by a wide range of biomass " inputs, some of which are consistently available but most are seasonal or sporadic - after all, no-one sets out to .make waste, it is only generated from the primary enterprise: It is difficult to justify significant financial investment on the basis of "as available" supply, so it is important to identify a "mainstay" input for which supply could be contracted.

For the Dubbo BioHub, this will be forestry residues and byproducts from activities in the north of the region. The organic fraction of Council wastes is another possibility, but is subject to strict regulation because of the potential presence of toxic substances. Other inputs would be utilised as available.

Biochar is the main output proposed from the Dubbo BioHub facility. It has a range of uses, but the vision for this facility is to use it in the manufacture of "prescription" fertilisers.

In addition to carbon, biochars contain trace elements that make them valuable for correcting deficiencies in the soil. Which trace elements are present, and in what concentrations, depends on the nature of the biomass input - so biochars created from different inputs will have different chemical properties. This is great from the perspective of fertiliser manufacture, because it allows blending of different biochars to create a product perfectly suited to a particular soil and crop combination.

Being able to apply only those nutrients that are actually required will be a significant cost The study applied Ute "abattoir" approach, first separating out Ute "fillet steaks" -Ute high-value timbers that are best as sawlogs or for specialty uses such as cabinetry and musical instrument manufacture. saving to growers, and will help prevent problems associated with over-application of nutrients. Adding more carbon to the soil is another significant benefit.

Sounds a bit far-fetched? Not so - research using soils from the Wellington district and biochar based fertilisers showed equivalent or better results than traditional fertilisers in pot trials undertaken by the University of NSW. Paddock trials are next, and are expected to show similar results.

Facilities such as these. don't come cheap - the proposed BioHubs for Cobar and Dubbo would cost about $38m each to construct. However, based on the information gathered by EcoWaste during the study, this could be recouped in as little as 3 to 5 years. These facilities can be built in stages - starting off small limits the initial capital outlay, with expansion taking place as markets develop. The benefits to the region would be significant. Those enterprises that contribute biomass would receive additional income and/or reduced waste disposal costs, improving the viability of the main enterprise. At full scale, these BioHubs would generate 30 to 40 skilled jobs directly, and provide many other commercial opportunities in support.

It is likely that the BioHubs will be eligible to generate energy certificates for sale under the Government's Renewable Energy Target, and will contribute to reducing greenhouse gases while maintaining or improving productivity. Private investment is being sought to construct and operate these facilities. There has been .interest from both Australian and international investors, and negotiations are continuing. Watch this space …


p4. Friday 19.08.2016 to Sunday 21.08.2016 I Dubbo Weekender

Tags: biohubs, cobar, orana