In Morewell, Victoria the streets are wide and clean and the people are friendly as one might expect in rural communities. The local economy is heavily invested in coal mining to support the State’s baseload power. Victoria holds 25% of the world’s known lignite reserves. Victorian lignite is a relatively immature form of lignite, containing a naturally high proportion of humic substances from plant material, making it very similar to the organic matter in soil. 65Bn tonnes (80%) of Victorian lignite reserves are located in the LaTrobe Valley. As the State transitions to renewable power generation anticipating the end of mining coal for power generation, La Trobe Valley communities are looking to establish alternative industries to maintain employment, livelihoods and the historical fabric of their communities.
Rather than being a dirty product that should not be mined, scientists understand that Victorian lignite has unique physical and chemical properties best suited for use in innovative high value-added emissions-reducing industries like green hydrogen production, activated carbon and as an organic fertiliser substrate. These properties include low density and high porosity, a high surface area and liquid absorptive capacity, a lower concentration of impurities (ash, sulphur, heavy metals, and nitrogen) and a high composition of organic matter when dried in the form of exchangeable cations (positively charged metals except for hydrogen) which enhances their binding quality to liquid additives. Victorian lignite is also cost effective to mine compared to the manufacture of biochar
However, Victorian lignite has a high moisture content (55-65%). The inability to dry lignite economically at scale to a moisture content of 25-30% (or lower) depending on the application has been the main barrier to unlocking its use in these value-added applications. Ahrko Holdings Pty Limited has developed a patented evaporative drying system to dry lignite and lignite fines economically and at scale to unlock these applications.
The innovative potential of lignite is best illustrated in relation to its use as a fertiliser substrate.
Published research in Australia, Poland, and South America where there are substantial lignite deposits have demonstrated 4 benefits of lignite-based fertilisers –
1. As a soil amendment (improves water-holding capacity, nutrient retention (NUE and phosphorus), reduce soil acidity/alkalinity (improve pH), and ameliorates sodic soils)
2. As an organic fertiliser substrate. Fertiliser manufacturers already produces blended organic and chemical fertiliser products which include powdered brown coal as a source of humates. Tony Patti at Monash University has developed processes to optimise the performance of N- and P-containing organic/lignite blends.
3. As a carrier for microbial bio-fertilisers. Biofertilisers are sold as live formulations of microorganism for application to the soil or to plant seeds or roots. Peat and lignite are preferred carriers. Studies at Monash University on rice showed that lignite inoculated with nitrogen fixing bacteria had a substantial impact on plant growth compared to a peat control group.
4. As an effective way to reduce fertiliser emissions. Use of lignite-based fertilisers has ben shown to reduce evaporative emissions and nutrient leaching into waterways.
These benefits come with the potential to reduce nitrogen use without sacrificing plant biomass or yield – a sort of ‘holy grail’. Synthetic fertilsers offer none of the above benefits.
Ahrko Systems is currently working with partners to establish field trials to commercialise at scale the use of low-cost lignite-based fertilisers to (in part) replace synthetic fertilisers that provide none of these benefits. Ahrko is located in Gippsland and is a good example of an innovative enterprise using science to transform our perception of brown coal (lignite) as a dirty product into a sustainable green product with the potential to feed the nation in a more sustainable way.
Triple Innovation is partnering with Ahrko Systems to develop the business model and research ecosystem, to commercialise its fertilser products and develop offshore markets for its core dried lignite product, and to engage funding support along the way.