Evaluating the economics
It covers the production costs, revenue and the benefits of mallee biomass production systems. Detailed economic modelling of the mallee biomass production system and supply chain is included.
A whole-farm economic analysis by NCCARF and the Future Farm Industries CRC in 2013 found that growing mallees as a biomass tree crop was profitable and easy to integrate into farming systems in southern Australian. The report EverFarm® – Climate adapted perennial-based farming systems for dryland agriculture in southern Australia includes results of the whole-farm studies conducted in:
- Wagga Wagga, southern New South Wales
- Hamilton, western Victoria
- Cunderdin, southern Western Australia
- Katanning, southern Western Australia
- wood pellets
Harvesting and transport systems and costs are described in Chapter 4.
Mallee eucalypt crops in Victoria have excellent potential to produce a significant amount of energy for the state. This was the finding of the Victorian government when they looked at the value chain of bioenergy from agriculture.
Mallee–crop competition is a significant cost to farmers and must be considered when designing mallee agroforestry systems. This was the finding of CSIRO in a research paper on the productivity and economics of agricultural crops and pastures growing in the competition zone adjacent to mallee crops. The research was done at 15 sites across the Western Australian wheatbelt.
Biofuel produced from mallee biomass has emerged as a potential future fuel source for the aviation industry. Growing mallee biomass for biofuels [PDF, 738 kB] is an initiative of the Future Farm Industries CRC aimed at stimulating new and sustainable industries across regional Australia.
Almost 80% of the energy inputs required to produce mallee biomass occurs in the harvest and transport stages, mainly from the use of fossil fuels.
An energy balance analysis by the Curtin University Centre for Advanced Energy Science and Engineering, Production of mallee biomass in Western Australia: Energy balance analysis, says mallee production strategies should focus on developing and optimising harvest and transport strategies and logistics, as well as improving the fuel efficiency of machinery used for producing mallee biomass.
Benefits of producing mallee biomass
They can also be integrated into wheat belts to:
- reduce soil salinity
- give shade and shelter for animals
- reduce erosion by acting as windbreaks
- store carbon.
Oil mallees benefit on-farm biodiversity [PDF, 652 kB], especially when planted near areas of native bush. This was the finding from a 3-year study by CSIRO and the Future Farm Industries CRC.
Supplying mallee biomass
The findings are relevant to farmers in Western Australia and mallee areas in New South Wales, Victoria, South Australia and Queensland.
The report also looks at:
- crop production and systems for mallee
- harvesting systems
- transport and storage systems
- processing mallee
- product options from mallee.
Supply chain options for mallee biomass [PDF, 665 kB] are modelled in Chapter 7 of Developing Options for integrated food-energy systems: Supply chain logistics and economic considerations for short-rotation woody crops in southern Australia.
In pellet form, mallee biomass can be used along with coal for combustion in coal-fired power stations – this is known as co-firing.
Delta Electricity is trialling mallee eucalypts to use as renewable biomass fuel at its Wallerawang power station in New South Wales. 200,000 mallee trees are being planted on 20 farms in the Forbes region. Mallee is one of four viable biomass sources in New South Wales [PDF, 55 kb] that Delta has identified.
Growing mallee eucalypts
Mallee eucalypts grow in the semi-arid areas of southern Australia in:
- New South Wales
- north-western Victoria
- southern South Australia
- southern Western Australia.
- Eucalyptus Dumosa (white mallee)
- Eucalyptus socialis (red mallee)
- Eucalyptus gracilis (yorrell)
- Eucalyptus oleosa (red mallee)
- Eucalyptus incrassata (ridge-fruited mallee)
- Eucalyptus diversifolia (soap mallee).
Biomass yield of 10–20 green tonnes per hectare per year can be achieved when mallees are grown in widely spaced two-row belts in alley systems in regions with adequate rainfall and suitable soil types (Section 9.3 of Bioenergy in Australia: Status and opportunities, published by Bioenergy Australia in 2012).
Australia has significant areas of marginal land that may be suitable for planting trees for biomass production, but not for intensive agricultural cropping. Using marginal sites to grow mallee [PDF, 2.4 MB] and tall eucalypts for bioenergy was the subject of a paper presented at the 2012 Australian Forest Growers Conference.
Oil Mallee Australia has published a code of practice and guidance notes for establishing a mallee planting.
Harvesting and transporting
The mallee harvester is the world’s first vertically fed, continuous wood chipper harvester. The design maximises the operational and fuel efficiency of the wood chipper and integrates it with a vehicle.
The harvester simultaneously chops trees and converts them to woodchips in a single pass with no need for separate chipping and transport steps. It is designed to integrate with in-field haulout vehicles and roadside collection and transport, similar to the current supply chain model for sugarcane harvesting.
In 2014, ARENA announced it would fund a project to increase the size of the harvester and upgrade the design to enable it to operate under full-scale commercial conditions.
The $3.5 million project ($2 million from ARENA) is being run by Biosystems Engineering. They aim to collect 15,000 tonnes of chipped mallee at a plantation near Casino in NSW during a 33-day harvester trial. The chips will be used to supplement feedstock to the 30 MW bioenergy power plant at the Broadwater sugar mill in NSW.
The project is scheduled for completion in 2017.
Harvesting and collecting mallee biomass from the field is described in detail in Section 6.3 (‘Short cycle tree crops’) of Bioenergy in Australia: Status and opportunities, published by Bioenergy Australia in 2012, which covers:
- selecting a harvesting system
- machinery options
- relocating the biomass from the plantation (extraction)
- transporting the biomass
- processing the raw material into a form that can be used efficiently as fuel (e.g. chipping and chunking)
- drying the biomass.
147 David Hill Road, Monbulk, Victoria 3793
444 Albany Hwy, , Albany WA 6330
Phone: 0428 939 419
Kent St, Bentley WA 6102,
Phone: 08 9266 9679
175 Liverpool Street, Sydney NSW 2000
Phone: 0419 696 891
Mallee grower and Oil Mallee Association Regional Manager , 26 Jersey St, NARROGIN WA 6312
Phone: 08 9881 5373
Tamworth Agricultural Institute / NSW DPI
4 Marsden Park Road, Calala, NSW 2340,
Phone: 02 6763 1238
168 St Georges Terrace, PERTH WA 6000,
Phone: 0408 907 762
Dept. of Chemical Engineering, Curtin University, Perth, WA
Phone: 08 9266 7592