The Potential Supply of Biomass for Energy from Hardwood Plantations in the Sunshine Coast Council Region of South-East Queensland, Australia

Small community-based biomass energy systems sourcing feedstocks from local small-scale forests are common in the northern hemisphere but are few in Australia. Fine-grained analyses of feedstock availability are an important precursor to increased investment in these systems in Australia. This study presents estimates of the potential biomass for energy supply from hardwood plantations within the Sunshine Coast Council region of southeast Queensland. The region’s 1,120 ha of private farm forestry, corporate-owned and joint venture hardwood plantations are predominantly small-scale (<20 ha) Gympie Messmate (Eucalyptus cloeziana) monocultures. Plantation age-class and corresponding area, productivity and management history findings and informed harvest-related assumptions underpin a 20-year forecast of biomass yields from a suggested plantation harvest schedule. The biomass yields are underbark stem-wood quantities assumed to be unmerchantable for higher-value solid-wood products. Future thinning (at age 12 years) and clearfell harvests (age 25 years) could provide minimum woody biomass yields of 30 and 108 GMt/ha respectively. Closer to 200 GMt/ha may be available from clearfell harvests of poorly-managed farm forestry plantations. The forecast annually available biomass supply is highly variable and mostly of small quantities. Biomass energy plants seeking a sustainable supply of feedstock must therefore access additional locally-available waste biomass. Further research is required to identify and quantify these sources. Field trials are also required to understand better the likely product mixes and available volumes of biomass for energy from the region’s various hardwood plantations and to test for efficient integrated biomass harvest and supply chain systems for the sizes and terrains that are characteristic of these plantations.