Can Australia Support Straw-fired Power?
An abstract of a presentation to the Australian Bioenergy Conference 2013
To consider straw as a feedstock and how straw is produced and accumulated by commercial power plants internationally can provide some valuable insights into the feasibility of similar plants operating in Australia.
Information has been gathered from visits to commercial scale straw power plants in the UK (Cambridge and Yorkshire) and Spain (La Rioja region).
Bale in-feed system for the pellet plant for Drax Power Station Yorkshire UK
The high and medium rainfall zones of Australia’s grain growing areas offer great scope for straw production. There are notable differences in straw production to those of than the smaller scale paddocks in the UK and Spain. Straw yields are smaller to those in the UK yet comparable yields in Spain.
While moist crop stubbles in the UK and Spain allow straw baling several days after harvest, conditions are not conducive to the baling of straw during the harvest operation. The warm, dry spring weather in Australia allows capturing dryer straw and the ability to adopt technologies such as the Glenvar Bale Direct system, which can save harvest, costs and capture weed seeds at harvest.
Once harvested, the transport of straw can be more difficult and costly depending on the load dimensions permitted by regulators. Changes to transport rules in Australia have overcome many of these problems and new high-density balers are further improving transport efficiencies.
Compared to international markets, straw has relatively lower demand in Australia. Straw is purchased from a large number of producers. Compared to the current industry structure in Australia, supply chains adopted in Spain and the UK are more extensive as they require over 150,000 tonne per year per plant.
Operating costs for a 30 MWe straw-fired power plant Ref: Stucley et al 2012, Bioenergy in Australia
Finally the affordability of straw relative to the energy markets of each country are compared to rate the feasibility of straw to energy plants. Government policies and power generation are impacting on the viability of biomass to power projects in Australia when modelling the affordability of biomass for energy.
The current carbon price and Large-scale Generation Certificates (LGC) means that an affordable price for biomass (with a Higher Heating Value of at least 12 MJ/kg) is $69.60/tonne. This is not commercially competitive in the market.