What is Biomass?
Biomass is any grown product and it generally refers to burnable natural material such as woodchips, wheat stalks, or bagasse from sugar refining.
What energy can be generated from biomass?
Biomass can be burned in a biomass boiler to generate hot water or steam. In larger applications, steam can also sometimes be used to spin a steam turbine and generate electricity.
Where is biomass available and what is the cost?
Biomass is available from a range of applications, but if it is a natural waste product, such as forest waste, green trimmings or sawdust and it can be burnt, and is available in large quantities, then it is a good fuel for a biomass boiler. If no biomass waste product is freely available, it can generally be purchased from between $50-$100 per tonne from local sawmills or alike. This equates to $3 to $6 per GJ, which is generally much less than the cost of gas fuel.
Are they environmentally friendly?
Biomass boilers use materials that extracted carbon out of the atmosphere in order to grow. Burning these materials in an efficient boiler recombines this carbon with oxygen, returning the Carbon dioxide to the atmosphere. In this way, the use of biomass boilers is carbon neutral, with no net greenhouse contribution, apart from fuel movement. If the biomass boiler replaced a gas or coal fired boiler, there will be a carbon dioxide saving by operating the boiler.
What space is required and how does it work?
The space required for a biomass boiler is much larger than a comparable gas boiler, mainly due to fuel storage and management and also space for exhaust treatment. Biomass is generally first chipped or ground into manageable sized pieces and then stored in a hopper or silo ready for use in the boiler. An automated system then moves the fuel into the boiler burner, which dries it, combusts it, and the boiler section generally uses the heat to create hot water or steam. The exhaust then moves to a multi-cyclone air cleaner, and to a variable speed fan to expel the exhaust through a flue. Boiler waste such as ash and collected particulate carbon is disposed of separately.
What are the applications?
The most common application is for steam generation at sawmills for kiln drying green timber. That said, any facility that has a reasonably dry waste product such as wood chips, nut shells, or grape marc that also requires heat can use a biomass boiler. Additionally, if there is a heat intensive industry close to a sawmill or alike, the industry can purchase waste biomass from the producer to create a mutually beneficial arrangement.
