Sourcing fuel for industry
The majority of industrial wood fuel use happens when the wood processing industry uses its own residue (e.g. using sawdust and bark for kiln drying lumber). This is because it is easiest and most cost effective to source wood fuel on-site. However, wood fuel can also be sourced from external sites if needed.
On-site fuel collection is the most cost effective and makes it easier to control issues such as fuel quality and contamination (e.g. from soil). The type of wood collected impacts its suitability for use as fuel.
A typical breakdown of sawmill wood waste is:
- 5% bark
- 10% green sawdust
- 5% dry shavings
- 2% off-cuts
Dry sawdust can be a good clean fuel with very low ash content (about 0.5-1%) if handled correctly.
Wet sawdust can also be used but it burns less effectively and needs specialised burning technology.
Bark typically has a low moisture content which makes it a good fuel. However, it tends to be dirtier than other wood which produces higher ash levels that can cause problems when it’s burned.
Dry wood shavings are the most efficient wood fuel and are usually very clean and produce low-ash levels. However, they are very low density and may require specialised conveying systems and large storage facilities which can be costly.
Most chemically treated timbers can not be used as fuel because emission standards do not allow them to be burned.
External fuel sources
Wood fuel can also be sourced from external wood processing sites and forest residue collection operations. However, the quality of this fuel can be difficult to control and transport costs make it less cost effective to use than material sourced on-site. The availability of external fuel also varies by region.