Other
Sawmill co-products
When round timber is processed through a sawmill it is only possible to convert a proportion of the log (typically between 40 and 60 percent) into a sawn timber product. The rest forms a co-product of the sawmilling process such as woodchips or shavings, sawdust, slabwood or other offcut material. There may be existing markets for these co-products, such as the use of sawdust for agricultural bedding, but they can also be readily turned into woodfuel by further processing (dry sawdust can be processed into wood pellets. Offcuts and slabwood can be processed into woodchips).
Arboricultural Arisings
The term arboricultural arisings encompasses all the material produced during arboricultural, or tree surgery, operations and can include stems, branches and leaf material. Often the arisings are chipped on site to waste or taken to land-fill sites. However, some of this material may be suitable for processing into woodfuel, most commonly woodchips, potentialy turning a costly waste material into a valuable product.
The key consideration for the arboriculturalist aspiring to supply woodfuel is in the logistics involved in the collection and drying of the available material, and in the delivery to the end user. Typically the raw material is sourced in many disparate locations, and often in small quantities, and the ability to efficiently collect and transport the material to a central location for processing is essential in making this source part of a viable supply chain.
Recycled Timber
A further potential source of woodfuel can be in recycled timer processed into woodchips or pellets. Timber can be recovered from a variety of sources including used pallets (1m tonnes currently in UK circulation), construction site waste, joinery offcuts etc.
To give an an idea of the scale of the potential resource, wood-based construction 'waste', as one example, totals approximately 18m tonnes per annum. Utilising some of this material for biomass is an ideal way of reducing landfiill and adding value to what may otherwise be a costly liability.
Things to consider when deciding whether recycled material is suitable for woodfuel include:
- Contamination: the material should not be contaminated with paint or other chemical products
- Metal content: all metal must be removed from the material during the processing as this can damage auger feed mechanisms and boiler grates