6.1 Physical processing

Wood is not the most convenient fuel, but chipping it produces a more homogeneous material that is easier to handle in bulk. Further processing can form the material into consistently sized pellets that can be bagged for retail sale, or transported in bulk.

Systems have also been developed for producing high density pelleted straw, which allows boilers to be fed automatically, and transport and storage costs to be reduced.

The oil in crops such as rapeseed, soya and oil palms is contained within the seed. The oil has to be separated from the surrounding tissues, either by pressing or by using a solvent that dissolves the oil, making it easier to separate from the remaining material.