Raw materials that can be used to produce biomass fuels are widely available across the UK and come from a large number of different sources, and in a wide variety of forms. All of these forms can be used for fuel production purposes, however not all energy conversion technologies are suitable for all forms of biomass.
Raw biomass typically has a low energy density as a result of both its physical form and moisture content. This makes it inconvenient and inefficient for storage and transport, and also usually unsuitable for use without some kind of pre-processing.
There are however a range of processes available to convert it into a more convenient form. Depending on the biomass itself, and the purpose to which it is to be put, this may consist of:
In this way raw biomass is converted into what can be described as a 'biomass fuel'.
For example, virgin wood (above) is a simple form of biomass and for many applications may require relatively straightforward processing. For ease of handling, transport and storage it may be cut into a number of physical forms, as best suit the requirements of the next handling or processing stage.
Different classes of biomass fuel have different characteristics such as moisture content and size. These characteristics can be affected by transportation and storage.