Where does woody biomass come from?
The most common source of woody biomass fuel comes from sawmills that chip wood as a by-product. Heating system operators generally prefer mill chips because of their size uniformity as oversized pieces can potentially jam machinery. Other woodchips come directly from harvesting operations in the woods. Mobile chippers turn diseased and other “cull” logs into chips, while most of the tops and branches stay in the forest to return nutrients to the soil. While woodchips produced by this method are less uniform in size, they usually are significantly lower in cost. A third source of wood-based biomass comes from the waste stream of the forest products industry such as furniture manufacturers; however, manufacturing wood wastes are often used by the plants that produce them, and are less likely to be available for purchase by energy users. In addition, institutional users tend to avoid dry wood because it comes with more dust and a higher level of fire risk. The municipal waste stream can
