Example of Cascade Utilization

Biomass is considered as a substitute for fossil fuels, however, it is not economically feasible to produce energy from fresh harvested wood due to its high labor and infrastructure costs (Haberl, 2000). Therefore, it is essential to consider other strategies such as cascade utilization to utilize the biomass sources in a more efficient manner. According to Sirkin and Houten (1994), cascade utilization is a ?method for optimizing resource utilization through a sequential use of remaining resource quality from previously used commodities and substances?. In other words, cascade utilization of biomass such as wood is a sequential use of wood for material and chemical production, and energy generation. It can extend the utilization time of wood and improve its economy.

Figure 1: Example of Cascade Utilization

Figure 1 shows an example of a complex wood flow through the cascade chain for the material, chemical and energy sectors. The by-products from forestry or sawmill industry can be utilized through recovery or recycling process and mixing with other industrial wood residue for manufacturing of wood-based product in material, chemical and energy sectors.
By-product utilization is a process of recycling of a secondary product derived from a manufacturing process or chemical reaction. In wood industry, 10 % of harvested wood for log and 45 % of sawed log for timber production are formed as forest and industrial residue wood that can be recycled for further uses (WPC, panel board and etc).