Cost and Greenhouse Gas (GHG) Emission Analysis of a Growing, Harvesting, and Utilizing System for Willow Trees Aimed at Short Rotation Forestry (SRF) in Japan

抄録

A system for growing, harvesting, and utilizing willow trees aimed at short rotation forestry (SRF) was designed in northern Japan, and the system was evaluated from the viewpoints of cost economy and greenhouse gas (GHG) emission based on a life cycle assessment (LCA) method. The willows were assumed to be grown intensively in 200 ha of idle land in the test area, harvested using a sugarcane harvester, and utilized for heat energy through the burning of wood chips directly in a biomass boiler. As a result, the cost of willow was 180.64 US$/dry-t, which was more than the cost of forest biomass such as logging residues and thinned trees, while willow chips were less expensive than heavy oil in terms of their price per calorific value. On the other hand, the GHG emission of willow was 6.633 kgCO₂eq/GJ, less than one-tenth that of heavy oil. Therefore, it is suggested that substituting willow chips for heavy oil as a heating fuel could be economical and could help reduce regional GHG emissions.