廃棄物エネルギを用いた循環型社会に向けたLCA解析モデルの構築: 日本における過疎地(地方山間部)での解析例

Abstract

Power generation systems using waste biomass have attracted attention. Such a system can convert waste biomass, which is discharged from residential areas, into power based on the local energy demand. By applying this biomass energy conversion system, we expect to improve the energy independence of a local society. However, since waste biomass, such as paper, scrap wood, and other garbage, has different thermal properties, it is desirable to process them for gasification. In addition, biomass has a low energy density, due to low volume spread over wide areas, the process requires waste transportation and accumulation, and therefore a large amount of energy. Hence, the implementation of these systems into local societies needs a prior and careful evaluation using Life Cycle Assessment (LCA). This study shows the usefulness of the evaluation using LCA by demonstrating a model city employing a waste energy recycling system. We evaluated the effects of processing speed of gasification, fuels of boilers and heaters on the energy balance, CO2 emission, and the total cost in the modeled rural city in a mountainous region. The analysis showed that the energy independence and CO2 emission can be improved by the use of a carbonization gas.