Dynamic Simulation of Woody Biomass Co-generation System Considering Time-Varying Heat Demand: A Japanese Community Bathhouse Case Study

Since the implementation of the feed-in-tariff scheme in Japan in 2012, the number of Japanese power generation plants using woody biomass has been increasing. In order to maximize the amount of usable energy extracted from woody biomass, however, it is necessary to use the generated heat in a way that meets heat demand fluctuations. This paper proposes a model that enables the dynamic simulation of a woody biomass co-generation system, taking into account the balance of heat demand and supply. The model is developed using life cycle simulation to evaluate and compare different configurations of energy conversion systems from both economic and environmental viewpoints. A case study involving a community bathhouse in Nara, Japan was conducted using two scenarios: one in which only heat is supplied using conventional heavy oil, and a second in which both heat and electricity are supplied by introducing gasification combined heat and power (CHP) equipment using wood resources. A comparison of the two scenarios showed that CO2 emissions in the CHP scenario were 190% lower than those in the heavy oil scenario. Moreover, the cost of the CHP scenario was 23% lower than that of the heavy oil scenario due to electricity sales based on the feed-in-tariff scheme.