Discussion on Economic and Energy Balances of Forest Biomass Utilization for Small-Scale Power Generation in Kanuma, Tochigi Prefecture, Japan

Nacrtak In this study, the economic and energy balances of forest biomass utilization for small-scale power generation are discussed, considering the spatial distribution of the forest biomass resources using the geographic information system (GIS) in the Kanuma area of Tochigi Prefecture, Japan. First, the optimum scales of two power-generation plants are discussed. For a direct combustion power-generation plant operating at an optimum scale of 5 MW generation capacity, the electricity cost would be 23.7 yen/kWh. For a small-scale gasification power plant operating at an optimal scale of 2.4 MW generation capacity, the electricity cost would be 12.8 yen/kWh. As the average electricity price in Japan is 22.2 yen/kWh, the electricity generated from the small-scale gasification power-generation plant could be economical. The energy balance and CO2 emissions from the energy utilization of forest biomass resources were analyzed using the life cycle inventory (LCI) method. For both types of power generation, the ratio of energy output to input was calculated to be about 20, indicating that the system examined in this study could be feasible as an energy production system. The CO2 emission from the direct combustion power generation with a generation capacity of 5 MW was 754.9 tCO2/year, while the CO2 emission of the small-scale gasification power plant with a generation capacity of 2.4 MW was 381.9 tCO2/year. However, the reductions in the amount of CO2 emission that would result from replacing fossil fuel were 15,707 tCO2/year and 6,275 tCO2/year, respectively. 1 = 114 yen on June 27, 2011.