4:15 PM - 4:30 PM
[MZZ48-09] Development of a model for estimating future woody biomass utilization based on population change
Keywords:Sustainable energy, Woody biomass, Estimating model
In recent years, the number of woody biomass power plants in Japan has been increasing year by year. However, as of January 2020, facilities that use wood chips and palm coconut shells imported from abroad as fuel account for more than 60% of the total installed capacity of woody biomass power plants operating in Japan, and 90% of the certified capacity of woody biomass power plants certified under the feed-in tariff system. The use of domestically produced woody biomass resources for power generation is limited. While the use of foreign wood has the merit of providing a large amount of energy source at a low cost, there are concerns about price increases and the impact on supply stability due to the unsettled situation outside of Japan, like the two oil shocks that occurred in the past. Therefore, it is necessary to examine how much energy can be covered by woody biomass energy in Japan. It is also estimated that Japan's total population in 2050 will decrease by about 20% from the 2015 level due to a declining birthrate and aging population. Therefore, it is necessary to estimate the future in account of the decrease in population and, consequently, in energy demand.
In this study, in order to clarify the use of woody biomass in existing woody biomass power plants until 2050, which is the target year for carbon neutral initiatives, we estimated the number of resources and energy demand, and evaluated the economic efficiency and environmental impact of using woody biomass for energy. Life cycle cost (LCC) and life cycle CO2 (LCCO2) were used as the evaluation index of economic efficiency and environmental impact, respectively. LCC and LCCO2 are the total cost and CO2 emissions, respectively, for the entire product/service life cycle, from resource extraction to disposal. The system boundary was defined as the post-construction phase, from the time of construction of the power plant, through its use, to its disposal.
The study area was the whole of Hokkaido except for remote islands. Hokkaido has the largest forest area among all prefectures, and there is an abundance of woody biomass generated by thinning. In addition, there are four power plants with a rated output of 2,000 kW or more in Hokkaido that are designed to use wood from the prefecture. Therefore, this study assumes the use of woody biomass (forest thinning, scrap wood and waste wood from sawmills, construction waste wood, pruned branches of fruit trees, and pruned branches of parks) in these four woody biomass power plants.
In this study, a mesh of 1 km each in length and width was created in the Universal Transverse Mercator Coordinate System, and the amount of woody biomass resources in each mesh was estimated in terms of lower calorific value (MJ/year). In addition, the cost (JPY/year) and CO2 emission (CO2/year) of biomass utilization for each mesh were calculated. The selection of the amount and location of resources to be used was based on the constructed model. The model assumes that the resources are utilized in order of the 1 km mesh with the lowest cost per calorific value (JPY/MJ), which is obtained by dividing the resource utilization cost by the lower calorific value. The cumulative cost and CO2 emissions were calculated when the cumulative calorific value of the resources to be used exceeded the total calorific value of the resources required for power generation at each power plant. The total calorific value of the resources required for power generation at each power plant was calculated by multiplying the electricity demand in Hokkaido by the ratio of the output of woody biomass power plants to the output of all power plants in Hokkaido and dividing this value by the power generation efficiency of woody biomass power plants. The future heat requirements of power plants were estimated by multiplying the heat requirements of woody biomass power plants in 2020 by the population ratio. The language used for the model was Python 3.8.12.
In this conference, we will explain the details of the model and present the results of future estimation, obtained by the model.
In this study, in order to clarify the use of woody biomass in existing woody biomass power plants until 2050, which is the target year for carbon neutral initiatives, we estimated the number of resources and energy demand, and evaluated the economic efficiency and environmental impact of using woody biomass for energy. Life cycle cost (LCC) and life cycle CO2 (LCCO2) were used as the evaluation index of economic efficiency and environmental impact, respectively. LCC and LCCO2 are the total cost and CO2 emissions, respectively, for the entire product/service life cycle, from resource extraction to disposal. The system boundary was defined as the post-construction phase, from the time of construction of the power plant, through its use, to its disposal.
The study area was the whole of Hokkaido except for remote islands. Hokkaido has the largest forest area among all prefectures, and there is an abundance of woody biomass generated by thinning. In addition, there are four power plants with a rated output of 2,000 kW or more in Hokkaido that are designed to use wood from the prefecture. Therefore, this study assumes the use of woody biomass (forest thinning, scrap wood and waste wood from sawmills, construction waste wood, pruned branches of fruit trees, and pruned branches of parks) in these four woody biomass power plants.
In this study, a mesh of 1 km each in length and width was created in the Universal Transverse Mercator Coordinate System, and the amount of woody biomass resources in each mesh was estimated in terms of lower calorific value (MJ/year). In addition, the cost (JPY/year) and CO2 emission (CO2/year) of biomass utilization for each mesh were calculated. The selection of the amount and location of resources to be used was based on the constructed model. The model assumes that the resources are utilized in order of the 1 km mesh with the lowest cost per calorific value (JPY/MJ), which is obtained by dividing the resource utilization cost by the lower calorific value. The cumulative cost and CO2 emissions were calculated when the cumulative calorific value of the resources to be used exceeded the total calorific value of the resources required for power generation at each power plant. The total calorific value of the resources required for power generation at each power plant was calculated by multiplying the electricity demand in Hokkaido by the ratio of the output of woody biomass power plants to the output of all power plants in Hokkaido and dividing this value by the power generation efficiency of woody biomass power plants. The future heat requirements of power plants were estimated by multiplying the heat requirements of woody biomass power plants in 2020 by the population ratio. The language used for the model was Python 3.8.12.
In this conference, we will explain the details of the model and present the results of future estimation, obtained by the model.