The research examines long-term feasible scenarios for CO₂ reductions both in the electricity sector and in each utility in Japan. In order to analyze the scenarios, we set several CO₂ reduction targets for the electricity sector in 2030. This paper looks at the combinations of CO₂ reduction strategies using a multi-regional optimal generation planning model. The model seeks configurations for both power plant capacities and their outputs under the objective of minimizing generation costs. The results show that promoting natural gas combined cycle power plants as newly-built options leads to the reductions of CO₂ emissions in 2030 to 90 Mt-C as compared to 137.9 Mt-C in BAU case. Marginal reduction costs for this scenario reaches 1,245 JPY/tC. Although CCS options for gas combined cycle permit additional cuts in electricity sector CO₂ emissions, the utilities reserve those options until just before the target year due to their high capital costs. In such scenario, the marginal cost increases to 20,440 JPY/tC.

抄録全体を表示

We constructed the model to evaluate the distributed energy supply network system of urban district and evaluated the practical urban district in Japanese middle city, Utsunomiya. Using this model, it is possible to deduce the energy saved plan under the condition of energy exchange among buildings and houses of the district.
We carried out the case study in the actual urban district and examined the possibility of energy saving and CO₂ reduction. From the GIS data, we can calculate the floor space and building space, using the model to estimate the energy load of building, and calculated the whole energy load of the urban district. Under these conditions, we evaluate the three cases, case 1; Installed cogeneration system in each building, case2 ;Installed cogeneration system in each building and energy interchange with houses, case3; installation of CGS and energy transportation network under the minimization of electricity sale from the district.
The evaluate results show the installed capacity and operation conditions, considering the surplus electric power of photovoltaic power and cogeneration. And the case of energy interchange with houses shows the energy consumption and is reduced over around 2% to case 1.

抄録全体を表示

After installing a photovoltaic (PV) system in a house or a school, it is said that people seem to increase environmental behavior such as electricity-saving. Do characteristics of PV systems have any influence on the change in people’s environmental behavior? This study attempts to discover why people’s behavior toward energy and the environment change after installing PV system in houses. Based on questionnaire surveys, this paper describes the results of statistical analysis concerning the changes in households with PV systems installed. The results show that, in households where the family members are highly aware of their PV systems, they tend to increase environmental behavior after installing the PV system. Moreover, it is found that the increase in the communication about environmental behavior in a family tends to go hand in hand with the increase in environmental behavior. The findings suggest that the installation of residential PV systems affect people's concern and norms related to energy and the environment, and then change people's behavior.

抄録全体を表示

To investigate pyrolysis behavior of wood biomass, laboratory scale experiments of pyrolysis about several kinds of wood were carried out by thermo balance and Curie point pyrolyser. And also, laboratory scale two stage gasification were carried out about apple tree to evaluate effect of fresh or old alumina and activated alumina. From the results of laboratory experiments, first, CO₂ was produced, then CO was produced over 200℃. CH₄ was produced at temperature range 300℃～ 700℃ mainly. H₂ was appeared over 500℃ and the maximum peak was found at the temperature range 700℃～800℃. From the results of laboratory scale two stage gasification, it was found that the activated alumina had reduced the amount of tar and increased the amount of H₂ gas.

抄録全体を表示

As rice cropping is traditional and sustainable agricultural system in Asia, utilization of whole rice crop has great potential for constructing biorefinery system. In order to produce bioethanol from rice cropping, it is a prerequisite condition that the energy balance of the system is positive. This study analyzes the energy balance of bioethanol production system from high yield rice in Japan. Two systems are considered and rice is converted to ethanol in both systems; one where cellulose feedstocks, straw and husk, are used for cogeneration (S-1) and the other where they are converted to ethanol and byproduct lignin is used for cogeneration(S-2). Energy input in agricultural process is estimated to be 4.8GJ/10a by I/O table. The heating values of produced rice and cellulose feedstocks are 12.0GJ/10a and 16.2GJ/10a, respectively. The energy balance of S-1 is 12.9GJ/10a, which produces 358L/10a of ethanol and 942kWh/10a of external electricity. The energy balance of S-2 is 1.2GJ/10a, which produces 707L/10a of ethanol. Both energy balances are positive and the energy balance of S-1 is much higher than that of S-2. However the energy balance of S-2 can be improved by utilization of other industry waste heat and/or development of energy saving technology.

抄録全体を表示