In recent years, many coffee chain stores have opened nationwide, and it has become possible to drink drip coffee easily and inexpensively at major convenience chains. However, there is a problem that a large amount of waste is left behind after the extraction of coffee. In this report, in order to solve the problem of coffee grounds in small and medium-sized coffee beverage factories, we examined the energy cycle of processing coffee grounds into Bio-coke and using it as a heat source. Bio-coke is a biomass solid fuel that can be molded from various biomass feedstocks. With a relative weight yield of 100%, its volume can be reduced and it can be stored for a long time. In addition, the manufacturing process is simple and suitable for small-scale distributed use. As a result of examining energy circulation systems that use coffee grounds Bio-coke as heat sources for drying coffee grounds and roasting coffee beans, we have found that this system is feasible. The coffee grounds used in this study had a water content of 70 wt.% before drying and a water content of 2.0 wt.% after drying. Assuming that the low calorific value of 1.0 kg of coffee grounds Bio-coke is 100%, the proportion of each energy required to make 1.0 kg of coffee grounds Biocoke is as follows. The thermal energy required to dry the raw material moisture was 58.6%. The electrical energy useed to heat and compress the coffee grounds to produce Bio-coke was 8.0%. As a result, it was found that 33.4% of the energy of coffee grounds Bio-coke can be used effectively. If 13.1% of the energy is used to roast coffee beans and 0.1% is used to transport coffee grounds Bio-coke, the remaining 20.2% can be used as heat energy for the extraction plant.

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This paper presents the effect of changes in meteorological conditions in a study on the feasibility of greenhouse gas (GHG) reduction by 80% in Japan toward 2050. The authors develop a bottom-up energy system model which incorporates a high-temporal-resolution power sector and analyze the feasibility under 18 patterns of variable renewables’ (VREs’) power profiles. Simulation results show that the changes in meteorological conditions, namely the duration of sunless-and-windless period would substantially impact the installed capacity of electricity storage systems. Since the capacity may differ by as much as 300 GWh in 2050, considering several VRE power profiles would be essential when studying future massive decarbonization where VRE is expected to account for more than 50% in power generation mix. Although the effect on the degree of electrification and the technology choice in the final demand sectors by the changes in meteorological conditions is relatively small, the minor difference may lead to huge variation in GHG marginal abatement cost.

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In this paper, we develop a dynamic multi-sector energy economic model that takes into account the difference in the automobile industry, the production cost, and the fuel consumption due to vehicle types or engine types. In the previous research, an economic model is developed considering the inter-industry linkage of the electric power sector and the material industry. The novelty of this paper is the point that newly considered the automobile industry. This paper evaluates the impact on the economy and energy supply and demand due to the structural changes in automobile industry such as spread of next-generation vehicle (NGV) in an integrated viewpoint from the economics and the engineering. Simulated results show both positive and negative effect of structural changes on industries and implies that the spread of NGV, the appearance of car sharing service and the charge and discharge of electric vehicle to power grid do not always have a positive effect in the society as a whole. This research enables further and more comprehensive analysis of the automobile industry.

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Food is essential for human life and its stable supply is important. However, it seems that there is room for suppressing the food wastage throughout our food system. This study focused on Japan, and estimated amounts of reductions in the energy consumption and GHGs emissions due to food wastage reductions. Our analysis based on an Input-output table shows that, if 50% of food wastage (F: agriculture for vegetables and fruits, I: food manufacturing industries, distributors, retailers, and eating and drinking industries, and M: household) is suppressed owing to the technologies such as advanced food demand prediction using weather forecast information, then, productions corresponding to the discarded food can be saved in many relating sectors, and the energy consumption and GHG emissions in Japan are reduced by 0.04～0.08EJ/yr and 5.9～8.4million t CO₂eq/yr, respectively. Furthermore, it is suggested that decrease in food wastage at the sector I leads to the GHG emissions reduction in Japan at lower cost compared to the decreases at the sectors F and M, since the latter may have issues on efficient transportations of mail order vegetables (normally non-marketable) or replacements of residual heat at incineration facilities.

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Recently, there is the largest (photovoltaic)PV-Hydro plant which has been set up as a utility-scale power generation in China. The purpose of this plant is to make the power grid accommodate more electricity from PV. In order to make more PV to be integrated into the power grid and expand its use, it is necessary to evaluate the relationship between PV and hydropower stations as hybrid stations. In this study, we have proposed an evaluation model based on cascade hydropower stations in China to estimate installation capability of PV for each reservoir, considering re-regulation volume and water supply relationship. The results indicate that the PV-Hydro power generation has a better effect on electricity generation during the day and night; PV installation on the upstream large hydropower station will affect the PV installation of the downstream small hydropower station and vice versa. However, the installation on the upstream small hydropower station will not have an effect on the one in the downstream large hydropower station; the maximum size of PV installation is 5926MW under constraints. Furthermore, applying PV-Hydro power generation has a better effect than applying them separately on reducing CO₂emissions.

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In this paper, a literature survey and an evaluation of the technological potential of electrification in industrial sectors in Japan were conducted. The ten largest energy-consuming sectors were selected and their electricity consumption was estimated assuming that electrification technologies are installed on a large scale. The estimation reveals that electricity consumption can increase by 93 TWh in total, mainly due to the wide diffusion of heat pumps in the production process, replacing the current boiler usage. This implies that there is considerable potential for heat pump technologies that are already practically implemented. It has also been demonstrated that there is potential to increase consumption by 646TWh through the use of direct and indirect electrification in a wide range of industries, including the iron and steel, and chemical industries.

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This paper described class practice of an energy learning guidance plan for next-generation traffic. This study specifically emphasized the transport sector from a perspective of energy and technology as teaching materials. The plan was to induce students to consider their lifestyle influence based on the latest technology. The author taught 105 high school students and collected worksheets. They reported decisions about next-generation vehicles, climate change strategies, and automatic driving levels. The author obtained diverse responses. Using a text mining approach, this study extracted sentences presented by two or more students from the worksheets. Students’ awareness of energy issues increased, as evidenced by cluster analysis results. This class enabled students to cultivate an interest in science and technology. Furthermore, some reported that they developed ideas about society while considering the environment. An important future difficulty is consideration of contents for sustainability. It is hoped that similar classes will be taught at many schools.

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