The small-sized energy supply system with hydrogen storage based on natural energy can be operated independently. However, estimating the system scale is not straightforward, as it requires a detailed assessment of the energy input from natural energy and the energy used. Here, we introduce a simple method of estimating the scale design guidelines for the energy systems with hydrogen storage based on local weather condition. Although detailed conditions are required for the actual energy system design, it is available to know the rough design of the system scale taking the local weather into consideration. From these analyses, it is found that local weather conditions have a large impact on the system scale.

Coffee residue (spent coffee grounds) has been unused biomass resources and discarded as food waste in a large amount. In this study, we aimed to develop all-biomass coffee residue products by wet extrusion molding with a natural molding aid. Coffee residue and hydroxypropylmethyl cellulose (HPMC) were mixed at a ratio of 8:2 to 5:5, water of 70 to 200% of the solid weight was added and kneaded, as a result, the coffee residue obtained fluidity. The amount of water has a great influence on the fluidity, and it was successful to extrude coffee residue into a plate or hollow shape with water of 100% of the solid weight. Unlike wood powder, the larger the ratio of HPMC was used, the higher the extrusion resistance, the lower the shrinkage and the Young's modulus of the molded products were. The difference in the components probably affected the characteristics because coffee residue has a low cellulose content and a large amount of oil and protein. It is epoch-making that coffee residue can be molded three-dimensionally without using thermoplastic resins with poor biodegradability. The products are possible to solve both the food waste problems and the serious environmental problems originated from plastics.

Reducing carbon dioxide (CO₂) emissions from energy consumption is an urgent requirement to address climate change. The difficulty for energy consumers to consciously perceive CO₂ emissions largely hinders the reduction of CO₂ emissions. The purpose of this study is to develop new indicators to help CO₂ emissions to be perceived intuitively and to show the applications of the new indicators. The main results of this study are as follows. (1) The authors introduce the new concept of CE (carbon-related energy) that shows a very strong correlation with CO2 emissions based on heating values and the element contents of fuels. The authors introduce CE-derived concepts such HE (hydrogen-related energy), RE (renewable energy), and CE ratio. (2) The CE ratio that is defined as CE per energy is the index of CO₂ emissions intensity per energy. The CE ratio that is expressed as a normalized index ranging between 0.0 and 1.0 would intuitively be perceived by energy consumers. (3) Using the modified Kaya identity that the authors derived using the CE-derived concepts, an increase and decrease in CO₂ emissions can be explained by the factors concerning CE-derived concepts and GDP. Using the CE-derived concepts, energy and CE as the indices of CO₂ emissions can be described in one unit in a table or a figure instead of separately.