In Japan, the deregulation of the power sector and the on-going massive deployment of PV and wind are changing and will continue to change the demand and supply structure of the power system. New technologies and institutions are expected to work well in the various whole-sale power market to contribute to the decarbonization of the energy sector. The spot market, or the day-ahead energy market is the major market and we can value each new technology and institution using the spot market price, if they are estimated for the future. In this paper authors propose the Full-max cost in the demand and supply analysis as an estimator of the spot market price. The authors, providing the definition of the Full-max cost, verify the viability of the Full-max cost through the simulation of the historical JEPX spot market price of the fiscal year of 2019.

抄録全体を表示

This study focuses on household energy expenditure and prices, and clarifies the characteristics of household CO₂ emissions by region, energy composition pattern, and income class, based on the statistics of the Ministry of the Environment's survey of household CO₂ emissions. It was confirmed that lower income households in northern Japan have a greater burden on energy expenditure. In addition, the impact of energy price changes on demand is more limited for households in lower income and in northern Japan, indicating that the burden of energy expenditure due to higher energy prices is likely to increase. We analyzed the likelihood of an energy shift in the household sector, which is expected to reduce CO₂ emissions. The results show that substitution between electricity and non-electricity energy is more likely to occur in northern Japan and less likely to occur in western Japan. However, in northern Japan, the share of energy expenditure in the household budget is larger than in other regions, so encouraging electricity shifts through price effects could be a significant burden, especially for low-income households.

抄録全体を表示

Efforts for de-carbonization has accelerated in Japan. As result, full scale power sector analyses regarding the energy demand and supply structure needed for 2050 in Japan, to reach low-emission scenarios are being published. However, more studies are needed to explore the various possibilities of de-carbonization, including electrification, and mass introduction of CO₂-free generation and production. This paper presents a series of study cases, selected to reflect different deployment scenarios of photovoltaic power, wind and nuclear combined with scenarios of demand response by heat pump water heaters and electric vehicles. The results include future supply structures, generation shares, zero-emission generation surpluses, requirements for dispatchable generation, operational cost, and CO₂ emission of each case studied. From the results, it can be concluded, for example, that 400 GW of PV and 140 GW of wind can be effectively integrated into Japan’s electricity system, yielding a substantial reduction of CO₂ emission from the power sector, near to 42 million tons per year.

抄録全体を表示

This study performs model analyses assuming the Japanese power supply portfolio in 2050 to evaluate the optimal generation portfolios that contribute to both economic growth and low-cost power supply by in 2050. The energy model developed in this paper is an integrated model which combines an optimal power generation mix model and an econometric model.
Considering the economic ripple effect, portfolios that include zero emission power generation do not necessarily decelerate the economic growth, even if the portfolios raise the electric price due to higher system costs. A balanced energy mix using not only zero-emission power generation but also an optimal amount of gas power generation can realize the harmonization between the environment and economic growth.

抄録全体を表示

The need to limit climate change, which is an urgent challenge for global society, requires encouraging discontinuous innovations that will dramatically change our society. In line with the “Environment Innovation Strategy”, various companies and organizations are challenging innovations toward a decarbonized society. In order to promote collaboration between the companies and organizations for accelerating the creation of innovations, this study aims to structure innovation challenges towards a decarbonized society, by conducting text mining of “Challenge Zero” initiative by Keidanren (Japan Business Federation). Cluster analysis and correspondence analysis are performed to identify common keywords from the challenges and show the relationship between the keywords and industries. Correspondence analysis plots show that the keywords and industries can be classified into three categories: “electrification”, “energy decarbonization” and “finance”.

抄録全体を表示

Recently, in the field of mobility, car sharing services are expanding. Attention is also paid on increasing use of electric vehicles (EVs). In the field of energy, studies are being conducted on energy management using EVs. However, most of these are targeted at private cars and commercial cars, in which actual usage is fixed to some extent.
In this article, we focus on car sharing of EVs, which are difficult to know when they will be used and which are difficult to restrict the use of vehicles. Then, we aim to design a car sharing system and an energy management system with charge / discharge using EVs. In particular, this article describes the development of a preference model for car sharing vehicles and the operation results of the designed energy management system. As a result, it was found that users select a car, taking the volume of the car, the usage fee, and the type of car into consideration. By introducing model predictive control into the energy management system, energy cost could be substantially reduced, while SOC can be maintained at a high level, making it easier to respond to sudden reservations. It was shown that there is a possibility of further profit by increasing the charge / discharge speed.

抄録全体を表示

The introduction of electric vehicles has been placed as a countermeasure against global warming in the transportation sector, but there has been little consideration of the potential for electrification based on the operating conditions of vehicles for business pur-poses. This study shows the electrification potential of vehicles used in business and logistics and the nature of the charging infra-structure by simulating the movements of individual agents with the information obtained from the data on the origin and destina-tion of the 2005 National Survey of Roads and Streets Traffic Conditions (Traffic Census). The results show that most of all com-mercial passenger cars are able to be electrified. On the other hand, freight vehicles traveling a limited distance can only be electri-fied, even if the conditions are met that they can be charged with Origin and Destination. As electric vehicles become widespread, they will create a significant impact of demand for electricity if the timing of charging is not controlled. It is desirable to be able to charge at Destination as well, because not only provide peace of mind for drivers, but will also help to spread the load on the power system and make it easier to use renewable energy.

抄録全体を表示

This study attempts to assess the relationship between consumers’ awareness of environmental labels, such as the Eco Mark and their inclination for environmentally-conscious behaviors, including concern for the environment and energy-saving actions. The relationship between environmental label awareness and environmentally-conscious behaviors was investigated using multiple regression and logistic regression based on questionnaire survey data.
Results from multiple regression analysis showed that high environmental interest, efforts to reduce energy consumption, and aggressive registration for energy visualization services were positively related to environmental label awareness. It was also found that environmental label awareness was higher among men and the youth.
Results of logistic regression analyses for individual labels revealed that the degree of environmental interest, energy reduction efforts, and inclination to change power companies had a positive influence on environmental label recognition for all cases. However, the statistically significant explanatory variables were different for individual labels. For example, recognition of the low-emission vehicle label, an environmental label, was higher among men than women. From this study, we can conclude that it is important to devise information display for environment labels for various type of consumers.

抄録全体を表示

Fast Automated Demand Response (FastADR) is one of the expected measures to control electricity demand of consumers so that the balancing of electricity supply and demand in a short time horizon is improved. Due to their high power consumption in business buildings, Heating Ventilation and Air-conditioning (HVAC) loads are the promising resource for FastADR. However, because of their operational characteristics, HVAC loads do not perfectly follow external control signals. To mitigate this problem, Battery Energy Storage System (BESS) can be used complementarily. This paper proposes a method that coordinates the operation of building’s multi-units air conditioning system and BESS to reduce the required capacity of BESS for supporting HVAC operation in the FastADR. In the proposed method, the BESS discharges to supply the difference between the FastADR signal and HVAC load consumption and then recovers its energy by further adjusting the reference power consumption of the HVAC load, in which the thermal capacity of buildings is considered to reduce the required capacity of the BESS. Numerical simulations are performed to demonstrate the benefit of the proposed coordinated control.

抄録全体を表示

The demand of cobalt is surging largely due to the increasing use of Lithium-ion batteries (LIBs.) However, the supply chain of cobalt has been unstable. The production countries are very limited and most intermediate products are concentrated in China. Most existing research focused on the specific parts of the supply chain and didn’t cover the chain from cobalt mines to end-uses. This study aimed to understand the entire supply structure of cobalt being used as LIBs by using the social network analysis. We found out that the supply structure of cobalt had low robustness and resilience. More importantly, China and South Korea were successful in building the network for procuring cobalt, while Japan could not. Finally, it was concluded that the global supply structure of cobalt for LIBs was very fragile as a whole and Japan especially had the huge risk considering its demand for cobalt.

抄録全体を表示

This paper presents the result of examining the evaluation method of the energy value of electricity and heat output by cogeneration system. When purchasing electricity or heat from others, it is well established that the evaluation of their energy value is converted to primary energy in accordance with the provisions of the energy saving law in Japan. However, the evaluation method of electricity or heat output by a distributed energy system such as a cogeneration system has not been determined, and sufficient studies have not been conducted. This paper proposes to evaluate the electricity and heat of a distributed energy system from the three viewpoints of "calorific value", "origin value", and "alternative value". In addition, this paper proposes several new methods for apportioning the input energy of the cogeneration system to the output electricity and the output heat for evaluating the origin value. One of them is a method using exergy value.

抄録全体を表示