Along with the electrification of vehicles, the sector coupling of electricity and transportation is progressing and demand response using electric vehicles is becoming more important for further effective use of renewable energy. The aim of this paper is to analyze the feasibility of demand response using electric buses in the market price-linked contract. Most of the previous studies on demand response using electric vehicles have focused on consumers, and there have been few studies on buses, which are considered to have less uncertainty and are easier to manage. To analyze the effectiveness of the market price-linked contract for promoting demand response in electric bus operations, the operation, annual costs for the bus operator, and revenues for the retailer are compared for the conventional fixed price contract case and the market price-linked contract case. The results show that the market price-linked contract is more effective in promoting demand response and making the profitability of retailers more stable. This paper shows some possibilities for electric buses to join demand response programs in the future.

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Due to the massive introduction of renewable energy sources, various impacts on the power system are anticipated, including supply-demand imbalances, congestion in the transmission network, decreased inertia, difficulties in voltage management, and reduced short-circuit capacity. A comprehensive assessment of these effects will be necessary in future power systems. In this study, we have developed a method for creating the future grid model of power flow calculation and transient stability analysis considering the uncertainties of renewable energy output and electricity demand, by integrating the weather reanalysis data (ERA5), and the transmission system network model and generation dispatching calculation model of synchronous generators including unit commitment (UC) and the economic load dispatch (EDC). The modeling of renewable energy output uncertainties is conducted by combining the assumable future renewable energy capacity aggregated at each substation and reanalysis data from ERA5 which is closest to the substation. As for the modeling of electricity demand, the climate-sensitivity model of electricity demand is established by the actual data of temperature and area demand. This paper also shows the typical results of power flow calculation and transient stability analysis of future grid model, which describe the difference of grid stability due to the condition of supply and demand of the grid.

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In apartment buildings (APBs), occupants are members of APB communities and live together. Occupants use individual spaces and share common facilities in the APBs. The power demand of APB is more complex than single-dwelling houses. However, a conventional management system has focused on a single residential space or a single building, which cannot consider a complex relationship built by the APB community. Therefore, based on an agent-based model, a unified home energy management system (U-HEMS) using various reward systems for the residential community is proposed to manage the power demand of the APB by considering individual satisfaction and fairness of the residential community. To assess the performances of U-HEMS using various reward systems, 100-dwelling APB was prepared for four cases: no, two-step, linear, and complex rewards. The results suggest that the household satisfaction and fairness of the residential community can be improved by the proposed reward systems integrated into U-HEMS. Based on the results, findings reveal that the reward system of the U-HEMS mediates the individual household demands in the APB community to improve overall household comfort.

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When using offshore wind power generation in offshore waters with good wind conditions, the cost of mooring the power generating float becomes high in deep waters, which is a practical limitation for commercial use. To solve this problem, we are considering a new wind power generation system that combines kite power generation and a mooring-less float. In this paper, we report on our attempt to create a conceptual design based on a qualitative understanding by constructing a performance evaluation simulation for a mooring-less wind power generation float.

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Electricity retailers procure electric power by combining multiple methods strategically. If they select Demand Response　(DR) using Virtual Power Plant(VPP) systems as their procurement means, it is expected to reduce purchasing volume from wholesale electricity market and shift those for arbitrage. We studied estimation methods to reduce the impact of forecast errors in electricity consumption on DRs and the effective approaches for battery level management. In simulations of VPP system using these methods on 80 houses, we confirmed that the response error was within 10% on average. It was also confirmed that the error could be kept within ±10% in 90% of the DR cases when 0.1 kW per customer can be supplied. Moreover, we verified the equivalent accuracy in a demonstration experiment using three houses.

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Research on energy management systems for microgrids up to recent years has covered a wide range of time scales, equipment, and services. However, the roles and purposes of consumers and aggregators targeted in these studies are scattered, making it difficult to apply them to the actual construction of microgrids. This study comprehensively deals with these studies and proposes a scheme that can be applied to microgrid construction plans. The proposed scheme consists of a long-term planning stage that considers an outlook of up to renewable energy 100%, a stage that considers various roles and performs capacity design at the same time as annual planning, and a stage that emphasizes short-term operational planning that considers various equipment. This paper demonstrated the use of the proposed scheme and visualized various indicators such as capacities and schedules to facilitate discussion between each role in the microgrid construction plan.

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This study investigates the motivations, initiatives, and challenges of companies in industrial sectors aiming for decarbonization through questionnaire surveys and interviews. The research highlights the roles and challenges of the supply chain engagement. It reveals that, as intrinsic motives, a high percentage of the respondents were already motivated by reduction of energy costs, interest in the SDGs, and enhancement of corporate image, followed by the link to profit-earning opportunities. As extrinsic motives, a high percentage of respondents were already motivated by requests from suppliers, increased consumer awareness, and compliance with regulations and systems. Moreover, it revealed that challenges such as lack of information and human resources, hidden costs, and uncertainty are hindering efforts toward decarbonization. One key challenge identified is the uncertainty regarding the attitudes of business partners for decarbonization. The study suggests that supply chain engagement can help mitigate this uncertainty, facilitating more effective decarbonization efforts. The findings underscore the importance of strategic supply chain engagement in achieving decarbonization goals in industrial sectors.

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As a measure to avoid suppressing the output of renewable energy, “demand response” (DR) is expected to be used for household electricity as well. However, in Hokkaido, the demand for heating is high and most of the heating is done using fossil fuels, so current heating methods cannot support DR. We thought that if we replaced this heating method with a hybrid heater that can use both electricity and gas, we could see the spread of DR in Hokkaido. This time, we verified the possibility of responding to DR using a household hybrid heating, cooling, and hot water system that can freely switch between an electric heat pump heat source and a gas heat source. As a result, we found that it was possible to secure a certain amount of raising/lowering DR control width, and we have confirmed that this system can be used to contribute to the realization of carbon neutrality, so we would like to report this.

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As a social application of the power to gas (P2G) system, we envisioned a system that uses renewable energy, which is ubiquitous in the region, to satisfy the medium-scale heat demands of local businesses. Therefore, the feasibility of using an engineering numerical calculation model was investigated. In addition, the potential medium-scale heat demand for a region was estimated using questionnaire information on energy consumption statistics. Based on the engineering numerical calculation model, it was found that the minimum unit cost of hydrogen production is approximately 66.2 to 128 JPY/Nm³, which is higher than the price of hydrogen parity for various applications. However, if the active use of unused renewable energy and sharing of hydrogen production equipment are considered, the hydrogen production price could approach parity price. Furthermore, from a macroscopic perspective, the potential of a region's surplus solar power is likely to cover the medium-scale heat demands of local businesses in the region. According to aggregated energy consumption statistics, there was a particular desire to develop a general-purpose P2G system that could be used in the medical, welfare service, and food manufacturing industries.

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