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The enforcement of a feed‐in tariff (FIT) program in Japan has increased the number of installations of photovoltaic generation systems in its residential sector. After the end of an FIT program, the surplus electricity of an individual prosumer is purchased by the utility company at a reduced price, which may have an economic impact on the prosumer. To avoid this adverse effect, peer‐to‐peer (P2P) electricity transactions among prosumers based on blockchain and smart contract technologies as well as introduction of residence‐use stationary storage batteries are generating significant interest. In this study, the potential economic merit of P2P transactions and residential storage battery introduction are evaluated using a total optimization approach. For realizing a more practical perspective, this study also investigates the economic merit based on a partial optimization approach, in which an individual prosumer pursues its own profit. Furthermore, in this study, the grid‐side merit of P2P electricity transactions among prosumers is examined. Comparison of the merits determined by the total and partial optimization approaches shows that the realization of P2P transactions could provide a notable economic merit to the participants and reduce both the required facility capacity and power flow variation. © 2022 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Renewable energy (RE) sources like wind and solar power have been introduced to power systems to make the energy market more sustainable and environmentally friendly. For this reason, the supply-demand mismatch in power systems is more severe than before, in terms of both frequency and magnitude. It is therefore necessary to reinforce the capability to make supply and demand adjustments in power grids. Here, we clarified the dynamic characteristics of biogas plants with combined heat and power (CHP) systems, that represent controllable RE power sources, and evaluated the possibility of using these systems as a new resource for supply-demand adjustments in the power grid. Additionally, the properties of the exhaust gas from the investigated CHP engines were measured as an environmental evaluation. We considered real-world biogas CHP systems operating in both Germany and Japan. Based on the results, biogas CHP systems have the potential to contribute to a long-term power equivalent adjustment such as tertiary control reserve (TCR) in Germany. However, these systems required several minutes between starting and stopping. Furthermore, increased emissions of methane and formaldehyde were measured when the CHP systems were starting up. We found that an operation with as few starts and stops as possible is therefore desirable. • Evaluation of the dynamic characteristics of actual biogas CHP systems. • Investigation of load response with biogas CHP systems operating in Germany and Japan. • Analysis of load adjustment as well as start-up and shut-down behavior of CHP systems. • Measurement exhaust gas emissions during supply-demand adjustment. • Biogas CHP systems can contribute to long-term power equivalent adjustment. [ABSTRACT FROM AUTHOR]