Due to the intermittent generation of renewable energy sources, large integration of renewable energy sources tends to cause frequency stability problems in power systems. The utilization of electric vehicles (EVs) is considered to be one of the most prospective solution in frequency regulation especially in load frequency control (LFC) domain because of the fast-response characteristics of the EV batteries. However, the EV aggregators (EVA) participating in LFC regulation market may suffer from communication delays caused by the open communication infrastructure. In this paper, a control method is designed to compensate the communication delays for EVAs in order to improve the performance of frequency regulation capability of EVs. In a power system which applies Flat Frequency Control (FFC), the proposed method estimates the relationship between the LFC control signal and the frequency deviation in the system from historical data and control the EVs directly through the real-time frequency deviation. The implementation cost is small, and EVAs are expected to be more competitive in the frequency regulation market. The performance improvement is tested by dynamics simulation on ACG30 model in Simulink and evaluated based on a performance score. The performance score of EVA increased significantly in the simulation, and the system frequency fluctuation can also be reduced by applying the proposed control method.

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To reduce CO₂ emissions in the residential sector, the installation of high-efficiency energy supply equipment and the development of smart residential buildings are progressing. It is important to appropriately select energy system configuration, such as the number of installing equipment and capacity, for rational energy use. The purpose of this study is to analyze the trends of the relationship between optimal configuration and household characteristics. After that, we evaluate and analyze the derived configuration from a long-term perspective. We assumed the smart residential building consisted of 50 dwelling units, installs photovoltaics and battery as shared assets, and can power-sharing. Also, we assumed each household must install any one of 3 types of thermal equipment, which is a gas-fired water heater, heat pump water heater (HPWH), and solid oxide fuel cell cogeneration systems (SOFC). As a result, all the households select HPWH after 2025. Focusing on the number of occupants, the increased tendency to install HPWH before 2025 correlates with the number of occupants. In the long-term evaluation, the system configuration consisted of 35 HPWH and 15 SOFC is best from the viewpoint of CO₂ emissions. The configuration can reduce 21.9 % CO₂ emissions from 2020 to 2030.

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This paper presents the important economic factors of the biojet fuel pathway based on sensitive analysis of Techno-economic analysis in Japan. Biofuel is made from sustainable sources and it’s chemical elements are similar to those of kerosene with hydrocarbons from C8 to C18. It can be used in existing jet engines without any modification. Three pathways, gasification and Fisher-Tropsh synthesis (gasification-FT), Alcohol to jet (ATJ) and microalgae have been investigated by sensitive analysis of Techno-economic analysis. These results indicated that the biojet fuel price is very sensitive to production scale in case of all three pathways. In case of gasification-FT and ATJ, the collection of large amount of feedstock in one place is critical. In case of microalgae, a large area of tropical or subtropical site suitable for cultivating microalgae have to be prepared.
Furthermore, the perspectives of research, development and production of biofuel in Japan will be discussed based on the results of sensitive analysis.

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This paper proposes a CO₂ reduction surcharge which is charged proportional to customers’ CO₂ emission, instead of FIT surcharge proportional to the grid power consumption. When this new surcharge is slightly over 10,000yen/ton-CO₂, the operating unit cost of coal fired plants is over that of LNGCC plants, and the capacity factor decreases as well as CO₂ emission. Authors simulated a power system in 2030 where a large amount of PV is implemented and the 18% of PV generated energy must be curtailed. The annual cost is minimized by optimizing LNGCC and battery energy storage systems (BESSs) capacity, hourly output of coal fired and LNGCC plants, hourly charge and discharge power of BESSs, and PV curtailment. Results show this surcharge is effective to change fuel and decrease CO₂ emission, and BESSs moderate this fuel change but decrease PV curtailment and CO₂ emission. The energy chain including whole power system, demand and fuel is analyzed to see the power flow and CO₂ emission. It is also discussed to apply this surcharge to every fossil fuel usage in order to realize the almost CO₂ free society with a reasonable cost increase.

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