In this paper, a method to calculate electricity demand in the region based on scenarios regarding the future introduction of PV(photovoltaic system) and EV(Electric Vehicle) to the region were developed and were conducted trial calculations for Aichi Prefecture. The main findings are as follows: 1) Annual net electricity demand in Aichi Prefecture will tend to decline as the number of residences decreases and PV penetration increases; if only EVs are deployed as targeted by the government and PV penetration is slow, the decline will be moderate. 2) As of 2050, regardless of scenario, the demand curve will be duck-curved in Aichi Prefecture as a whole. This trend will be particularly severe during May holidays when electricity load is low, and net electricity demand will be negative in Aichi Prefecture if PV penetration is as high as the government target. 3) The impact on net electricity demand will vary by region, with a small impact in the central Nagoya area, but a larger impact in the suburbs, and an increase in the number of regions where net electricity demand will be negative, either temporarily or as an annual total.

Fuel cell cogeneration system has enough potential to control voltage fluctuations during day time. Hence, this paper presents a method for suppressing voltage fluctuations by controlling the reactive power output of fuel cell cogeneration system. The amount of reactive power for voltage control is decided based on the variation of the active power output of photovoltaic generation. However, the effectiveness of suppressing voltage fluctuations depends on conditions of the distribution system. In the method, the automatic gain tuning control is applied to generate appropriate reactive power for voltage control depending on conditions of distribution system. In the paper, the effectiveness of the proposed method to reduce the number of Load Ratio control Transformer operation for controlling voltage fluctuations is demonstrated by the simulation of distribution system model based on feasible cases.

The paper proposes a basic design of IEC 61850-based communication adapter consisting of a common module that performs majority of communication transformation processing and a custom module that primarily performs the modulating and demodulating of payload information specific to each legacy communication protocol. The paper also shows an evaluation result of the proposed 61850 adapter with its prototyping in functionality and performance.

With the massive deployment of variable renewable energy for achieving net-zero, the need for balancing capacity is increasing. This study proposes a market bidding strategy method which is used by an aggregator that manages DERs, to effectively utilize the value of power & energy supply (kWh) and adjustment power (ΔkW) of DER. The proposed method is based on a trade-off between imbalance loss and market profit. First, the weighted learning Similar Days method (SD method) is used to forecast market prices. Second, the imbalance risk is calculated based on the forecasted market prices, demand, and imbalance charges. At last, the bid volume is determined based on multi-factor value at risk (MVaR) constraints. The results of bidding simulations based on actual data such as market prices showed the effectiveness of the proposed method from the perspective of the total profit based on the trade-off of imbalance loss and market profit. We confirmed that the proposed method improves the profit compared to the conventional method.

Capacity market in Japan currently determines VoLL (Value of Lost Load) substantially and uniformly using reference procurement cost and target supply reliability, and can be regarded to be derived from a supplier's perspective. However, as seen in transactions of demand response (DR) in power markets, compensations of demand adjustment vary among DR suppliers. Therefore, deriving VoLL from customers' perspectives shall be more in line with reality.

This paper proposes a unique method to quantitatively assume VoLL of 12 industries based on revealed preference approach using actual energy consumption data of customers of each industries. This paper also proposes a new method to economically determine the amount of capacity procurement and the different levels of supply reliability of each customers, considering the variation of VoLL among customers and also the congestions of interconnectors.

Clarifying the supply reliability of customers not only encourages them to proactively introduce measures, but is also effective for paradigm changing to secure stable power supply reflecting both supplier and customer perspectives.

Towards carbon neutrality, microgrids (MGs) attract attention for the utilization of distributed energy resources including renewable energy sources. Since the scales and the structures of MGs heavily depend on their objectives and local requirements, interconnecting an MG to a distribution system in general increases uncertainty. To minimize the uncertainty, this paper adds a study of interconnection methods using a power-electronics converter in terms of protection and control. The power-electronics converter called an interlinking converter (IC) in this paper interconnects an MG to a distribution system via a common DC bus, and the MG and the distribution system are therefore electrically-isolated. This paper first presents an electromagnetic transient (EMT) simulation model of ICs. Then, a simulation case where an MG is connected to a distribution system via an IC is created, and the effectiveness of the IC interconnection method is demonstrated using the simulation case.

In recent years, wholesale power exchanges worldwide have begun to allow linked block order. In Japan, linked block order has been available since FY2024, with the expectation that it will eliminate concerns about missing contracts by power producers, increase the volume of sell orders by power producers, and consequently increase the volume of market transactions. Using multi-agent simulation, we examine the impact of the introduction of linked block orders in wholesale power exchange trading and the possibility of exercising market power in wholesale power exchange trading using multi-agent simulation. The simulation results showed the potential for opportunities to use linked block orders to exercise market power.

With the promotion of large-scale renewable energy introduction policies aimed at a carbon-neutral society (Net Zero) and the increasing risk of electric power shortages, it is becoming increasingly important to utilize the surplus capacity with adjustment capacity of consumer's distributed energy resources (DERs) in the market. To promote the active market participation of DERs in multiple electricity markets that are being developed in Japan, it is important to develop optimal bidding strategies for multiple markets. In this study, we consider multi-market strategy and propose the `two-stage bidding strategy method' for the wholesale electricity market (spot market) and the balancing market Tertiary-2 and evaluate the economic value from the resource owner's perspective based on actual market data. The proposed method deals with the spot market that trades the kWh value of DERs and the balancing market that trades the ΔkW value of DERs, and it is the optimal bidding strategy logic that considers differences in bidding times and market rules. In the proposed method, predicted highest contract price and optimal strategic parameter for bid price of balancing market are required. So, in this research, (i) prediction of the market price in the balancing market with several methods are comparatively evaluated, and (ii) strategic parameters for bid price to the balancing market are optimized based on the past market data. As a case study based on an existing DER, the overall market profit is evaluated from the bidding simulation with market data in 2021-2022FY, and some additional analysis and consideration was performed.

This paper introduces an overview of the large-scale hydrogen plant FH2R and the mathematical optimization of the operation planning function in the energy management system that manages the entire FH2R facility. The operational planning function aims to meet hydrogen demand while also addressing various types of DR.

Polygon thermal resistant aluminum conductors fiber reinforced (PLY-TACFR) conductors are expected to have lower electrical resistance, lower wind load, and lighter weight compared to conventionally used thermal resistant aluminum conductors steel reinforced (TACSR) conductors because of the changes in shape and core material. This study investigated the mechanical properties and snow accretion and vibration characteristics of PLY-TACFR in real environments, through full-scale field observations and experiments. Based on the results, PLY-TACFR was found to have a lower linear expansion and drag coefficient compared to TACSR. PLY-TACFR have larger torsional stiffness than TACSR in small rotational angle regions, leading to less snow accretion than for TACSR. Additionally, general countermeasures for snow accretion proved to be effective for PLY-TACFR. Furthermore, the galloping amplitudes were lower than those of TACSR due to smaller sag. These results indicated that PLY-TACFR are equivalent or higher to TACSR regarding basic mechanical properties and snow accretion and vibration characteristics in winter.

This study aims to quantify the amount of loss due to partial load of power conditioning system (PCS) and internal loss of storage battery in residential photovoltaic (PV) power generation and storage battery system by using home energy management system (HEMS) data. After identifying the configuration of the PV power generation and storage battery system, HEMS data on PV power generation, household demand, storage battery charging, storage battery discharging, purchased power and sold power were extracted and analyzed according to the research purpose. As a result, the loss due to partial load of the PCS and the average internal loss of the storage battery were quantified. In addition, it was confirmed that a more realistic system simulation could be performed by considering the impact of the partial load of the PCS and the average internal loss of the storage battery.

Surge arresters (SAs) installed on distribution lines to prevent lightning outage may fail when the energy of lightning current flowing into SAs exceeds their withstand capability. Although the previous research has been reported that the energy withstand capability of SAs decreases due to the repetitive flow of lightning currents, the influence of this decrement on the SAs failure rate has not been studied. In this paper, we assessed the failure frequency of the SAs considering the decrease of the energy capability of SA due to repetitive flow of lightning currents by means of lightning outage rate calculation program for medium-voltage distribution lines developed by CRIEPI.

Controllable load, such as hydrogen supplying equipment connected by a self-commutation type converter that can regulate active power, has been identified as alternative regulating resources to stabilize the power system which has a high penetration of renewable energy generation. The authors focus on frequency-watt control by a self-commutation type converter connected to a controllable load and have proposed a system for regulating active power. However, the load modeled as a controllable current source differs from the actual water electrolyzer load due to its static and linear characteristics. To reveal the controllability and economic efficiency of the system, this paper improves the system with a controllable load that has dynamic and non-linear characteristics is proposed. Moreover, the daily simulation using actual system frequency data, energy transaction data, and public offering regulation data verifies the compliance with the supply and demand reserve market requirements for primary frequency regulation capacity and evaluates the cost of hydrogen supply in the system.

As one of NEDO's international demonstration projects, a large-capacity hybrid battery storage system which consists of two types of battery cells with different charge-discharge characteristics was constructed in the state of Lower Saxony in the Federal Republic of Germany. By using the hybrid battery system has a lithium-ion which has an advantage in short time and high rate, and a sodium-sulfur battery (NAS) which has an advantage in long time and low rate, the tender participation in the balancing power market in Germany had been executed.

The hybrid battery storage system could successfully drive and provided services for primary and secondary control reserves, elimination of power imbalance, and reactive power injection, as well as a combination of these services.

We have developed and demonstrated the energy system for large-scale hydrogen plant FH2R. The control function in this system achieves hydrogen supply using renewable energy and various types of Demand Response. This paper shows the result of demonstration tests for Reserve Market by the control function.

Large-scale introduction of electric vehicles (EVs) puts an electric load to the power system. Recently, the capacities of on-board batteries and the outputs of quick chargers have been increasing. Increase in the battery capacity allows EV owners to charge more freely; however, charging may concentrate at a certain time such as on Friday afternoon, which is before the weekend, because EVs travel relatively long distance on weekends. Therefore, we evaluate an impact on the peak load in area mesh unit, assuming high power of quick chargers and the change in charging behavior. Charging threshold is defined as follows: when a state of charge (SOC) of an EV falls below the charging threshold, the EV goes to a quick charging station to charge. We set up cases that the charging thresholds are raised on Friday afternoon to prepare for EV use on a weekend.

Through the analysis targeting Aichi Prefecture, we obtained following findings. (1) As for the impact of the high power of quick chargers, the charging demand of a large number of EVs in the power system level is smoothed, but the same leveling effect is not expected when viewed locally, such as power distribution area level. Therefore, there is a possibility of overload of the power distribution facilities. (2) As for the impact of the change in charging behavior, even if the area mesh size is expanded, the smoothing effect of the charging demand cannot be expected. Therefore, it is especially necessary to take measures to avoid peak load at the power system level.

Conventional methods to schedule power generators maintenance aim to secure enough supply reserve margin to the power system when its power generators have to go under maintenance. However, the use of such methods in scenarios of large penetration of VRE, might be problematic. This is because in such scenarios conventional scheduling methods might inadvertently concentrate maintenance operations when residual demand is particularly low, creating situations in which there is insufficient supply-demand balancing capability and inertia to operate the power system properly. In this study, we present the development of a new method to schedule generator maintenance that ensure inertia and balancing capability constraints, and show its effectiveness.

Voltage rise is a significant challenge in the application of high-penetration solar photovoltaics (PV) to transmission systems. One explanation is a mismatch between PV power and load demand, which occurs regularly in Japan around April and May. Voltage violations occur when voltage levels exceed the allowed limits. To prevent voltage violations, many methods have been proposed, including volt-VAR control on inverters. The effect of employing a dynamic volt-VAR control rather than a static volt-VAR control in a high-penetration photovoltaic (PV) system is compared to that of using a static VAR compensator (SVC) in this study. The reactive power involvement of the PV inverter can be adjusted using dynamic volt-VAR control, which takes into consideration the inverter's available reactive power capacity. The amount of available capacity will influence how forceful the control is, which will be reflected in the droop gain. The controls are tested on the transmission system for a year to assess the number of uncompensated voltage events. The number of violations that the control cannot compensate for affects how much reactive power the SVC must provide.

The Power and Energy Society Annual Conference was held at Aichi Institute of Technology on September 4-6, 2023. Total number of papers was 303, and sessions were 43. An invited lecture, a panel discussion and two special lectures were also organized during the conference period. The number of participants reached 936. The conference was successfully completed with great contribution from all the participants. This report summarizes the conference.