Osaka Gas Co., Ltd. (大阪ガス株式会社 or 大阪瓦斯株式会社, Ōsaka Gasu Kabushiki-gaisha), commonly written as 大阪ガス, is a Japanese gas company based in Osaka, Japan. It supplies gas to the Kansai region, especially the Keihanshin area when an advert of 1986 used the Mr. Men series by Roger Hargreaves.Osaka Gas is also engaged in upstream, midstream and downstream energy projects throughout the world, including LNG terminals, pipelines and independent power projects, particularly in Southeast Asia, Australia and North America.
In response to the global imperative of achieving carbon neutrality, increasing attention is being directed toward procuring Frequency Containment Reserve (FCR) not from conventional thermal power plants, but via Virtual Power Plants (VPPs) that aggregate thousands of distributed energy resources (DERs) such as photovoltaics (PV), battery energy storage systems, and fuel cells. These VPPs, coordinated by aggregators, harness the controllable surplus capacity of DERs—excluding on-site consumption—to participate in day-ahead FCR markets. For effective market participation, aggregators must schedule FCR provision by optimizing expected market revenue while accounting for PV generation, electricity consumption, and the dispatchable capacity of each prosumer. On the day of operation, the VPP is required to deliver dynamic power responses to grid frequency deviations, which arise from imbalances between supply and demand. In systems with high penetration of variable renewable energy sources, grid frequency exhibits pronounced volatility and uncertainty. Consequently, relying on a single deterministic frequency forecast may lead to scheduling errors, resulting in inadequate controllable capacity during real-time operation. To address this issue, we propose a scenario-based FCR scheduling framework that incorporates probabilistic frequency forecasting using Natural Gradient Boosting (NGBoost) and a copula-based model. NGBoost provides probabilistic forecasts that capture predictive uncertainty, while copulas enable the modeling of complex temporal dependencies in frequency fluctuations. By integrating these probabilistic scenarios into the scheduling optimization as constraints, the proposed method enhances the reliability of VPP-based FCR provision. Simulation results based on real data from 2000 prosumers confirm the validity of the proposed approach.
Buried gas pipeline is subjected to a large axial load due to earthquake-induced ground flow. The deformability of the pipeline depends on the strength of the girth weld joint. Since the heat-affected zone (HAZ) of tempered steels is locally softened due to the heat input of girth welding, the strength of the girth weld may be affected by softened HAZ. In addition, as for gas pipeline, the effect of internal pressure on the strength of the girth weld joint should be considered. Therefore, this paper proposes a tensile strength evaluation formula for girth weld joint with softened HAZ under internal pressure. The formula is developed by modifying the existing tensile strength evaluation formula of the wide plate of weld joint with softened HAZ, considering the effect of internal pressure using the elastoplastic finite element analysis. In this modification, the effect of both internal pressures on the apparent tensile strength of pipe material and the shrinkage behaviour of pipe material are focused on. Furthermore, the validity of the modified formula is demonstrated by conducting full-scale pipe tension tests.
Solid Oxide Fuel Cells (SOFCs) are highly efficient energy conversion devices that produce electricity and heat through an electrochemical process. The widespread adoption of SOFCs is essential for achieving a sustainable, low-carbon society. Since 2012, OSAKA GAS has commercialized the ENE-FARM type S (EF) as a residential SOFCs combined heat and power (CHP) system. The widespread adoption of the EF requires addressing key challenges such as high efficiency, durability, low cost, and downsizing. EF was remodeled in 2016 and 2020 to address these issues. Metal-supported SOFCs (MSC) use a metal substrate that is low-cost and durable as a support, allowing for cost reduction and downsizing. However, there are concerns about the durability of the ferritic stainless-steel component at high temperatures. For this reason, MSC is generally positioned for low-temperature operation. Conversely, SOFCs constructed from ceramics are known to perform optimally at higher temperatures. Therefore, we have been working on the development of MSC that can be operated in the same temperature range as their anode-supported counterparts. The concepts of the MSC are to achieve both high output and high durability. In this study, the durability of MSC was evaluated at high temperature. The MSC was fabricated with ceramic electrodes and an electrolyte on a ferritic stainless-steel support with through-holes at low temperature. The configuration included a metallic interconnector, which was coated with ferritic stainless-steel welded around the cell, referred to as a Single Cell Unit (SCU). The perimeter welding between the cell and the metal interconnector served as a seal on the fuel side, ensuring gas tightness. The operating conditions involved a current density of 0.336 A/cm² and a mixed gas of H₂, N₂, and H₂O with Fuel Utilization (Uf) 80% supplied as fuel gas, along with air at Air Utilization (Ua) 30%. Durability evaluations were conducted in the temperature range of 700 to 850°C.Figure 1 shows the result of the durability testing at 700°C. Over the operation time of 10000 hours, the degradation of MSC-SCU was minimal. During the durability testing, the open circuit voltage (OCV) and internal resistance (IR), as well as electrode overvoltage (η), were measured. IR and η were measured using current interruption. The OCV of MSC-SCU showed almost no change during the 10000 hours durability testing. The small voltage degradation was attributed to increases in IR and η. It was assumed that potential causes for the increase in IR include reduced ionic conductivity due to phase transitions in the electrolyte, the formation of high-resistance layers, and increased oxide layer thickness. Factors contributing to the increase in η were related to sintering or poisoning of the fuel or air electrodes, leading to a decrease in the reaction area or reduced gas diffusion capability. In addition to separating IR and η, the influence on the fuel electrode side was evaluated by varying Uf. Uf dependence of the cell voltage changed little before and after durability testing. This result suggested that the factors contributing to the increase in η were likely located on the air electrode side rather than the fuel electrode side. The MSC is being developed for achieving compactness, lightweight design, and low cost, while striving to balance high efficiency and durability. In this study, the durability of the MSC under conditions of 700°C was evaluated. There was no rapid or significant degradation even after 10000 hours of operation at 700°C. To further enhance durability, we will continue to focus on improvements and long-term durability testing, with the goal of integrating these cells into the EF. Additionally, we are also exploring the technological application of SOEC to realize a decarbonized society. Figure 1
