In the context of a feed-in tariff (FIT) scheme, this study examines the economic implications of solar power curtailment in Kyushu, Japan, a region with a high penetration of solar photovoltaic power. By defining the potential market value of curtailed electricity, it analyzes how economic benefits and burdens are distributed among renewable producers, retailers, conventional generators, and consumers. Two utilization scenarios—daytime load creation and battery-based time shifting—are compared. The merit-order effect is minimal in the former scenario and is much less than battery cost in the latter scenario. These results indicate that under current institutional and cost conditions, benefits tend to concentrate among specific stakeholders, while consumer burdens persist. The policy implications include the introduction of separate metering and low-priced market mechanisms for curtailed electricity, as well as compensation schemes to ensure a fair allocation of benefits across stakeholders.

In recent years, there have been serious damage to photovoltaic array frames in the east Hokkaido region that appears to have been caused by frost heaving. Decreasing the load carrying capacity due to damage to columns is concerned in the long-term service. In this study, a loading experiment was conducted using full scale specimen to figure out the response of members when large frost heaving occurs. In this experiment, the same specimen used in outdoor frost heaving test was reused. Steel pipe pile under the column was removed to install hydraulic jack at the bottom of the column, and reaction foundation was constructed before the experiment. Results of study, it showed that torsional deformation occurred in the column as the jack-up amount increased. Also, increasing amount of jack-up, it caused concern about module-to-module interference. However, the preceding interference between girder beams did not cause catastrophic damage to the module.

For cost-effective and flexible multi-junction solar cells, the development of high-quality infrared-absorbing Ge layers on general insulating substrates is essential, yet has been hindered by small grain sizes and high defect densities in conventional polycrystalline films. In this study, we employed a solid-phase crystallization technique combined with subsequent grain-templated growth to control microstructure evolution. By suppressing interfacial nucleation, a large-grained seed layer was formed, enabling thick Ge growth while preserving the enlarged grain structure. The resulting Ge films exhibited significantly improved crystallinity, with large grain sizes and reduced acceptor defect density, leading to enhanced carrier transport. As a result, clear photoresponsivity was demonstrated in polycrystalline Ge layers on glass. Furthermore, this low-temperature process (< 500 °C) was extended to polyimide films, where Ge-related photoresponsivity up to 1.8 μm was observed, suggesting efficient infrared carrier generation and extraction. These results establish a viable route for realizing high-quality Ge thin films on low-cost and flexible substrates, providing a promising platform for next-generation multi-junction solar cells and infrared optoelectronic devices.

To determine the optimal equipment capacity for a school equipped with evacuation shelter functions from both economic and resilience perspectives, power generation and consumption simulations were conducted. Assuming normal and emergency load profiles based on the facility scale, the 20-year economic performance and the ability to supply emergency loads continuously for 72 hours were evaluated. The optimization was carried out with the aim of maximizing resilience while minimizing the total system cost. As a result, the economic optimal equipment capacity was 68 kW of PV and 0 kWh of BESS, while the resilience optimal equipment capacity was 19 kWh of BESS for a school (whole floor area: 5600 m², evacuation shelter (gym): 1000 m², shelter capacity: about 300 people). Integrating both aspects, the overall optimal equipment capacity was 68 kW of PV and 19 kWh of BESS. In addition, an approximate formula for estimating PV capacity and BESS capacity were derived.