This study develops a framework to continuously monitor nationwide and regional electricity demand trends after removing weather effects. Using hourly data from April 2019 to March 2025, multiple linear regression models incorporating meteorological and calendar variables estimated “weather-adjusted demand” based on the 30-year climate average (1991-2020). Results show that national demand declined in FY2020 due to COVID-19 impacts, recovered in FY2021, and then declined again from FY2022 onward, with FY2023 and FY2024 both around 3.8% below FY2019 levels. This pattern was consistent with official demand projections and final energy consumption statistics. Regional analysis indicated smaller declines in Kyushu and Okinawa, while most other regions showed decreasing trends compared to FY2019. Regression analysis indicated that weather-adjusted demand was positively associated with the Index of Industrial Production and negatively associated with electricity prices, while a 2023-specific factor also contributed to demand reduction. This study demonstrates the utility of a weather-adjusted demand monitoring framework that enables multi-granular analysis (annual, monthly, hourly) across all supply areas. While the results enhance understanding of recent demand trends, further research and the combination of various insights are needed to fully elucidate the drivers of electricity demand changes.
Yamada et al. (Sat,) studied this question.