著者

西尾 健一郎 向井 登志広

出版者

日本建築学会

雑誌

日本建築学会環境系論文集 (ISSN:13480685)

巻号頁・発行日

vol.81, no.729, pp.1025-1034, 2016 (Released:2016-11-30)

参考文献数

22

被引用文献数

1

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Time-of-use (TOU) rates are one of the electricity rates designed to encourage consumers to shift their electricity usage from peak hours when the grid electricity demand increases to off-peak hours. Compared with other demand response rates such as critical peak pricing, TOU rates are considered to be more modest and acceptable. To evaluate the impact of TOU rates in Japan, the Japanese government conducted a pilot study that analyzed the amount of electricity saved during peak hours in the summer by using metering data; however, little is known about the impact of TOU rates on the awareness and behaviors of electricity consumers. In order to analyze actual behavior changes, we conducted a web-based questionnaire survey of 4,000 households, including those who use and do not use TOU-type tariffs. In practice, there is a non-negligible difference in characteristics such as building and household attributes between TOU users and non-TOU users because of the nature of TOU, for example, TOU users live in relatively larger and newer houses, and the number of households is more than that of non-TOU users. Therefore, we use a statistical method, called propensity score inverse probability weighting (IPW) estimation. This method is categorized as a type of quasi-experiment, which is used when it is difficult to conduct randomized controlled trials. An IPW estimation creates a quasi-homogeneity of covariates, namely, types and ownerships of houses, construction years, floor spaces, satisfaction of insulation property, availability of space-heating by air-conditioners, number of households, and regions. The result shows that more than 60% of the households using TOU are aware of some kind of changes triggered by the differences in the electricity unit price between daytime and nighttime. Typical changes are shift of usage hours from daytime to nighttime, and end use with high awareness rate as a whole with regard to air-conditioners, dishwashers, rice cookers, washing machines, etc. In particular, almost half of the households with dishwashers and washing machines with drying functions are conscious of shift in usage hours. Moreover, a comparison of bihourly weekday usage rates reveals the statistically significant differences in the usage patterns of air-conditioners, clothes dryers, dishwashers, rice cookers, and home bakery machines. These changes are positively accepted by TOU users, as compared with the impressions gained from non-TOU users. Meanwhile, there are appliances whose usage is less likely to be shifted, such as TV. The possibility of behavior changes varies depending on characteristics of the way of use and the functionality, such as timer control. Moreover, the benefits and limitations of the method are discussed. Although it is difficult to elaborate the amount of electricity saved from the data used in this study, a properly managed statistical tool could provide alternative opportunities to understand the mechanism of behavioral changes by using data obtained from the real world.