Residential energy consumption by Japan’s super-aging society: visioning a more sustainable future up to 2040

Japan is a leading exemplar of rapidly aging countries, holding very low fertility rate. Under such circumstances, the present paper examines two important aspects of residential energy consumption patterns of Japan up to the year 2040: (i) presenting two future scenarios of residential energy consumption and (ii) reexamining the effectiveness of traditional strategy to reduce energy consumption mainly through energy efficiency improvement. Before presenting the two main topics of the paper, three important factors are discussed: (i) the population aging effect; (ii) the generation gap in energy use patterns; and (iii) the decline in family size. These factors influence the relationship between the aging population and residential energy consumption. Then, a brief explanation is given for survey data sources, six household types in 11 regions of Japan, and four types of energy carriers. The first scenario assumes that residential energy consumption pattern of each household type remains unchanged from the current situation and that the population projection holds true. The total residential energy consumption will decrease by only 6% between 2020 and 2040. Yet, per capita residential energy consumption will increase despite the fact that the population size will decrease by 10.6%. The second scenario assumes that slightly higher energy efficiency improvements than in the past 15 years will continue to reduce energy consumption from 2020 to 2040. The simulation result of this optimistic scenario also suggests that conventional energy conservation strategies alone are far from sufficient to reduce residential energy consumption per capita. Thus, an alternative strategy to overcome the spell of Jevons’ paradox is urgently required. Frugality combined with lifestyle and behavior change should be seriously attempted to achieve sustainable future for societies including aging countries like Japan.