Evaluating decarbonization scenarios and energy management requirement for the residential sector in Japan through bottom-up simulations of energy end-use demand in 2050

Abstract

Decarbonization scenarios for achieving net zero greenhouse gas emissions in the Japanese residential sector by 2050 were examined using a bottom-up simulation model of energy end-use demand. The examined scenarios involve the dissemination of currently available technology, including highly insulated houses, high-efficiency equipment, high-efficiency appliances, electrification, and building-integrated photovoltaics (PV) in detached houses. The results show that decarbonization can be mostly achieved by the studied scenarios, especially through the dissemination of highly insulated buildings and high-efficiency water heaters as well as the installation of PV for all detached houses. This scenario reduced the total primary energy demand by 61% in 2013. A land-use strategy for increased detached houses is preferable for increasing PV capacity. For the scenario that achieves net zero energy, the predicted heat load intensity and electricity consumption per capita are almost the same as those of the Low Energy Demand (LED) scenario. Increased dependence on PV will create an imbalance in the relationship between electricity supply and demand, and 26% of the residential energy demand would rely on non-battery energy storage, such as pumped hydropower and hydrogen, owing to the seasonal time gap between residual and deficit electricity.