Model development for estimation of CO₂ emission from household sector in Japan based on the diffusion of residential photovoltaic system and electric vehicles

Abstract

 The greenhouse gas (GHG) emission reduction targets in Japan are 26% reduction by FY 2030 compared to the level in FY 2013, and 80% reduction by 2050. It is required to reduce CO₂ emission drastically from energy consumption of households in order to achieve the targets. On the other hand, diffusion of new energy technologies such as residential photovoltaic (PV) systems and battery electric vehicles (BEV) have a great potential to change energy consumption and contribute to CO₂ emission reduction in household sector.

 Many previous studies on Japan’s mid- and long-term CO₂ emission from energy consumption analyzed the roles of residen-tial PV system or BEV outside of residential sector, and the impacts of such technologies on households’ energy consumption are not taken in account. In this study, a new device-selection model is constructed in order to assess the change of whole energy consumption caused by PV system and BEV in household. In addition, by the difference of household attibution such as house-holds living in detached house or apartment house, CO₂ emission from household is estimated, and feasibility of mid- and long-term CO₂ emission reduction targets is assessed.

 The results of model analysis indicate that it is necessary to decrease the CO₂ emission factor of grid electricity in order to achieve the 2050 target, and it is also required to promote electrification by decreasing city gas, kerosene and gasoline consumption. Residential PV system can increase the electrification rate of households and contribute to CO₂ emission reduction. BEV also have great potential to reduce CO₂ emission of households living in detached house with residential PV system at the same level of that in apartment house.This study concludes that PV and BEV play important roles to reduce CO₂ emission in household.