Evaluating Japan’s national greenhouse gas reduction policy using a bottom-up residential end-use energy simulation model

Abstract

The national policy in Japan for reducing greenhouse gas (GHG) emissions in the residential sector by 2030 is evaluated using a bottom-up-type simulation model called the Total Residential End-use Energy Simulation (TREES) model. According to the Japanese Plan for Global Warming Countermeasures (PGWC), the target GHG reduction in the residential sector is expected to be realized through the aggregated effect of various mitigation measures. In evaluating the impact of these measures, the following three factors must be considered: occupant behavior, differences in the effect among households, and secondary impacts. In this paper, to discuss the required specifications for supporting the policies related to GHG reduction, these factors are examined via the TREES model, considering the differences in the energy use among households due to occupant behavior, appliance/equipment ownership, and building energy efficiency. The simulation results of the end-use energy in the Japanese residential sector in 2013 show good agreement with available statistical values. The results of the TREES model applied to evaluate the proposed countermeasures suggest that 1) The Japanese government may be overestimating the effect of high-efficiency lighting installations, 2) The reduction in the total energy use varies by a factor of two depending on the combination of high-efficiency water heaters and household characteristics, 3) The relationship between the types of water heater and space heating system influences the effect of high-efficiency water heater installations, and 4) Energy demand reduction affects the electricity load curve and CO2 emission intensity of the electricity grid.