Work

Revealing temporal and spatial variations in CO2 emission factor of electricity generation in Japan

Year: 2025

Type: article

Abstract: The electricity generation sector in many countries is undergoing drastic changes toward decarbonization. A major driver of this change is the rapid integration of renewable energy, the availability of which varies temporally and spatially. To evaluate how such variations affect CO 2 emissions from electricity generation, this study measured the average emission factor across 10 different electricity service areas in Japan . Using hourly generation data spanning seven years from each area, our study revealed substantial temporal and spatial variations in the emission factor. Specifically, the results show (1) significant intraday variation with smaller values during daytime hours, (2) yearly variation with decreasing values over time, and (3) substantial spatial variation in both temporal variation and magnitude. We also used real consumption data of heat pump water heaters to simulate the extent to which CO 2 emissions can be mitigated by shifting their operation schedules from midnight to daytime, finding that households can reduce CO 2 emissions by 158 kg annually on average.

Source: Energy

DOI: 10.1016/j.energy.2025.136237

Authors: Hideki Shimada, Tomonori Honda, Yuya Imamura, Ruth Anne Gonocruz, Akito Ozawa

Institutions: National Institute of Advanced Industrial Science and Technology, Kyoto University

Language: English

Topic: Integrated Energy Systems Optimization

Subfield: Electrical and Electronic Engineering

Field: Engineering

Domain: Physical Sciences

SDGs: Climate action, Affordable and clean energy

Open Access status: hybrid

Estimated APC paid: $4,260