Energy efficiency measures towards decarbonizing Japanese residential sector: Techniques, application evidence and future perspectives

Improving energy efficiency presents great potential to reduce energy consumption and carbon emission of building sector. This work summarizes existing technological innovations, energy management efforts and demonstration effect for decentralized and decarbonized energy transition in Japanese residential sector. Additionally, the study provides a comprehensive understanding of how various energy-efficient technologies and energy management strategies perform using behind-meter data. Measurement analysis shows that electrifying hot water demand would significantly reshape electricity load pattern, overall energy efficiency of cogeneration system highly depends on patterns of household energy demand. Going beyond generation efficiency of on-site energy generators, practical experiences emphasize roles of demand flexibility in improving alignment between distributed energy generation and demand. Demand-side energy management plays crucial roles in fully harnessing benefits of energy efficiency measures in representative residential energy systems. Survey results of demonstration projects verify effectiveness of implementing energy efficiency measures in cost and carbon emission reductions. As penetration of distributed energy resources and building electrification continues to increase, the study identifies impacts of integrating energy resources on public grid, potential grid-interactive interactions. From a holistic system perspective, findings highlight importance of demand-side solutions in exploiting energy flexibility and provide implications for effective decision-making toward energy use efficiency.