Mitigating building carbon emissions in high-density cities considering energy sufficiency

Countries worldwide are heading toward carbon neutrality. High-density cities, viewed as a sustainable future, exhibit unique emission patterns dominated by buildings. Meanwhile, as an important indicator of well-being, energy sufficiency should be prioritized during decarbonization. This research employed Hong Kong as a case, utilized multi-source open data to incorporate technological and socio-economic factors, and developed a modeling framework for projecting long-term carbon emissions under various scenarios and the sufficient-energy case, and decomposing the yearly contributions from both electricity demand and supply sides by time. Results reveal the essentiality of radical policies for carbon neutrality, necessitating simultaneous decarbonization of the electricity demand and supply sides. Limited space for renewables in high-density cities makes demand-side decarbonization even more vital, in which the electrified appliances display significant potential. Among building types, public facilities, multi-functional commercial buildings, and private housing offer substantial decarbonization potential. This study pioneeringly incorporates energy sufficiency into the context of carbon neutrality and defines the upper and lower boundaries for energy sufficiency. It proposes targeted policy recommendations to ensure decent living standards while reducing emissions and demonstrates how decarbonization can enhance energy equality across building types.