Improvement of carbon peaking path in the construction sector in medium-sized cities: A case study of Zhangzhou city, China

Abstract

Carbon reduction in the urban and rural construction sector plays a strategic role in helping China achieve its carbon peak target by 2030. Using Zhangzhou as a case study, this research developed and compared top-down and bottom-up carbon emission prediction models based on field surveys and literature, revealing emission characteristics of medium-sized cities. Seven carbon reduction measures were integrated in the models: conserving energy in new buildings, retrofitting existing buildings, using renewable energy (RE) in urban areas, using RE in rural areas, electrifying energy use, using green lighting and creating greenfield carbon sinks. To quantify the measures’ contributions, a business-as-usual (BAU) scenario and two carbon reduction scenarios—stable decarbonisation and rapid decarbonisation—were established using scenario analysis. The results showed that (1) in the BAU scenario, the predictions of the two models differed by less than ±10 %, with the bottom-up method projecting a carbon peak in 2038 at 4.672 million tonnes of CO₂; (2) the carbon peak could be advanced to 2030 and 2026 under stable and rapid decarbonisation scenarios, with carbon emissions of 4.103 and 3.937 million tonnes of CO₂, respectively; and (3) RE use and energy conservation in new buildings are key drivers of carbon reduction, and the contributions can reach 18.15 % and 32.26 %, respectively. This study verified the accuracy of carbon emission forecasts by comparing two prediction methods, providing a basis for the formulation of emission reduction measures. Additionally, it considered the coordinated optimisation of infrastructure and addressed the research gap in medium-sized cities, offering references for low-carbon development strategies in similar regions.