Towards a low-carbon countryside: Lifecycle embedded carbon emission analysis and reduction recommendations for farmhouses in Ningbo

Currently, about 35% of China’s population still lives in rural areas. To further promote the achievement of the “30-60 carbon peak & carbon neutrality”” goals, it is particularly important to focus on the design and research of low-carbon construction or renovation of farmhouse. In the past, most energy-saving retrofit studies have concentrated on the energy-efficient design of buildings but have often neglected the embedded carbon emissions of buildings. This neglection can result in achieving reduced carbon emissions during the operation phase of the building, but it fails to assess and optimize the overall carbon emissions from a whole lifecycle perspective.

This study examines the embedded carbon emissions of 19 farmhouse designs in Ningbo, selected from the “Ningbo City Traditional and Modern Farmhouse Ultra-Low Energy Design Common Atlas,” compiled by the Housing and Urban-Rural Development Bureau of Ningbo City in collaboration with the University of Nottingham Ningbo China. Based on the carbon emission factors presented in the “Standard for Building Carbon Emission Calculation GB/T 51366-2019,” this study calculates the carbon emissions generated during the manufacturing and transportation processes of building materials for the target buildings. A Monte Carlo sensitivity analysis was employed to further analyze the impact of fluctuations in carbon emission factors on embedded carbon emissions, and recommendations were made to reduce the carbon emissions of such farmhouse. The study found that carbon emissions from exterior wall materials have the most significant impact on overall carbon emissions, followed by roof materials. In contrast, the effects of transportation distance and transportation carbon emission factors are relatively minor.

In practical terms, the study recommends prioritizing the use of heavy diesel trucks (30 tons or 46 tons) for transporting building materials in rural areas to reduce transportation carbon emissions. Furthermore, future farmhouse designs should promote the use of ultra-low energy building materials to achieve significant long-term reductions in carbon emissions. Policymakers should also optimize transportation networks and infrastructure to enhance the efficiency of heavy transportation vehicles and further reduce carbon emissions during transportation.