Research On Incremental Cost And Benefit Evaluation Of Prefabricated Buildings Based On Carbon Emission Reduction

In the process of industrial modernization,GHG(Greenhouse Gas,GHG)emissions have been increasing because of the massive energy consumption,leading to increasingly serious environmental pollution.As one from the three major energy-consuming industries,the effective way to achieve the goal of "double carbon" is to transform,upgrade and sustain the healthy development of the construction industry.With the advantages of high productivity,low energy consumption and environmental protection,assembled buildings are the key to industrialization and greening of the construction industry.However,the promotion of assembled buildings is hindered by high construction costs and the development is slow overall.With the above issues in mind,this paper is aimed at exploring the use of economic instruments to quantify the emission reduction effects of assembled buildings,so as to discuss and analyze the incremental costs and benefits generated by assembled buildings in a more indepth and comprehensive manner,and to provide a reference basis for developers’ investment decisions and policy formulation of subsidy policies.With the relevant theories,this study first analyzes the sources and components of carbon emissions in the six phases of the whole life cycle of assembled buildings,and set up a carbon emission accounting model for the characteristics of each phase.It is followed by a comparison with cast-in-place buildings to make an analysis of the components of incremental costs and benefits over the whole life cycle of an assembled building,and the accounting method is provided for each component.In combination with the previous study,the system dynamics theory is used to analyze qualitatively the cause-effect relationship among the factors,and on this basis,the causal loop diagram is drawn,and then the various variables in the system are determined and the stock flow diagram and system dynamics equations are constructed to complete the system model of incremental costs and benefits of assembled buildings.At last,the feasibility and rationality of the established estimation model is verified by combining with the example of assembly building projects,and the incremental costs and benefits are evaluated based on the results of model runs and scenario simulations,with the following main conclusions:(1)The carbon emission system of assembled buildings was established by adopting the carbon emission factor method.Through the identification and quantification of various carbon emission sources in the six phases of the whole life cycle of assembled buildings,it was found that assembled buildings produce the most carbon emissions in the production phase and the most obvious carbon emission reduction in the operation phase.(2)The manufacturing stage,transportation stage and installation stage of components are the main stages of incremental costs of the assembled building,among which the production cost of prefabricated parts accounts for the largest share of the total incremental costs,followed by the incremental costs generated in the installation stage.(3)The environmental benefits brought by prefabricated buildings are significant,and the incremental benefits of prefabricated buildings are greatly reduced without considering environmental benefits.(4)Large-scale production can reduce incremental costs due to the adoption of assembled buildings,while expanding the scale of assemblies and government subsidies are effective in reducing single-party incremental costs.(5)Subsidies for the production and installation phases can effectively reduce the incremental cost of assembled buildings.