The Carbon Emission Assessment of a Building with Different Prefabrication Rates in the Construction Stage

Optimal carbon emission reduction path of the building sector: Evidence from China

To combat climate change, China's building sector, responsible for almost 50 % of national emissions, must undergo a drastic decarbonization transformation. This paper charts the optimal path to achieve this goal, leveraging a combined framework of the Low Emissions Analysis Platform (LEAP) and System Dynamics (SD) for scenario-based forecasting of energy consumption and emissions in 2021-2060. A linear programming model is further developed to identify the lowest-cost combination of 26 building green technologies that align with China's carbon peaking and carbon neutrality targets. Results show that in a business-as-usual scenario, building carbon emissions will peak at 6393 million tons of CO2 in 2041, missing the 2030 carbon peaking target. Key drivers of this shortfall include the high energy intensity for "Transport, Storage and Post" and the large carbon emission factors for "Wholesale, Retail Trades, Hotels, and Catering Services" and "Residential" sectors. Under various technology application scenarios assuming uniform penetration rates, the 2030 carbon peak target appears attainable, though at a considerably high cost. Finally, under optimal technology combinations, building carbon emissions are forecasted to peak in 2030 at 5139 million tons of CO2, a mere 4.4 % increase from 2020. The cost of this optimized combination is projected to represent only 1.5 % of the total GDP in 2060. This scenario also leads to a significantly weaker correlation between energy consumption and carbon emissions in the building sector around 2036, nearly 17 years ahead of the business-as-usual trajectory.

Building carbon peak scenario prediction in China using system dynamics model

As the issue of global climate change caused by carbon emissions is of great concern, China has proposed achieving its achieve carbon peak goal by 2030. Building carbon emissions account for approximately 50% of China's total carbon emissions. It is crucial to study the time and values of building carbon peaks. In this paper, based on a system dynamics model, logarithmic mean Divisia index model and Monte Carlo simulation, we predict the building carbon peak in China. The following conclusions are obtained: 1) in the baseline scenario, China's building carbon emissions will peak at 5,427 million tons in 2027. In the high-speed development scenario, China's building carbon emissions will peak at 6,298 million tons in 2032. In the coordinated development scenario, the green development scenario, the low-carbon development scenario, and the low-speed development scenario, the peak occurs in 2030 at 5,972 million tons, 5,991 million tons, 5,657 million tons, and 6,329 million tons, respectively. 2) According to the comprehensive simulation, China's building carbon emissions will reach the peak in 2030, with an 80% probability of reaching 5,729-6,171 million tons.

Evolutionary Analysis of Prefabrication Implementation in Construction Projects under Low-Carbon Policies

In the context of carbon peak and carbon neutral policies, low-carbon construction has been the focus of most countries worldwide. As one of the most effective ways to achieve green construction, many countries have launched low-carbon policies to promote the development of prefabrication. However, the effectiveness and influencing factors of low-carbon policies on prefabrication need to be further verified under the dynamic game between the government and the construction enterprise. Therefore, this study considered subsidy and carbon tax policies and developed an evolutionary game model to promote the development of the prefabricated construction market. The evolutionary stable strategy of the government and construction enterprise under different scenarios was obtained. Subsequently, a numerical analysis was conducted to further investigate the impact of the key factors on the stable strategy. The results showed that an appropriate hybrid policy of subsidies and taxes could positively promote the prefabrication implementation of the construction enterprise. The government should adopt an appropriate policy intensity according to the maturity of the market. This study can provide effective guidance and practical enlightenment for the government to achieve low-carbon, green, and sustainable construction.

SEM-Based Analysis of Carbon Emission Reduction Pathway Study during the Materialization Stage of Prefabricated Buildings: Evidence from Shenyang and Guiyang, China

In recent years, in the process of promoting prefabricated buildings, problems such as waste of resources and energy have been present, which have seriously hindered the realization of carbon emission reduction benefits of prefabricated buildings. Especially during the materialization stage of prefabricated buildings which involves the most engineering activities and the most extensive sources of carbon emissions, it is urgent to further meet the low-carbon development of the construction industry. This study takes the 4 substages of design and development, component production, transportation, and installation during the materialization stage as the point of penetration and identifies the carbon reduction impact pathways based on the 3E (Environment-Economy-Energy) system theory in 5 dimensions: government policy, management mode, technology level, economy input, and energy structure. The data are collected through the questionnaire survey, and structural equation modeling (SEM) is utilized to examine the hypothesis and impact dimensions of the study. The results confirm that the management mode has the strongest effects on carbon emission reduction, followed by government policy, economy input, and technology level, and the energy structure has the weakest effects. This study presents the key carbon reduction pathways during the materialization stage of prefabricated buildings and provides recommendations for different participants to optimize policy guidance, strengthen management supervision, accelerate technology research and development, increase economy input, and optimize energy structure, with a view to achieving low-carbon governance capacity, management mode, technology system, capital, and energy utilization, and also enriches the theory in the field of prefabricated buildings carbon emission reduction, which can better achieve low-carbon development of prefabricated buildings.

Safety Risk Assessment of Prefabricated Buildings Hoisting Construction: Based on IHFACS-ISAM-BN

Prefabricated buildings that are more environmentally friendly have been vigorously promoted by the Chinese government because of the reduced waste and carbon emissions during the construction process. Most of the construction processes of prefabricated buildings are completed in the prefabricated component factory, but the safety risks during the hoisting process cannot be ignored. In this paper, the initial framework of a Bayesian Network (BN) is obtained from the combination of the improved Human Factors Analysis and Classification System Model (HFACS) and BN. The improved similarity aggregation method (SAM) is used to calculate the prior probability of BN, which can better summarize and deal with the fuzzy judgment of experts on risk accidents. The improved SAM can consider both the weight of experts and the relative consistency of their opinions, which is of great significance for improving the reliability of BN inputted data. This paper uses the construction project in Sanya, Hainan Province, to verify the validity of the model. The results show that the calculation results of the model are basically consistent with the actual situation. The safety risk of this project is relatively low, and the premise of unsafe behaviors and unsafe supervision are the key risk factors of the project. In addition to maintaining good construction conditions and workers’ healthy states, it is also necessary to carefully check the performance of tower cranes and equipment such as spreaders. During the operation process of the tower crane, workers should avoid walking or staying within the hoisting range.