Low carbon financial evaluation system and application of construction engineering based on AHP-Topsis method

Abstract This study addresses the challenge of integrating environmental benefits into traditional financial evaluation systems for construction engineering under low-carbon transition. A dynamic low-carbon financial evaluation model is constructed using the AHP-Topsis method, overcoming limitations of existing single-dimensional approaches, subjective weight allocation, and insufficient dynamic adjustment. The model reconstructs a three-level indicator system (economic, environmental, technological) and employs the Critic-entropy weight combination method for objective weighting, incorporating time-series and policy factors for dynamic optimization. An empirical analysis of data from 263 enterprises reveals that green infrastructure firms exhibit a comprehensive closeness degree (Ci) of 0.85 for low-carbon finance, significantly higher than industrial plants (0.46). Their carbon emission intensity is 28% lower, with green technology investment intensity 4.2 times higher. Regional comparisons reveal eastern enterprises have 50% lower emission intensity and 1.5 times higher green investment returns than western counterparts, attributed to policy synergies. Model validation demonstrates the combined weighting method increases the carbon emission intensity weight to 24.4% with a stability coefficient of 2.5%, improving calculation efficiency by 57%. The dynamic closeness degree rose from 0.48 in 2019 to 0.68 in 2024. The system offers enterprises a decision tool: a 10% increase in green building material usage shortens the payback period by 1.2 years. For governments, it supports differentiated carbon tax policies (e.g., eastern carbon price elasticity of 0.0021), facilitating precise low-carbon transformation in the industry.