Factorial socio-economic and environmental equilibrium analysis of large-scale hydropower toward sustainable development: Evidence from the Xiangjiaba hydropower project, China

Large-scale hydropower projects (LHPs) provide multiple operational benefits, and the resulting direct effects can propagate through input-output linkages and generate indirect socio-economic and environmental (SEE) effects. However, such indirect effects and the interactions among critical determinants have not been systematically assessed. To address this gap, this study develops a Factorial SEE Equilibrium Analysis (FSEA) model that integrates a disaggregated computable general equilibrium framework with multi-level factorial analysis to quantify function-specific indirect effects, focusing on economy-wide economic outcomes and supply-chain embodied carbon emissions, and to examine key impact factors and their interactions. The model is applied to the Xiangjiaba Hydropower Project (XJB) in the Yangtze River Economic Belt (YREB), China. Results indicate that XJB contributes 18.09 billion yuan to YREB's GDP, with the indirect gains accruing mainly to public fiscal accounts under the model's investment-driven closure. The six operational functions of XJB exhibit distinct patterns in terms of economic contributions and carbon emissions. GDP gains are concentrated in the hydropower generation and water conservancy management functions. With respect to carbon emissions, the hydropower generation function delivers net emission reductions through clean electricity substitution, whereas the water conservancy management function accounts for the largest share of supply-chain embodied emissions. The factorial analysis identifies labor demand as the dominant driver of GDP variation, with a pronounced interaction between labor demand and capital demand. These findings provide function-level quantitative evidence for multipurpose LHPs and can help inform differentiated policy making toward sustainable energy development.