Life cycle analysis and multi-objective optimization of CCUS-integrated methanol reforming PEMFC-CCHP systems

Distributed methanol steam reforming (MSR)-proton exchange membrane fuel cell (PEMFC) systems have attracted attention due to their high efficiency, flexibility, and cost-effectiveness. Coupling these systems with combined cooling, heating, and power (CCHP) configurations further enhances energy utilization. However, their strong reliance on fossil fuels leads to substantial carbon emissions. Although integrating carbon capture, utilization, and storage (CCUS) mitigates operational emissions, it introduces additional energy penalties, economic costs, and complexity, while its full life cycle environmental benefits remain insufficiently understood. Moreover, conventional single-objective optimization is inadequate to simultaneously balance energy, economic, and environmental performance. To address these challenges, this study proposes a novel distributed MSR-PEMFC-CCHP system integrated with CCUS and develops a comprehensive evaluation framework combining life cycle assessment (LCA) and multi-objective optimization. Three configurations—CCHP-C (without carbon treatment), CCHP-S (with CCS), and CCHP-M (with CCUS)—are systematically analyzed to quantify full life cycle environmental impacts and identify optimal trade-offs. Results show the operation stage dominates life cycle emissions, contributing over 80 % in all configurations. Under the adopted inventory assumptions and system boundary, CCHP-M has the lowest total pollutant emissions and global warming potential, whereas CCHP-C has lower acidification and respiratory effect potentials. For CCHP-M, the selected compromise solution, Point D, achieves an energy efficiency of 85.61 % and an LCOE of 0.2463 $/kWh. Compared with the energy-optimal solution, Point K, Point D reduces the LCOE by 2.84 % and lowers life-cycle CO 2 -equivalent emissions by 2.816 t, or 4.14 %, to 65.153 t, while decreasing energy efficiency by 1.79 %. These results identify the environmental trade-offs among the three carbon-management configurations and the operating compromise within CCHP-M.