Abstract: To address the increasing challenge of resource utilization of urban solid waste, a novel low-carbon supercritical water gasification (SCWG) system coupled with solid oxide fuel cell (SOFC) for combined heat and power (CHP) generation was proposed, which used coal and solid waste as co-fuels. The system employed chemical looping to reform the outlet syngas and capture carbon, while solar energy was introduced as the input to heat the gasification preheater and the calcium carbonate calciner. To further enhance waste heat recovery and carbon capture efficiency, the system was optimized by replacing the gasification system cooler with an organic Rankine cycle (ORC) for partial energy recovery, and by adopting anode fuel recirculation to improve CH₄ reforming conversion. Based on these improvements, energy and exergy analyses were conducted to explore the effects of key parameters on the system performance. Results show that the improved system outperforms the original design in all performance metrics. The introduction of the ORC and fuel recirculation significantly increases power output and carbon capture. The improved system achieves high energy efficiency and carbon capture rate under design operating conditions: energy efficiency of 64.97%, power generation efficiency of 52.24%, exergy efficiency of 51.34%, and carbon capture rate of 94.34%, which are improvements of 2.03, 3.10, 3.01, and 18.15 percentage points, respectively. Increasing the gasification temperature and system water input or reducing gasification pressure all enhance hydrogen production in the gasification system. A lower coal-to-solid waste ratio improves the gasification conversion of the fuel. Higher SOFC operating temperature and pressure also improve system energy efficiency, with an optimal temperature range of 850-990 ℃. When the fuel recirculation ratio exceeds 0.75, near-zero CO₂ emissions can be achieved.