A net-zero polygeneration system for power, hydrogen and ammonia: energy, exergy and exergoeconomic (3E) analyses

• A polygeneration system produces power, hydrogen, and ammonia. • The system achieves an overall efficiency of 63 %. • Exergoeconomic analysis identifies the electrolyzer and combustor for improvements. • Power costs $32.06/MWh, hydrogen $2.15/kg, and ammonia $364/ton. • The total product unit cost is $15.9 per GJ. This study proposes a novel polygeneration system that simultaneously produces power, hydrogen, and ammonia with net-zero CO 2 emissions. It integrates the oxy-combustion Allam cycle for power, an alkaline electrolyzer for hydrogen, and the Haber-Bosch method for ammonia synthesis. The system leverages byproduct reutilization and heat integration to enhance efficiency and reduce energy consumption. Heat integration is a critical aspect of this study, improving overall system efficiency. The research further provides valuable insights through 3E analyses, energy, exergy, and exergoeconomic assessments, along with a parametric investigation to evaluate the impact of key variables on both subsystems and system performance. The main results indicate that through integration, the Allam cycle efficiency increases from 54.2 % to 66.4 %, with the electrolyzer reaching 70.3 % efficiency and ammonia synthesis 79.4 %. System output contributes 38 % (468 MW e ) for power, 33 % (434.4 MW e ) for ammonia, and 27 % (329.86 MW e ) for hydrogen. Exergy losses are highest in hydrogen and power production (47% each), with ammonia synthesis at 6 %. Exergoeconomic indicators identify the electrolyzer and combustor as key units requiring improvement to enhance the system’s economic performance. Power production costs $32.06/MWh, hydrogen costs $2.15/kg, and ammonia costs $364/ton, with a total product unit cost of $15.9 per GJ and an overall system efficiency of 63 %. A sensitivity analysis reveals that system efficiency is most influenced by turbine outlet pressure and electrolyzer recirculation molar flow, while ammonia synthesis temperature, combustor outlet pressure, and ammonia synthesis pressure have comparatively smaller effects.