Decarbonizing power generation through Iron-based fuel cycles: A thermodynamic and thermo-economic analysis

Abstract

A novel zero‑carbon power generation system for a 300 MW plant is proposed, utilizing iron as a chemical energy carrier to integrate renewable energy. In the proposed system, iron combustion drives the steam Rankine cycle for electricity generation, and the produced iron oxide is reduced by hydrogen from an alkaline electrolyzer powered by renewable energy, completing the cycle. Relative to a conventional 300 MW coal-fired plant based on 5E (Energy, exergy, environmental, economic and exergoeconomic) analysis, the proposed system demonstrates a 0.72 % improvement in energy efficiency and a 12.35 % increase in exergy efficiency. The power conversion efficiency of the proposed system is 10.64 % higher than that of the methanol-based hydrogen production system. The life cycle assessment has validated the environmental friendliness of the system during its operation process. The cost of electricity production is reduced from 94.57 $/MWh to 60.01 $/MWh, with minimal influence from iron costs due to low cycle losses. Economic analysis indicates that the photovoltaic system, alkaline electrolyzer, and steam Rankine cycle contribute to 98.31 % of total economic losses. The proposed system facilitates long-distance, efficient renewable energy utilization and zero‑carbon power generation, providing a feasible framework for energy decarbonization and cross-regional renewable energy integration.