Comprehensive evaluation on a heat self-balanced low-temperature ammonia reforming-based high-power hybrid power generation system combined with proton exchange membrane fuel cell and internal combustion engine

A 300 kW hybrid power generation system consisting of proton exchange membrane fuel cell and internal combustion engine based on low-temperature ammonia decomposition to produce hydrogen was proposed. A thermodynamics model was established to evaluate the energetic, exegetic, economic and environmental characteristics of the system. Then the power distribution of the proton exchange membrane fuel cell and internal combustion engine under variable load condition was optimized based on the updated sparrow search algorithm. The results show that the energy and exergy efficiency of the system at the rated output power are 42.2% and 37.13%, respectively. Furthermore, the optimal output power curves of proton exchange membrane fuel cell and internal combustion engine at different working conditions are obtained, and the energy efficiency reaches the optimal value 45.22% under the condition operating on 226 kW, while the exergy efficiency is 39.86%. According to the economic and environmental analysis, the levelized cost of energy and internal return rate for the hybrid system are $0.0874/kWh and 32.24%, respectively. When the proportion of green ammonia in the fuel reaches 0.8, the annual carbon emission of the system is 446 t, which reduces 1740 t emissions, and the carbon reduction rate is 79.6%.