3E assessment of centralized PV-powered green hydrogen polygeneration system: performance enhancing through waste heat recovery

Green hydrogen is essential for sustainable energy transitions, yet enhancing its performance remains challenging. Polygeneration systems integrating electricity, hydrogen, and heat represent a promising pathway, with waste heat recovery crucial for sustainability and economic viability. However, few studies have thoroughly evaluated its efficacy. This study presents a 3E (Energy-Economy-Environment) assessment of a centralized PV-powered green hydrogen polygeneration system incorporating waste heat recovery. An integrated simulation framework combines modeling, thermodynamic analysis, energy management strategy, and 3E evaluation. A novel rule-based daily generation-adaptive energy management strategy is proposed. Concurrently, the study introduces an environmental indicator, decarbonization efficiency index, to enable cross-project decarbonization benchmarking. The results show that waste heat recovery improves all 3E aspects: though the economic gains are modest with a 3.1% reduction in the payback period due to the low heat price, energy efficiency rises 11.9 percentage points, with 9.4% increases in both annual CO2 emission reductions and decarbonization efficiency index. Compared to traditional strategies, the proposed one achieves 100% load met rate and 98.1% energy efficiency, reduces payback period by 2.6% and 18.4%, cuts annual CO2 emissions by 4670 tons, and reaches a decarbonization efficiency index of 0.778 t/kW. This study provides guidance for the enhancement and evaluation of efficient, decarbonized polygeneration systems.