Health-Aware Dynamic Operation of PEM Electrolyzers: A Techno-Environmental Optimization for Carbon-Matched Hydrogen Production

Hydrogen is increasingly positioned as a strategic energy carrier for decarbonizing hard-to-abate sectors, yet the actual performance of electrolytic hydrogen depends on how electrolyzers interact with renewable electricity, carbon accounting rules, storage limits, and stack degradation. This study develops a calibrated health-aware carbon-matched dispatch framework for proton exchange membrane (PEM) electrolysis. The model integrates hourly renewable generation, grid carbon intensity, part-load operation, start-stop degradation, hydrogen storage, and system cost in a single techno-environmental optimization structure. A reference 10 MW PEM electrolyzer coupled with solar and wind generation is simulated over 8760 hourly periods and assessed under four operating strategies: baseload grid-assisted electrolysis, price-only flexible operation, carbon-aware flexible operation, and the proposed health-aware carbon-matched strategy. To strengthen robustness, the model is calibrated against external PEM electrolysis techno-economic and operational benchmarks and then stress-tested under conservative efficiency, low-degradation, and strict-carbon scenarios. Results show a sharp trade-off. Baseload operation yields the lowest apparent levelized cost of hydrogen, 4.58 USD kg H2−1, but produces high operational emissions, 4.887 kg CO2 kg H2−1. Carbon-aware flexible operation cuts emissions, but suffers from low utilization and frequent shutdowns. The proposed health-aware carbon-matched strategy reduces operational emissions to 0.027 kg CO2 kg H2−1, maintains 99.8% direct use of renewable electricity, and lowers the levelized cost of hydrogen (LCOH) by about 31% relative to the carbon-aware flexible benchmark. The central finding is direct: flexibility alone is not enough. Renewable hydrogen systems must be operated to respect both hourly carbon conditions and stack health. Within the operational electricity-related boundary, this produces hydrogen with lower reported emissions, fewer damaging operating events, and stronger techno-economic credibility. The reported emissions are not cradle-to-grave lifecycle emissions; conclusions about full environmental superiority require a dedicated lifecycle assessment.