How Stack Degradation Drives the Levelized Cost of Green Hydrogen: Techno-Economic, Water and Carbon Assessment of the CH2V PEM Pilot Plant

The Brazilian low-carbon hydrogen framework (Law 14948/2024) and pilot initiatives such as the UNIFEI Green Hydrogen Center (CH2V) are accelerating PEM water electrolysis deployment. Over multi-year horizons, an electrolyzer’s economic performance depends on capital, electricity, and stack degradation, which raises voltage or specific energy consumption and forces stack replacement. This paper presents SIGAH2V, an integrated decision-support tool, applied to a 50 Nm3/h PEM system at the CH2V plant to quantify degradation’s impact on the levelized cost of hydrogen (LCOH). Three configurations are compared (no degradation, voltage rise, SEC-based) under identical conditions. Under the adopted parameter set, plant-gate LCOH rises from €7.92/kg to €9.75/kg (+23.1%) and €10.67/kg (+34.7%); the two active cases are treated as scenario-based projections bracketing the degradation penalty rather than field-validated predictions. Stack replacement becomes a major cost component (19–26% of annual cost), shifting the driver away from electricity. Monte Carlo (20,000 runs), break-even, and economy-of-scale analyses show degradation raises LCOH in 100% of cases, with penalties shrinking at larger scales. Water footprint and carbon intensity remain identical.