Techno-economic optimization of a modular PEM electrolysis system for distributed hydrogen production

The accelerating deployment of renewable energy systems has intensified interest in green hydrogen as a flexible, low-carbon energy carrier, yet high capital costs (CAPEX) and exposure to renewable intermittency continue to constrain the economic viability of centralized hydrogen production. Here we present a modular, mobile 25-kW truck-deployable proton exchange membrane electrolysis (PEME) system designed to enable flexible, distributed hydrogen generation under variable renewable electricity supply. We develop a system-level techno-economic framework that integrates capacity configuration, renewable coupling, transportation impacts, and uncertainty analysis across six energy supply configurations. Our results show that modular deployment can substantially reduce upfront CAPEX requirements by ∼USD 400k or RMB 2.62 million through reduced land use, site development, and installation costs. Among the evaluated configurations, hybrid PV–WT supply achieves the lowest levelized cost of hydrogen (LCOH) under off-grid operation (USD 3.55 or 25.17 RMB per kg), while grid-connected WT electricity yields the lowest LCOH overall (USD 2.92 or 20.55 RMB per kg). Sensitivity and Monte Carlo uncertainty analyses reveal that LCOH is dominated by electrolyzer and renewable generation and are strongly influenced by the stability of renewable electricity supply. These findings demonstrate that modular PEM electrolysis can deliver cost-competitive and deployment-flexible hydrogen production in resource-rich but infrastructure-limited regions, providing a quantitative basis for designing distributed green hydrogen systems that reduce investment risk.