Optimal sizing and dispatch of onsite PV electrolysis hydrogen storage for industrial decarbonization: supply chain embodied carbon and economy wide impacts

Current plant-level industrial decarbonization studies evaluating onsite renewables and storage often overlook broader supply chain and economy-wide impacts. This study proposes an integrated decision framework coupling a multi objective mixed integer linear programming model for onsite photovoltaic, electrolysis, hydrogen storage, and fuel cell with environmentally extended input output (EEIO) accounting. The optimization minimizes life cycle system cost, reduces grid CO2 emissions, and generates a Pareto frontier across increasing levels of grid displacement for a representative small and medium sized manufacturer. Results reveal strongly nonlinear tradeoffs: photovoltaic dominant designs deliver substantial emissions reductions at relatively low incremental cost, whereas deeper decarbonization requires hydrogen production and large storage capacity, leading to diminishing marginal abatement returns and sharply rising capital intensity. To quantify broader consequences, selected Pareto solutions are evaluated in a national domestic EEIO model to estimate sectoral output, value added, and embodied greenhouse gas emissions attributable to the required equipment and balance of plant components. Embodied emissions increase disproportionately as storage scales, but cumulative avoided operational CO2 over the project life remains larger even in near zero grid use scenarios, indicating net climate benefits alongside upstream impact shifts. By linking operationally feasible design and dispatch decisions with supply chain and economy wide metrics, the framework provides a case-based decision support approach for industrial decarbonization planning. The quantitative results are specific to a representative Ohio SMM under the adopted U.S. modeling boundary, while the broader value of the study lies in revealing the directional trade-offs associated with deeper electrification.