A Pre-Commissioning Engineering Digital Twin for Dispatch Assessment of an Integrated Renewable Hydrogen System

This study applies a pre-commissioning engineering digital twin to compare two electrolyzer operating policies for a renewable hydrogen hub in Zagreb, Croatia. Equipment-based component models represent renewable generation, battery storage, electrolysis, compression, hydrogen storage and internal use. Under matched annual scenario inputs, maximum-output and nominal-load operation yield reported hydrogen production of 188.71 and 134.67 kg/year, respectively, at variable operating costs of 18.19 and 18.02 €/kg. Across 500 paired weather realisations, maximum-output operation produces more hydrogen in every evaluated pair, with a median advantage of 54.2 kg/year (P10-P90: 52.9–55.4 kg/year). The corresponding median variable-cost premium is 0.170 €/kg. These results describe a conditional production–cost trade-off under the specified dispatch and weather assumptions. Daily battery initialisation and unresolved annual electrical and hydrogen-flow accounting limit interpretation of grid performance, storage feasibility and delivered service; these indicators are not used to establish policy superiority.