This study examines the cost-effectiveness of heavy-duty, long-haul fuel cell electric vehicles (FCEVs) compared to conventional diesel trucks from a fleet operator’s perspective, using a techno-economic approach. Initially, a fuel cell stack component was integrated into a quasi-static simulation model to evaluate various truck configurations in terms of performance and energy consumption over a representative highway cycle for long-haul missions. The resulting simulations provided inputs for calculating the Total Cost of Ownership (TCO), allowing a precise assessment of energy carrier cost, based on simulated truck energy consumption, that is a critical cost type in FCEV truck economic evaluation. The TCO model includes several cost categories, including purchase costs, energy carrier costs, maintenance, taxes and tolls, driver expenses, and residual value.