The present paper unveils the technology developed for a series hybrid battery-dominant electric-hydrogen fuel cell plug-in city bus. It possesses a homemade power train with three electric energy sources, which are the grid-charged energy, the one produced by the fuel cell that works at constant power and acts as a range extender and that resultant from the regeneration of kinetic energy. Emphasis was given to the design of the hybridization energy engineering that has predominance of power in batteries and predominance of energy with hydrogen. The remarkable amount of 46.6% of the total energy input reaches the motor axle for effective motion and a fuel economy of 6.7 kg H-2/100 km was achieved. A total owner cost analysis has shown that computation of capital, operational and fueling costs makes the present bus 133% more expensive than a conventional diesel powered one. Commercialization prospects, and also social and environmental impacts are analyzed. (C) 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.