This paper presents an energy demand model for a fleet of plug-in fuel cell vehicles and a medium-sized commercial/office building interfaced with a clean energy hub. The approach taken is to model the architecture and daily operation of every individual vehicle in the fleet. A simplified architecture model was developed, with daily operation divided into two periods: charging and travelling. During the charging period, the vehicle charges its batteries and refills its compressed hydrogen tanks. During the travelling period, the vehicle depletes the batteries and hydrogen tanks based on distance travelled. Daily travel distance is generated by a stochastic model. The modeling of the clean energy hub is also presented. The clean energy hub functions as an interface between electricity supply and the energy demand (i.e. hydrogen and electricity) of the vehicle fleet and the commercial building. Finally, a sample case is presented to demonstrate the use of the models. (C) 2009 Professor T. Nejat Veziroglu. Published by Elsevier Ltd. All rights reserved.