Using modeling and thermal simulations, the feasibility of an adsorption-based hydrogen storage system for vehicles is evaluated. The storage capacity of a 150 L tank filled with a high surface-area activated carbon is mapped for temperatures from 60 to 298 K and pressures up to 35 MPa. The thermal simulations are verified using experiments. For a storage capacity target of 5 kg, the adsorption-based storage System will offer a storage advantage over the cryogenic gas storage if the residual mass of hydrogen in the tank is retrieved by heating. For a discharge rate of 1.8 g/s, the required heat is of the order of 500 W. The net energy requirements for the refueling has, contributions from compression, precooling and tank cooling and can approach that for liquid hydrogen storage. With a good insulation and a maximum tank pressure of 35 MPa, the dormancy period can be extended to several weeks. (C) 2009 American Institute of Chemical Engineers AIChE J, 55: 2985-2996, 2009