Steam reforming of bio-oil into transportation-fuel-grade hydrogen using CaO as a CO2 sorbent is modelled using the ASPEN PLUS process simulator. The simulations predict that (1) operating the absorbing (reforming) reactor at 600-850degreesC and the desorbing (regeneration) reactor at similar to 800degreesC and near ambient pressure is optimal; (2) the gas exiting the absorbing reactor contains > 95% H-2 (dry gas, molar basis) versus only 67% theoretically producible without the aid of sorbents; (3) hydrogen yield from the sorbent-aided system is comparable to that predicted for catalytic steam reforming of bio-oil without the use of sorbents, similar to 0.07-0.08 kg H-2 per kg of bio-oil. (C) 2003 International Association for Hydrogen Energy. Published by Elsevier Science Ltd. All rights reserved.