Solid-oxide fuel cells with ceria, ceria-Cu, and ceria-Rh anode were demonstrated to generate stable electric power with waste vegetable oil through direct oxidation of the fuel. The only pre-treatment to the fuel was a filtration to remove particulates. The performance of the fuel cell was stable over 100 h for the waste vegetable oil without dilution. The generated power was up to 0.25 W cm(-2) for ceria-Rh fuel cell. This compares favorably with previously studied hydrocarbon fuels including jet fuels and Pennsylvania crude oil. (C) 2007 Elsevier B.V. All rights reserved.