The benefits of a system combining high- and low-temperature fuel cell types have been assessed using computer predictions. A high-temperature solid oxide fuel cell (SOFC) may be used to produce electricity and carry out fuel reforming simultaneously. The exhaust stream from an SOFC can be processed by shift reactors and supplied to a low-temperature polymer electrolyte membrane (PEM) cell. The overall efficiency predicted for the hybrid system is shown to be significantly better than a Reformer-PEM system or an SOFC-only system. Approximate capital and running cost estimates also show significant benefits compared to the other two systems.