Two SOFC systems with CO2 capture, i.e., SOFC with CO2 capture from biogas feed (biogas-cap SOFC) and SOFC with CO2 capture from reformed gas (reformed gas-cap SOFC) have been investigated. Employing the sweep gas to increase the gas separation capability, both systems offered higher power density but lower electrical efficiency than those of the SOFC without CO2 capture (non-cap SOFC). The installation of a vacuum pump can improve the electrical efficiency of the biogas-cap, SOFC but not for the reformed gas-cap SOFC. Economic analysis revealed that the biogas-cap SOFC with vacuum pump installation is superior to the other SOFC systems. (c) 2008 Elsevier B.V. All rights reserved.