Molten carbonate fuel cell (MCFC)/gas turbine (GT) hybrid system has attracted a great deal of research effort due to its higher electricity efficiency. However, its technology has remained at the conceptual level due to incomplete examination of the related issues, challenges and variables. To contribute to the development of system technology, the MCFC/GT hybrid system is analyzed and discussed herein. A qualitative comparison of the two kinds of MCFC/GT hybrid system, indirect and direct, is hindered by the many variables involved. However, the indirect system may be preferred for relatively small-scale systems with the micro-GT. The direct system can be more competitive in terms of system efficiency and GT selection due to the optionality of system layouts as well as even higher GT inlet temperature. System layout is an important factor influencing the system efficiency. The other issues such as GT selection, system pressurization and part-load operation are also significant. (C) 2011 Elsevier Ltd. All rights reserved.