A direct formic acid fuel cell (DFAFC) hybrid power system for a laptop computer has been developed at the Korea Institute of Science and Technology, Fuel Cell Research Center. At the heart of the system is a 15 MEA DFAFC stack capable of 30 W at 60 mW cm(-2). Stack characteristics relevant to integration into the power system such as concentration and orientation dependence, dynamic response, and long-term performance are elucidated and the resulting hybrid power system's performance is detailed. The stack's fast dynamic response eliminated the need for significant power buffering in the power conditioning equipment. The MEAs were found to give reduced but stable performance after 3 months of operation. The system is capable of an overall system efficiency of 0.23 (delivered power compared to theoretical power), and can operate under a substantial computing load for 2.5 h using a 280 mL tank of 50 wt.% fuel. (c) 2006 Elsevier B.V All rights reserved.