This report prepared by the Lawrence Berkeley National Laboratory describes a total cost of ownership model for emerging applications in stationary fuel cell systems, specifically high temperature proton exchange membrane systems for use in combined heat and power applications from 1 to 250 kilowatts-electric. The total cost of ownership framework expands the direct manufacturing cost modeling framework of other studies to include operational costs, life-cycle impact assessment of possible ancillary financial benefits during operation and at end-of-life, including credits for reduced emissions of global warming gases, such as carbon dioxide (CO2) and methane (CH4), reductions in environmental and health externalities, and end-of-life recycling. This project cost study considers both externalities and ancillary financial benefits, and thus provides a comprehensive picture of fuel cell system benefits, consistent with a policy and incentive environment that increasingly values these ancillary benefits.