The art and science of computer simulation are making important contributions to the development of lower-cost, higher-efficiency, solid-state fuel cell systems, and those contributions are expected to grow rapidly as more accurate and robust models are developed. In support of the Solid State Energy Conversion Alliance, and building on previous work with one-dimensional codes, researchers at DOE’s National Energy Technology Laboratory are developing tools for full 3-D analysis of complex solid-state fuel cell geometries. Unlike simpler tools, the FLUENT-based 3-D analysis tools provide designers with performance predictions, thermal stress distributions and the ability to explore complex design options in a rapid, cost-effective manner.