Stationary combined heat and power (CHP) fuel cell systems (FCSs) can provide electricity and heat for buildings and can reduce greenhouse gas (GHG) emissions significantly if they are configured with an appropriate installation and operating strategy. The maximizing emission reduction and economic saving simulator (MERESS) is an optimization tool that was developed to evaluate novel strategies for installing and operating CHP FCSs in buildings. These novel strategies include networking, load following, and the use of variable heat-to-power ratios, all of which industry typically has not implemented. A primary goal of models like MERESS is to use relatively inexpensive simulation studies to identify more financially and environmentally effective ways to design and install FCSs. Models like MERESS can incorporate the pivotal choices that FCS manufacturers, building owners, emission regulators, competing generators, and policy makers make, and empower them to evaluate the effect of their choices directly. MERESS directly evaluates trade-offs among three key goals: GHG reductions, energy cost savings for building owners, and high sales revenue for FCS manufacturers. MERESS allows one to evaluate these design trade-offs and to identify the optimal control strategies and building load curves for installation based on either (1) maximum GHG emission reductions or (2) maximum cost savings to building owners. Part I discusses the motivation and key assumptions behind MERESS model development. Part II discusses run results from MERESS for a California town and makes recommendations for further FCS installments (Colella, 2011, “Optimizing the Design and Deployment of Stationary Combined Heat and Power Fuel Cell Systems for Minimum Costs and Emissions—Part II: Model Results,” ASME J. Fuel Cell Sci. Technol., 8(2), p. 021002).