The reduction of CO2 emissions, considering its greenhouse effect, and primary energy saving are ones of the most important challenges for the worldwide scientific community. The study of power plants with reduced CO2 emission factor (EF), through the achievement of higher conversion efficiency and switching to less carbon intense fuels, can significantly contribute to the these targets. In this scenario, fuel cells (FCs) technology can represent an alternative to traditional power generation systems; it offers the potential for higher electrical efficiencies and lower emissions. In particular, high temperature solid oxide fuel cells (SOFCs), thanks to their favorable characteristics as high efficiency, reaction kinetics, power density, and usable heat, beyond that fuel flexibility, are considered to be one of themost promising technologies for future power generation. Main advantages of high temperature FCs, respect to low temperature FCs, are represented by the possibility to use the produced heat (at operating temperatures typically over 600◦C) in both fuel-processing and heat-generation systems. They are, therefore, highlighted, respect to low temperature FCs: • potential to be independent from a pure hydrogen infrastructure and, therefore, fuel flexibility and application in transitional fuels such as natural gas, syngas, and biogas; • unsurpassed efficiencies, approaching 90% total efficiency (electrical and thermal), in cogenerative applications.