at higher temperatures than the bilayered electrolyte model, closer to 600 °C rather than 500 °C. Currently, given the state of the field for LT-SOFCs, progress in the electrolyte would reap the most benefits, but research into potential anode and cathode materials would also lead to useful results, and has started to be discussed more frequently in literature. SOFC-GT An SOFC-GT system is one which comprises a solid oxide fuel cell combined with a gas turbine. Such systems have been evaluated by Siemens Westinghouse and Rolls-Royce as a means to achieve higher operating efficiencies by running the SOFC under pressure. SOFC-GT systems typically include anodic and/or cathodic atmosphere recirculation, thus increasing efficiency. Theoretically, the combination of the SOFC and gas turbine can give result in high overall (electrical and thermal) efficiency. Further combination of the SOFC-GT in a combined cooling, heat and power (or trigeneration) configuration (via HVAC) also has the potential to yield even higher thermal efficiencies in some cases. Another feature of the introduced hybrid system is on the gain of 100% CO2 capturing at comparable high energy efficiency. These features like zero CO2 emission and high energy efficiency make the power plant performance noteworthy. DCFC For the direct use of solid coal fuel without additional gasification and reforming processes, a direct carbon fuel cell (DCFC) has been developed as a promising novel concept of a high-temperature energy conversion system. The underlying progress in the development of a coal-based DCFC has been categorized mainly according to the electrolyte materials used, such as solid oxide, molten carbonate, and molten hydroxide, as well as hybrid systems consisting of solid oxide and molten carbonate binary electrolyte or of liquid anode (Fe, Ag, In, Sn, Sb, Pb, Bi, and its alloying and its metal/metal oxide) solid oxide electrolyte. People's research on DCFC with GDC-Li/Na2CO3 as the electrolyte, Sm0.5Sr0.5CoO3 as cathode shows good performance. The highest power density of 48 mW*cm−2 can be reached at 500 °C with O2 and CO2 as oxidant and the whole system is stable within the temperature range of 500 °C to 600 °C. SOFC operated on landfill gas Every household produces waste/garbage on a daily basis. In 2009, Americans produced about 243 million tons of municipal solid waste, which is 4.3 pounds of waste per person per day. All that waste is sent to landfill sites. Landfill gas which is produced from the decomposition of waste that