The Solid Oxide Fuel Cells are made of ceramic materials and operate at very high temperatures, between 600 °C and 900 °C. The feature peculiar to these systems is that they can be fuelled by not only hydrogen, but also other fuels, such as natural gas, biogas, methane, bioethanol, etc. The SOFC system is suitable to be fuelled also by syngas, which is the result of the hydrocarbon reforming process with high molecular weight, diesel included. The new age of SOFC concerns the direct oxidation of organic fuels to avoid the reforming phase and lower the complexity of water management. This kind of fuel cells is employed with CHP (combined heat and power) cogeneration stationary systems and maritime transport.