Fast realized for Emerson Process Management a complete supervision and control system based on DeltaV Emerson platform for a power supply plant in San Augustin de Guadalix (Madrid, Spain). The plant has been realized by Ansaldo with the Molten Carbonate Fuel Cells (MCFC) technology, with a power of 500KW and its peculiarity is the high degree of innovation: the hydrogen fuel cells are a very good answer to the future needs of the power supply market thanks to the high termal efficiency and the very low environmental impact, and to the ease in extracting the exaust CO2 for a subsequent treatment; the MCFC cells have an high flexibility since they have a multifuel capability, that is they can use not only hydrogen as a fuel but also other gases. The Fast supply includes the electrical cabinets for the process management and for the safety system and, most important, the software development for DCS system together with the realization of the graphical supervision pages for all the plant areas. Because of the peculiarity of the system, the software development required a modular architecture to guarantee an high flexibility in order to make easy and low cost (in terms of time and money) the opportunity of modifying the system "on the field" to answer the needs of a evolving structure.