System und Verfahren zum Betreiben von Festoxidbrennstoffzellen

The invention relates to a system and to a method for operating solid oxide fuel cells. The aim of the invention is to specify possibilities for a variable operation of solid oxide fuel cells, by means of which the respective current demand for electrical power and/or usable waste heat can be taken into account with simple means and low additional overheads. In the system according to the invention, fuel and/or reformate is supplied to a stack of solid oxide fuel cells on the anode side via a reformer. The reformer can be heated by means of hot exhaust gas from the solid oxide fuel cells. Moreover, at least one heat exchanger is present in the exhaust gas line for external use of the waste heat of the solid oxide fuel cells. In addition to the supplied fuel, an oxidant, preferably air, is supplied in a regulated form via a line to the reformer