NOVELTY - A thermally integrated system (300) for producing electricity using feedstock fuel as input comprises: reformer (302) having plasma zone to ionize pre-heated mixture of reactants (308, 310) by applying electrical potential to it and reaction zone to chemically transform reactants into synthesis gas (312), where each zone is surrounded by distinct thermally conductive surface that is directly exposed to external heat source; and fuel cell (304) to chemically convert gas to electricity and heat (306), where part of heat is transmitted via surface to provide heat of reformation to reactants.    USE - As thermally integrated system for producing electricity using a feedstock fuel as input (claimed); and as plasma-catalyzed, thermally integrated reformer for fuel cell systems.    ADVANTAGE - The system provides an improved system for generating reformate from various fuels that improves the Faradaic efficiency of fuel cells, such as solid oxide fuel cells (SOFCs), molten-carbonate fuel cells (MCFCs), or phosphoric acid fuel cells (PAFCs). The system is capable of reforming fuels with high sulfur content (e.g. 10000 ppm) without requiring sulfur pre-removal, while avoiding problems such as poisoning the catalyst or carbon buildup. The system improves the overall efficiency of fuel reformation and electricity production.    DETAILED DESCRIPTION - A thermally integrated system (300) for producing electricity using a feedstock fuel as an input, comprises: a reformer (302) comprising a plasma zone to ionize a pre-heated mixture of reactants (308, 310) by applying an electrical potential to it, and a reaction zone to chemically transform the ionized reactants into synthesis gas (312), where each of the plasma zone and reaction zone are surrounded by a distinct thermally conductive surface that is directly exposed to an external heat source; and a fuel cell (304) to chemically convert the synthesis gas to electricity and heat (306), where at least part of the heat is transmitted through the thermally conductive surface to provide at least part of the heat of reformation to the reactants. The reactants comprise a feedstock fuel and an oxidant. The thermally conductive surface is designed with a surface area sufficient to collectively transfer 2-30% of the heating value of the feedstock fuel, present in the reformer, into the plasma and reaction zones to provide the heat of reformation.    DESCRIPTION OF DRAWING(S) - The figure shows high-level block diagram of a reformer.    System (300)    Plasma reformer (302)    Fuel cell (304)    Heat (306)    Reactants (308, 310)    Synthesis gas (312)