NOVELTY - An electric power generator (1) comprises means (2) for generating a gas fuel to be supplied to the stack (5), and means (7, 10) for removing at least part of a heat flow generated in the stack (5) as a consequence of the consumption of the gas fuel.    USE - The electric power generator is used to provide electrical energy.    ADVANTAGE - The fuel cell electric power generator of the type comprises on-site means for generating gaseous fuel, which makes it possible to simply and cost-effectively overcome the drawbacks associated with the known solutions. The fuel cell electric power generator of the type comprises on-site means for generating gas fuel, in particular for back-up applications, which is capable of meeting the energy and management requirements of the aforesaid system, while ensuring the possibility of limiting the overall size of the system and wisely managing the involved heat flows, both during the start-up phase of the various apparatus and during the corresponding full-capacity operating phase.    DETAILED DESCRIPTION - An electric power generator (1) comprises fuel cells stacked in a stack (5) and configured to supply an electric load (6). The generator (1) comprises means (2) for generating a gas fuel to be supplied to the stack (5), and means (7, 10) for removing at least part of a heat flow generated in the stack (5) as a consequence of the consumption of the gas fuel. The generator (1) comprises heating means (8, 9) configured to maintain the means (2) for generating gas fuel in a predetermined temperature range and comprising means (9) for transferring at least part of the removed part of the heat flow generated in the stack (5) from the removing means (7) to the means (2) for generating gas fuel. The means (7) for removing at least part of the heat flow generated in the stack (5) comprise a first hydraulic circuit thermally coupled to the stack (5) through which a flow of a first thermal carrier fluid passes and in that the heating means (8, 9) comprise a second hydraulic circuit (8) thermally coupled to the means (2) for generating gas fuel and through which a flow of a second thermal carrier fluid passes. An INDEPENDENT CLAIM is a method for managing an electric power generator having fuel cells stacked in a stack (5) and configured to supply an electric load (6).    DESCRIPTION OF DRAWING(S) - The drawing shows a diagrammatical view of a fuel cell electric power generator.    Electric power generator (1)    Means for generating a gas fuel (2)    Stack (5)    Electric load (6)    Means for removing heat flow (7, 10)    Heating means (8, 9)