NOVELTY - The device comprises a fuel cell admitting a mixture of methane and water steam as fuel (3) at a predetermined temperature and pressure, and a unit for transforming a gas mixture of ethanol and water into a mixture of methane and water steam for feeding the battery, which is used as secondary source of energy. The pressure of the methane gas mixture and water steam obtained from the transforming unit is 10-40 bar, and the pressure of the methane gas mixture and water steam obtained from the transforming unit is greater than 2 bar. The transformation unit is a reformer.    USE - The device is useful for producing electricity from heat and/or methane, and in a seawater desalinating device and a device for ethanol dehydration, where the methane produced by the transformation unit is useful for supplying a fuel cell admitting methane as fuel fed by a primary source of methanization allowing the variations in flow of digesters and for stabilizing the supply of methane (all claimed).    ADVANTAGE - The device exhibits excellent thermodynamic and operational efficiency, ensures larger production of electricity with less consumption of methane, and avoids the degradation of the catalyst during production of energy.    DETAILED DESCRIPTION - The device comprises a fuel cell admitting a mixture of methane and water steam as fuel (3) at a predetermined temperature and pressure, and a unit for transforming a gas mixture of ethanol and water into a mixture of methane and water steam for feeding the battery, which is used as secondary source of energy. The pressure of the methane gas mixture and water steam obtained from the transforming unit is 10-40 bar, and the pressure of the methane gas mixture and water steam obtained from the transforming unit is greater than 2 bar. The transformation unit is a reformer. The pressure of the methane gas and water steam mixture exiting the reformer is equal to the pressure of the mixture admitted by the reformer. A unit is arranged for pressurizing the liquid mixture of ethanol and water and providing a pressurized gas mixture of ethanol and water at pressure higher than the methane mixture and water vapor admitted by the fuel cell. A unit is arranged for heating the pressurized gas mixture of ethanol and water. A unit is arranged between the transformation unit and the battery for conversion of turbine (15) into electricity. The temperature of the methane and steam produced by the reformer is greater than the mixture of methane and water vapor admitted by the battery. A first heat exchanger (18) is interposed between the reformer and the battery. The reformer comprises a nickel catalytic bed, and allows to provide an exothermic reaction, where the heat released by the exothermic reaction is transferred through the heat exchanger towards the mixture of ethanol and water admitted to the reformer to heat the mixture. A second heat exchanger (21) is used for transferring the heat produced by the fuel cell to the mixture of water and ethanol admitted to the transformation unit. A third heat exchanger is arranged between a second part of the heat produced by the high temperature battery and a first heat receiver. The first heat receiver is a turbine for converting the second part of the heat produced by high temperature battery and/or the third heat exchanger into electricity. A unit is arranged for recirculation of the gas mixture produced by the battery towards the mixture of water and ethanol feeding the transformation unit. The recirculation unit comprises a device for purifying gas mixture for eliminating undesirable gaseous compounds from gas mixture such as carbon dioxide.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view of a device for production of energy.    Fuel (3)    First source of energy (10)    Turbine (15)    Methane rich gaseous mixture (16)    First heat exchanger (18)    Second heat exchanger. (21)