Power generator set comprising, in a soundproof container of standardized dimensions formed by two longitudinal walls (2, 4) with a length of the order of 6 meters, two side walls (3, 5) with a length of the order of 2.4 meters, a base and a top wall, a heat engine and an alternator connected to said heat engine to enable the conversion of the energy received from said heat engine into electrical energy, characterized in that it implements two air circulation circuits: - a first cooling circuit for cooling the power radiated by said engine, comprising: - at least three air inlets (A1, A2, A3, A4) distributed on a first side of said container, on a first of said side walls (3, 5) and said longitudinal walls (2,4); - at least two elements for distributing air received through said air inlets, delivering the air to said engine and said alternator respectively at the lower part and at the upper part of said container; - at least two first air outlets (A10, A11) formed in said upper wall on the second side of said container, in the vicinity of at least one exhaust silencer (131, 132) of said engine, said silencer (131, 132) being mounted substantially vertically, so as to be cooled by the air directed towards said outlets; - a second circuit for the thermal cooling of said engine, comprising: - at least three radiators, distributed on the second side of said container, respectively on the second of said side walls and said longitudinal walls; - at least one second air outlet (B11, B 13) formed in said top wall on the second side of said container; - at least one air extraction fan mounted in the vicinity of said air outlet. - a first cooling circuit for cooling the power radiated by said engine, comprising: - at least three air inlets (A1, A2, A3, A4) distributed on a first side of said container, on a first of said side walls (3, 5) and said longitudinal walls (2,4); - at least two elements for distributing air received through said air inlets, delivering the air to said engine and said alternator respectively at the lower part and at the upper part of said container; - at least two first air outlets (A10, A11) formed in said upper wall on the second side of said container, in the vicinity of at least one exhaust silencer (131, 132) of said engine, said silencer (131, 132) being mounted substantially vertically, so as to be cooled by the air directed towards said outlets; - at least three air inlets (A1, A2, A3, A4) distributed on a first side of said container, on a first of said side walls (3, 5) and said longitudinal walls (2,4); - at least two elements for distributing air received through said air inlets, delivering the air to said engine and said alternator respectively at the lower part and at the upper part of said container; - at least two first air outlets (A10, A11) formed in said upper wall on the second side of said container, in the vicinity of at least one exhaust silencer (131, 132) of said engine, said silencer (131, 132) being mounted substantially vertically, so as to be cooled by the air directed towards said outlets; - a second circuit for the thermal cooling of said engine, comprising: - at least three radiators, distributed on the second side of said container, respectively on the second of said side walls and said longitudinal walls; - at least one second air outlet (B11, B 13) formed in said top wall on the second side of said container; - at least three radiators, distributed on the second side of said container, respectively on the second of said side walls and said longitudinal walls; - at least one second air outlet (B11, B 13) formed in said top wall on the second side of said container; - at least one air extraction fan mounted in the vicinity of said air outlet.