A turbine assembly for an internal combustion engine having: a first turbine that rotates around a first rotation axis and is configured to rotate due to the thrust exerted by exhaust gases emitted by the internal combustion engine; a second turbine which is independent of and separate from the first turbine, rotates around a second rotation axis parallel to and spaced from the first rotation axis, and is configured to rotate due to the thrust exerted by exhaust gases emitted by the internal combustion engine; an electric generator operated by the first turbine; and a transmission device that connects both the turbines to the same electric generator.