A thermoelectric generator, comprising the following elements: - a heat distributor having a longitudinal internal passage with a heat sink for guiding a hot gas stream from an inlet of the heat distributor to an outlet of the heat distributor, the heat sink comprises several ribs where the hot gas stream passes between them from the heat distributor inlet to the heat distributor outlet, where the heat distributor inlet is connected to the heat distributor by means of a first lid and a first sealing, and the heat distributor outlet is connected to the heat distributor by means of a second lid and a second sealing; - at least two thermoelectric elements placed and connected diametrically to each other to the heat distributor, where each thermoelectric element has a hot side and a cold side, where the hot side is connected to the heat distributor and the cold side is connected to a water cooler block with an inlet cooler connection and outlet cooler connection, the water cooler block comprises a cooler base with a plurality of cooler pins extending from the cooler base to a cooler base lid connected to the inlet cooler connection and the outlet cooler connection; characterized in that - the heat distributor is extruded in one piece having a quadratic shape and where each internal wall is provided with the heat sink comprising ribs of different heights such that the cross section of the heat distributor has ribs making a star shaped pattern; - the cooler pins extend from the cooler base to a cooler base lid have a rectangular shape; - pressure pads are connected to tightening screws supported by a fitting ring, for pressing the water cooler blocks against the at least two thermoelectric elements; - a first water pipe is connected to the inlet cooler connection of each water cooler block, and a second water pipe connected to the outlet cooler connection of each water cooler block; said elements are enclosed in a housing provided with a bushing for electrical connections to the thermoelectric elements; and where a material having low thermal conductivity is provided between the housing and the heat distributor. - a heat distributor having a longitudinal internal passage with a heat sink for guiding a hot gas stream from an inlet of the heat distributor to an outlet of the heat distributor, the heat sink comprises several ribs where the hot gas stream passes between them from the heat distributor inlet to the heat distributor outlet, where the heat distributor inlet is connected to the heat distributor by means of a first lid and a first sealing, and the heat distributor outlet is connected to the heat distributor by means of a second lid and a second sealing; - at least two thermoelectric elements placed and connected diametrically to each other to the heat distributor, where each thermoelectric element has a hot side and a cold side, where the hot side is connected to the heat distributor and the cold side is connected to a water cooler block with an inlet cooler connection and outlet cooler connection, the water cooler block comprises a cooler base with a plurality of cooler pins extending from the cooler base to a cooler base lid connected to the inlet cooler connection and the outlet cooler connection; characterized in that - the heat distributor is extruded in one piece having a quadratic shape and where each internal wall is provided with the heat sink comprising ribs of different heights such that the cross section of the heat distributor has ribs making a star shaped pattern; - the cooler pins extend from the cooler base to a cooler base lid have a rectangular shape; - pressure pads are connected to tightening screws supported by a fitting ring, for pressing the water cooler blocks against the at least two thermoelectric elements; - a first water pipe is connected to the inlet cooler connection of each water cooler block, and a second water pipe connected to the outlet cooler connection of each water cooler block;