NOVELTY - Thermoelectric power unit (18) comprises a thermoelectric device(s) including a bulk thermoelectric material (22), fluid passages (40, 42) on opposite sides of the thermoelectric device, and heat pipes.    USE - For a thermoelectric generator system (10) used, e.g. to convert thermal energy in an engine exhaust passage into electrical power; to produce power from a geothermal power source, cooling water from a nuclear plant, and/or hot gases released from a coal power plant; as an electric power source on an on-highway or off-highway trucks, trains, earthmoving equipment, airplanes, and/or boats.    ADVANTAGE - Thermoelectric power unit allows a large amount of thermal energy to be focused on a relatively small thermoelectric device, thus allowing efficient energy production with a high power density and decreasing the amount of expensive thermoelectric material required to meet electrical energy demands of mobile work machines. The thermoelectric power unit may be produced at lower cost than other generator systems.    DETAILED DESCRIPTION - Thermoelectric power unit comprises a thermoelectric device(s), a first fluid passage on a first side of the thermoelectric device to receive a hot exhaust stream, heat pipes to focus thermal energy from a fluid flowing through the first passage toward the first side of the thermoelectric device, and a second fluid passage on a second side of the thermoelectric device opposite of the first fluid passage and configured to conduct thermal energy away from the thermoelectric device. The fluid is water, engine coolant, or air. The thermoelectric device includes a thermoelectric material having a zero- dimensional quantum dot structure, one-dimensional nanowires structure, two-dimensional quantum well structure, a superlattice structure, or a nanocomposite thermoelectric structure. The thermoelectric device includes a bulk thermoelectric material. An INDEPENDENT CLAIM is included for a method of generating electric power.    DESCRIPTION OF DRAWING(S) - The figure shows an exploded view of the thermoelectric generator system.    Thermoelectric generator system (10)    Thermoelectric power unit (18)    Bulk thermoelectric material (22)    Fluid passages (40,42)