A 24 kW, 30% efficient gas turbine-driven generator set is being developed for hybrid electric vehicles. With the generator mounted on the same shaft as the compressor and the turbine, the rotor group is the only moving part other than the fuel pump. There are no engine-driven accessories. There is no oil as the rotor is mounted on air bearings. There is no water or antifreeze as the generator set is air cooled. Orientation can be vertical or horizontal.Emission levels on unleaded gasoline, methanol, M85, ethanol or natural gas are much less than ULEV standards using a lean premix combustor. They are one or two orders of magnitude less than ULEV standards using a catalytic combustor. This paper addresses some of the design and application factors considered in developing the hardware.