Non-pollution motor units, wherein a cryogenic liquid, such as liquid nitrogen, is evaporated to drive a gas motor, the gas motor in turn driving an alternator (electrical generator) the output from which is used to drive an electric drive motor. The electric drive motor and alternator are operated at very low temperatures so that their operating characteristics are greatly improved, evaporation of the cryogenic liquid being used to achieve the cooling. In the motor units, the gas motor, alternator and electric drive motor are preferably mounted within an insulated case or housing cooled by flowing the cryogenic liquid therethrough. The electric drive motor is useful to drive any driven equipment, of whatever character, without pollution of the environment.