A method (300, 400) for preserving autonomous operation of a transport climate control system that includes a refrigeration circuit having a compressor, the refrigeration circuit providing climate control within an internal space of a transport unit using a transport power system that includes a controller, a prime mover (21, 87, 202), and an auxiliary energy storage, the method (300, 400) comprising: the controller determining whether a regulatory compliance at a current location is restricting and/or preventing the use of the prime mover (21, 87, 202) for powering the transport climate control system while the transport unit is in transit; when the controller determines that use of the prime mover (21, 87, 202) for powering the transport climate control system is not being restricted or prevented because of a regulatory compliance, operating the transport climate control system and the transport power system in an energy harvesting operation mode for storing excess power generated by the prime mover (21, 87, 202) into the auxiliary energy storage; and when the controller determines that use of the prime mover (21, 87, 202) for powering the transport climate control system is being restricted or prevented because of a regulatory compliance, the controller instructing the auxiliary energy storage to provide power to the transport climate control system; characterized in that operating the energy harvesting operation mode includes: the controller obtaining periphery power data regarding the transport power system when the transport climate control system does not have a refrigeration demand, wherein the periphery power data includes a charge rate of the auxiliary energy storage, the controller determining the prime mover (21, 87, 202) operation speed based on the periphery power data, the prime mover (21, 87, 202) operating at the determined prime mover (21, 87, 202) operation speed, the controller calculating the amount of excess power available (435, 480) from the prime mover (21, 87, 202), and storing the excess power in the auxiliary energy storage. the controller determining whether a regulatory compliance at a current location is restricting and/or preventing the use of the prime mover (21, 87, 202) for powering the transport climate control system while the transport unit is in transit; when the controller determines that use of the prime mover (21, 87, 202) for powering the transport climate control system is not being restricted or prevented because of a regulatory compliance, operating the transport climate control system and the transport power system in an energy harvesting operation mode for storing excess power generated by the prime mover (21, 87, 202) into the auxiliary energy storage; and when the controller determines that use of the prime mover (21, 87, 202) for powering the transport climate control system is being restricted or prevented because of a regulatory compliance, the controller instructing the auxiliary energy storage to provide power to the transport climate control system; characterized in that operating the energy harvesting operation mode includes: the controller obtaining periphery power data regarding the transport power system when the transport climate control system does not have a refrigeration demand, wherein the periphery power data includes a charge rate of the auxiliary energy storage, the controller determining the prime mover (21, 87, 202) operation speed based on the periphery power data, the prime mover (21, 87, 202) operating at the determined prime mover (21, 87, 202) operation speed, the controller calculating the amount of excess power available (435, 480) from the prime mover (21, 87, 202), and the controller obtaining periphery power data regarding the transport power system when the transport climate control system does not have a refrigeration demand, wherein the periphery power data includes a charge rate of the auxiliary energy storage, the controller determining the prime mover (21, 87, 202) operation speed based on the periphery power data, the prime mover (21, 87, 202) operating at the determined prime mover (21, 87, 202) operation speed, the controller calculating the amount of excess power available (435, 480) from the prime mover (21, 87, 202), and storing the excess power in the auxiliary energy storage.