A refrigeration system comprising: an engine; an electric generator mechanically coupled to the engine to be driven by the engine; a compressor, electrically coupled to the generator to be powered by the generator; a heat rejection heat exchanger coupled to the compressor to receive compressed refrigerant from the compressor; an expansion device coupled to the heat rejection heat exchanger to expand refrigerant received from the heat rejection heat exchanger; a heat absorption heat exchanger coupled to the expansion device to receive refrigerant expanded by the expansion device and, in turn, coupled to the compressor to return refrigerant to the compressor; at least one first electric fan positioned to drive an airflow across the heat rejection heat exchanger and coupled to the generator to receive electric power from the generator; at least one second electric fan positioned to drive an airflow across the heat absorption heat exchanger and coupled to the generator to receive electric power from the generator; and a controller coupled to the compressor and the at least one first and second fans (129,149) and configured to: start the engine; and characterised in that the controller is further configured to engage the generator and at least one of the at least one first fans to be powered by the generator before the engine has reached running speed; after the engine has reached running speed, start the compressor; and after starting the compressor, start at least one of the at least one second fans. an engine; an electric generator mechanically coupled to the engine to be driven by the engine; a compressor, electrically coupled to the generator to be powered by the generator; a heat rejection heat exchanger coupled to the compressor to receive compressed refrigerant from the compressor; an expansion device coupled to the heat rejection heat exchanger to expand refrigerant received from the heat rejection heat exchanger; a heat absorption heat exchanger coupled to the expansion device to receive refrigerant expanded by the expansion device and, in turn, coupled to the compressor to return refrigerant to the compressor; at least one first electric fan positioned to drive an airflow across the heat rejection heat exchanger and coupled to the generator to receive electric power from the generator; at least one second electric fan positioned to drive an airflow across the heat absorption heat exchanger and coupled to the generator to receive electric power from the generator; and a controller coupled to the compressor and the at least one first and second fans (129,149) and configured to: start the engine; and characterised in that the controller is further configured to engage the generator and at least one of the at least one first fans to be powered by the generator before the engine has reached running speed; after the engine has reached running speed, start the compressor; and after starting the compressor, start at least one of the at least one second fans. start the engine; and characterised in that the controller is further configured to engage the generator and at least one of the at least one first fans to be powered by the generator before the engine has reached running speed; after the engine has reached running speed, start the compressor; and after starting the compressor, start at least one of the at least one second fans.