That's for a belt-driven A/C, tied directly to the engine RPM. They're inherently much less efficient because they have to work over a wide range of speeds. A motor-driven A/C will be 1-2 kW.

That's also the peak power, and a motorized A/C will instead be turned on and off leading to a much lower power draw that also depends less on the peak power. Typically a 50-30% duty cycle, so 200-300 watts very roughly. More depending on the insulation, sun, and outside temperature.