That said, compared to other large luxury sedans, the S-Class can be pretty green—if you get the right model, that is. The S400 Hybrid, with its V-6 engine and lithium-ion-based hybrid system, doesn't make a lot of compromises yet it returns an EPA-estimated 19 mpg city, 25 highway.
On the other hand, pick any of the other V-8 S-Class models—especially one of the high-performance AMG models—and the ratings are enough to stoke any righteous environmentalist's rage. City ratings range down to a paltry 12 mpg in the city for the S65 AMG, and are at best (among V-8 models) 15 mpg city for the rear-wheel-drive S550.
On the bright side, the S-Class models do score pretty well for smog-forming emissions; despite its low mileage, the S65 earns a 6 out of 10 on the EPA Air Pollution Score.