According to Mercedes, the next generation S-Class will launch with a plug-in hybrid model available immediately.

As Thomas Weber of Mercedes research and development said in an interview with Autocar, "It makes a lot of sense to bundle the high-price tech option to the sort of customers willing to pay for this sort of thing."

The S-Class will be the first Mercedes plug-in hybrid model, but the technology will slowly makes its way down through the range of the companies lineup of vehicles.  By starting at the top of the model lineup, additional costs of the plug-in hardware have less impact on the overall price of the vehicle.

The next S-Class will see improvements in aerodynamics as well as a reduction in weight which should help the plug-in version achieve strong fuel economy.  Mercedes has hinted at numbers of over 80mpg in normal driving with CO2 emissions around 100g/km.

As for a fully electric version of a Mercedes model, the company say this will not happen anytime soon.  As Weber said, "It could be possible, but no.  Our customers expect a certain range and a level of comfort, safety, and space; such things lead to a certain weight and that won't mean a good range."

Perhaps as technology advances, Mercedes will consider an EV, but for now the plug-in hybrid looks impressive.  As the PHEV spreads across the Mercedes lineup of vehicles, fitment into smaller models will likely result in even better economy numbers.

For now we eagerly anticipate the arrival of the next generation S Class PHEV in 2012.