While Mercedes-Benz and other German luxury automakers (Audi, especially) are betting on diesel powertrains on a larger scale in helping to make their lineups more fuel-efficient, they're starting to concede that to some luxury shoppers, plug-in hybrids are seen as a 'greener' solution—especially in tight urban spaces.

That's where the Mercedes-Benz S500 Plug-In Hybrid fits into the lineup. And in a roundtable interview at the Detroit Auto Show this past week, Prof. Dr. Thomas Weber, Daimler AG management board member and research and development chief for Mercedes-Benz cars, confirmed that this model is on track to go on sale late this year in Europe, and in early 2015 for the U.S.

“We are convinced that especially in the S-Class, the future of the plug-in concept will play a major role in congested areas for example, in areas and countries where special tax consideration is in place,” said Weber, who promised “a lot of driving pleasure” out of the plug-in.

Up against Panamera S e-Hybrid, with 20 miles or more all-electric

As first detailed this past summer, the all-new plug-in hybrid S-Class picks up on the Vision S500 concept of a few years ago—and should go head to head with the Porsche Panamera S e-Hybrid.

With a 328-horsepower, turbocharged 3.0-liter V-6 gasoline engine and 80-kW electric motor system, the S500 Plug-In Hybrid can accelerate the S-Class to 60 mph in about 5.5 seconds. A lithium-ion battery pack mounted in back should involve only minimal packaging differences.

Based on EU-cycle driving (numbers that we've found to be somewhat optimistic for the U.S.), the S500 Plug-In will go more than 30 km (19 miles) on a charge, in all-electric mode, Weber said, emphasizing that the S-Class is a large car and the company is being conservative with first numbers, and the future models will go farther.

Longer range anticipated for C-Class Plug-In

“The smaller cars [C-Class] from the beginning will go even longer,” said Weber. “Our target is closer to 50 km.”

Both a C-Class Plug-In Hybrid and a normal C-Class Hybrid--both of course based on the new 2015 Mercedes-Benz C-Class introduced this past week at Detroit--will be available, Weber confirmed, although the automaker won't introduce those models right away, and then it's a question of demand.

And you can expect new E-Class hybrids eventually, too. It's all part of a modular approach, from which the main components can be easily adapted to the whole MRA (Mercedes Rear-Wheel Architecture) platform—to include the C-Class, E-Class, and S-Class.

Worldwide models...but still feeling out demand

While the S500 Plug-In will go on sale first in Europe later this year, and then in the U.S. early next year, Weber emphasized that it is a world concept, as will be the C-Class models.

“It's only a question of sequence and what is really the demand behind the hybrids.” said Weber. “Because around all of our 'e-mobility,' a lot of questions are still there.”


Follow GreenCarReports on Facebook, Twitter and Google+.