The first wave of electric cars and plug-in hybrids has been largely centered on smaller vehicles, mostly from mass-market brands (Tesla excepted).

Four years later, German luxury makers are entering the fray--and the plug-in cars and utility vehicles they sell will markedly expand the offerings on the market.

DON'T MISS: Mercedes-Benz S-Class Plug-In On Sale Early 2015, C-Class Hybrid Later

We've now been able to tease out the company's schedule for its first three plug-in hybrid vehicles in the U.S.

We'd already known about two of them--the plug-in hybrid S-Class and C-Class sedans--but now we've learend there will be an ML plug-in hybrid crossover utility vehicle too.

2015 Mercedes-Benz S500 Plug-In Hybrid

2015 Mercedes-Benz S500 Plug-In Hybrid

Plug-in for burgermeisters

First to arrive will be the S-Class Plug-In Hybrid, the largest and most expensive plug-in hybrid of three the company will launch over the next 18 months.

It will show up at the first U.S. dealerships--likely to be in California and perhaps a few other states--less than a year from now, sometime during Spring 2015.

MORE: Frankfurt Auto Show: Plug-In Hybrid Mercedes S-Class Concept (Sep 2009)

The plug-in version of the ultimate Mercedes sedan, the car known to generations of successful German businessmen as the pinnacle of achievement, has actually been around as a concept for several years.

2015 Mercedes-Benz S500 Plug-In Hybrid

2015 Mercedes-Benz S500 Plug-In Hybrid

It was first shown as the "Vision S500" concept at the Frankfurt Motor Show in the fall of 2009, and announced as part of the S-Class lineup when the most recent generation was unveiled for the 2014 model year.

The plug-in hybrid S-Class is powered by a 328-horsepower, turbocharged 3.0-liter V-6 gasoline engine and an 80-kW (107-hp) electric motor sandwiched between the engine and an adapted version of the company's eight-speed automatic transmission.

The company quotes 0-to-60-mph acceleration of about 5.5 seconds. Although space for the rear-mounted lithium-ion battery pack was designed into the bodyshell of the new generation S-Class, photos appear to show some reduction in trunk space.

2015 Mercedes-Benz C-Class live photos, 2014 Detroit Auto Show preview

2015 Mercedes-Benz C-Class live photos, 2014 Detroit Auto Show preview

Europe, then U.S.

The S-Class Plug-In Hybrid should go on sale in Europe this fall, and arrive in the U.S. next spring. It will compete most directly against the Porsche Panamera S E-Hybrid, as well as hypothetically against the Tesla Model S all-electric luxury sedan.

Second will come a plug-in hybrid model of the C-Class, part of the new generation of that vehicle launched for the 2015 model year at January's Detroit Auto Show.

Electric range of the S-Class plug-in hybrid is likely to be more than 30 km (19 miles) on the European test cycle--U.S. numbers will be lower--but the lighter C-Class that follows, presumably using the same powertrain, should earn a higher range rating.

The plug-in C-Class will arrive in the fall of 2015, undoubtedly as a 2016 model.

ALSO SEE: BMW X5 Plug-In Hybrid Prototype: We Drive Future Electric SUV

Adding utility

Third, Mercedes will also launch a plug-in hybrid version of its ML-Class crossover utility vehicle at roughly the same time as the C-Class.

2014 Mercedes-Benz M Class RWD 4-door ML350 Angular Front Exterior View

2014 Mercedes-Benz M Class RWD 4-door ML350 Angular Front Exterior View

The ML-Class is due for a mid-cycle refresh for 2016, and small numbers of a plug-in hybrid version will be offered as part of the lineup.

That vehicle will go head-to-head with plug-in hybrids from BMW, Mitsubishi, Volvo, and possibly Range Rover as well.

The low-volume Toyota RAV4 EV and upcoming Tesla Model X aside, no crossovers that plug in are on sale--despite the segment's huge popularity in the U.S.

Officially, “Mercedes-Benz is considering an ML-based Plug-In Hybrid," said Christian Bokich, product and technology communications manager, "but hasn’t yet made an official announcement.”

Beyond the trio of plug-in hybrids next year, the most intriguing notion to emerge from Mercedes is that of an all-electric version of the S-Class sedan.

MORE: Mercedes S-Class Electric Car Could Follow Plug-In Hybrid

It would compete head-to-head with the Tesla Model S, although its steel body would be far heavier, meaning it would likely need a battery pack well over 100 kilowatt-hours to match the Tesla on range.

Such a vehicle seems more likely to come as part of the next generation of S-Class--around 2020--but in the fast-moving electric-car world, perhaps anything is possible.

_______________________________________________

Follow GreenCarReports on Facebook, Twitter, and Google+.