Badged a GLC350e, the plug-in hybrid SUV makes its debut on Tuesday at the Frankfurt International Motor Show and should be at dealerships within the first half of 2020. Outside the United States, Mercedes will also add a plug-in hybrid version of the GLE with a diesel engine for an extra efficiency kick. We’ll also receive a plug-in hybrid GLE, though with a gas engine. The powertrain of the GLC350e is comprised of a 2.0-liter inline-4 and an electric motor-generator integrated with a 9-speed automatic transmission. System output is 315 horsepower and 516 pound-feet of torque, or enough for 0-60 mph acceleration in about 5.6 seconds. Drive is to all four wheels as standard. The electric motor-generator, which also serves as the engine’s starter, is able to recover energy under braking and store this in a 13.5-kilowatt-hour lithium-ion battery. Mercedes quotes a range of 30 miles on a full charge of the battery, though this is measured on the lenient NEDC cycle. An EPA-rated electric range will likely come in below 20 miles. For buyers opting for the GLC’s Multimedia Package, the GLC350e plug-in hybrid powertrain benefits from route-based operation, where fact...