Contrary to published reports, no plug-in Porsches were sold in the U.S. last month.

Whether the first one is handed over late this month or early next month--we'll know by Friday, January 3--the company is taking an unusual step with its 2014 Porsche Panamera S E-Hybrid.

The German prestige maker is eliminating its Panamera Hybrid, a model only on sale in the U.S. for 2012 and 2013, and replacing it entirely with the plug-in hybrid version.

2014 Porsche Panamera S E-Hybrid

2014 Porsche Panamera S E-Hybrid

It will continue to sell the Porsche Cayenne S Hybrid, a conventional hybrid version of its luxury sport-utility vehicle, for 2014.

But the Panamera S Hybrid, which sold less than 700 units during its two years on the U.S. market, is on the way out, with fewer than a dozen left at Porsche dealers nationwide.

MORE: 2014 Porsche Panamera S E-Hybrid: First Drive

The EPA hasn't yet posted efficiency ratings for the plug-in hybrid Panamera, but Porsche's product communications manager Nick Twork said that the company expected an EPA rating of 15 miles of electric range, and 46 MPGe in electric mode.

MPGe, or "miles per gallon equivalent," is a measure of how far a car can travel electrically on the amount of energy contained in 1 gallon of gasoline.

Porsche logo

Porsche logo

While 46 MPGe is less than half the 119-MPGe rating of the 2014 Chevrolet Spark EV minicar, it's worth noting that the best fuel-efficiency rating for a gasoline Panamera is 22 mpg combined for the base version with a 300-horsepower 3.6-liter V-6 and a seven-speed DSG automatic dual-clutch transmission.

The plug-in hybrid Panamera is powered by a supercharged 3.0-liter V-6 and a 70-kilowatt (95-hp) electric motor sandwiched between the engine and an eight-speed automatic transmission, which Porsche says works more fluidly with the electric motor than the dual-clutch transmission used on other Panameras.

The motor is powered by a 9.4-kilowatt-hour lithium-ion battery pack, which replaces the conventional hybrid's 1.7-kWh nickel-metal-hydride pack at a weight penalty of about 250 pounds.

MORE: 2011 Porsche Cayenne S Hybrid: Drive Review

That brings total curb weight of the plug-in hybrid Panamera to 4,620 pounds (against 3,880 for a base Panamera V-6 model).

Porsche quotes a total powertrain output of 416 horsepower--or slightly more than the conventional V-8 Panamera S model--and a 0-to-60-mph acceleration time of 5.2 seconds.

The 2014 Porsche Panamera S E-Hybrid starts at $99,000, and will be available within weeks at selected Porsche dealers in certain states.

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