Porsche already offers a hybrid variant of its sports SUV, the Cayenne, but it's more about stemming the car's massive thirst than it is a truly green vehicle.

A plug-in hybrid version coinciding with a mid-cycle update around 2014 could offer a much more gas-sipping option, however.

According to Motor Trend (via MotorAuthority), the Cayenne e-Hybrid would feature an upgraded electric motor over the current Cayenne Hybrid, offering 95 to 100 horsepower.

This would allow it to run on electric power alone at much more useful speeds than the regular Cayenne Hybrid. The system is based on the drivetrain previewed in the Porsche Panamera Sport Turismo concept at September's Paris Auto Show.

Matched with the current 333-horsepower supercharged V-6, combined output is expected to be a useful 420-hp.

A lithium-ion battery of 10 kWh or more is expected to provide around 15 miles of all-electric range. That gives it a little more electric range than a plug-in Prius, and a little less than the Ford Fusion Energi--but could result in significant gas savings for city dwellers.

Combined economy could be as high as 67 mpg--though as always, figures like that have to be taken with a pinch of salt.

Still, any improvement over the 2012 Porsche Cayenne S Hybrid's combined economy of 21 mpg is welcome--and Porsche buyers will no doubt appreciate the performance increase too.

The e-Hybrid is expected to debut in 2014, as a 2015 model-year vehicle.


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