Our spy photographers have snapped pictures of the next-generation Porsche Panamera in plug-in hybrid form. Both the prototypes spotted by our photographers have filler caps on both rear flanks, indicating that the cars seen here are plug-in hybrids. It's not known at this stage whether the plug-in hybrid drivetrain in the new car will differ significantly from the current model's. 
In the current-generation Panamera, the S E-Hybrid has a total output of 306kW of power and 590Nm of torque. To achieve these figures, the S E-Hybrid utilises a 245kW/440Nm 3.0-litre supercharged V6 petrol engine, a 70kW/310Nm electric motor and an eight-speed auto. Overall it drinks 3.1L/100km and is capable of up to 36km of pure electric motoring.
In EV mode, the current-gen Panamera is able to hit a top speed of 135km/h. With both motors running, the current car reel off the 0-100km/h standard in 5.5 seconds. As in the current range, the Panamera plug-in hybrid will be sold alongside other drivetrain options, including V6 and V8 petrol motors, and V6 turbo-diesels. 
The new Panamera will be the first model to utilise the Volkswagen Group's new MSB component matrix for rear- and all-wheel drive vehicles. Thanks to the use of high-strength steel and lightweight materials, such as aluminium and magnesium, the next-gen Panamera should be lighter, faster and more efficient.
Last year, Michael Mauer, Porsche's design chief, told Car Advice that new Panamera "will look better" and will feature a faster roofline, with some headroom sacrificed on the altar of improved looks. 
The new car, as borne out by these and earlier spy pictures, does indeed feature a more svelte and less bulbous look, especially at the rear. It's expected that the new Panamera will debut towards the end of 2016 and go on sale the following year.