Porsche has been testing what appears to be a 911 hybrid from these latest spy pictures.
On top of the bonnet sits a matt black box, suggesting this is where the car maker would fit the electric motor.
This may limit the hybrid to just the Carrera 2 models as the space is limited in the front of the four-wheel drive model.
The car was extremely quiet when it was pulling away, our spy photographer told us, but when spotted accelerated at considerable speed.
The bonnet bulge has been adorned with a lightning bolt sticker and there is what appears to be a “no pacemaker” sign on the window.
Theoretically the 911 could be the first to do without a flat six as a lower-powered, possibly four cylinder, engine would be needed if it was boosted by an electric motor.
A hybrid 911 would be a logical step to help Porsche reduce its overall emissions because it is such a big seller.
Although there’s no concrete news on the design of the hybrid system, the likely solution will see the Carrera 4’s front suspension system re-designed, replacing the front differential with some kind of the electric motor.
This would mean the rear wheels are powered by the rear-mounted engine and the front wheels by an electric motor and battery power.
This would allow the 911 Hybrid to be driven in pure electric mode – though it would be front drive – or in petrol-only mode via the rear wheels.
Both forms of propulsion could be used together for improved acceleration and the electric front-drive could also be used intermittently to improve handling and grip.
It’s also possible that a four-cylinder flat-four turbocharged engine could be used in a future 911 hybrid, though that would be a controversial move.
Porsche is planning hybrid versions of both Panamera and Cayenne and, although the flat six in the 911 is a very different engine, the technology does exist.
A hybrid 911 would have formidable fuel economy for such a sporting car. The standard 997 currently manages almost 30mpg on the combined cycle and with the aid of an electric motor this could be boosted to 50mph.
The 911 hybrid is still in the early stages of development and is not likely to appear before 2011.