Stuttgart, Germany  - German premium carmaker Porsche expects to have a petrol-electric version of its Cayenne sports utility in the showroom by 2010, the company announced in Stuttgart.

The parallel hybrid will consume less than nine litres of fuel per 100 kilometres but offer a hefty 380 horsepower from the combination of a 3.0 litre petrol engine and an electric motor turning out 52 additional horses.

Porsche said the aim was to offer a green version of the successful SUV, a genre of cars often criticised by environmentalists for their excess fuel consumption, without compromising the performance which consumers expect from the brand. Prices have not been announced so far.

The electric motor is powerful enough to drive the hybrid car alone for short distances and doubles up as a starter for the engine. The electric unit will be used mainly to provide extra power during acceleration and to redirect current from regenerative braking into onboard batteries for later use.

The stop-start automatic mechanism fitted as standard will cut the petrol engine at traffic lights to save fuel, but can also disengage the petrol motor at speed to allow coasting on downhill stretches of road.

The feature, which temporarily disconnects the engine from a new eight-speed transmission, cuts fuel consumption by reducing drag. It also harks back to a freewheel device offered on British-made Rover cars on the 1950s.

Michael Leiters, general project manager for the Cayenne Hybrid, said the petrol-electric SUV will deliver the performance of a V8 engine but display the typical lower fuel consumption of a four-cylinder engine. Similar technology is expected to find its way into the marque's upcoming Panamera four-door saloon later.

A new version of the Cayenne powered by a 3.0 litre diesel unit based on the Audi V6 motor is expected to make its debut at the Geneva car show next month which runs from March 5 to 15. (dpa)