The unveiling of the Cayenne hybrid follows accusations by Greenpeace that Porsche builds "climate pig" cars.

When Greenpeace demonstrators arrived at Porsche headquarters, the company said it "vehemently rejected this accusation and informed the activists that less than 12 per cent of all exhaust emissions in Germany come from passenger cars, with Porsche's share therein being less than one-tenth of 1 per cent."

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The company also defended itself saying that it plans to introduce the hybrid engine with less than nine litres fuel consumption on 100 km.

The Cayenne Hybrid will feature a full-hybrid design where the hybrid module (clutch and electric motor) is positioned between the combustion engine and the transmission. Porsche says it selected this design because the in-line configuration of the hybrid components are more compatible with the existing Cayenne platform, this system in testing is more fuel efficient, and because this configuration is a better fit for Porsche as it will provide improved acceleration and engine flexibility compared to a conventional Cayenne.

Coordinating the car's three main components – the combustion engine, the electric motor and the battery – is the Hybrid Manager, which Porsche claims is one of the most powerful technologies found in any hybrid vehicle.

Other features designed to decrease fuel consumption in the Cayenne hybrid include the power steering and vacuum pump for the brakes, as well as the air conditioning, which operate on electric power. Technical components, such as the oil pump in the Cayenne's automatic transmission, have been replaced by electrically powered units.

But Porsche assures its fans that the hybrid will still drive and feel like a Porsche, thanks to its electro-hydraulic steering – which is a first for a vehicle of its kind, the company says.

Porsche plans to introduce similar hybrid technology in a version of its Panamera four-door Gran Turismo. The Panamera will debut in 2009, with a hybrid to follow.