Click here for a photo gallery of the 918 Spyder.

The 918 Spyder prototype is the German carmaker’s offering to the growing market for hybrid cars that combine an internal combustion engine with electric propulsion, dramatically slashing the amount of greenhouse gasses the car emits.

Porsche unveiled its creation at the 2010 Geneva Motor Show. It claims the car has a top speed of 320 km/h but uses just three litres of fuel for every 100 kilometres – equivalent to 94 miles per imperial gallon.

“We are a sports car manufacturer and that means it’s about driving fast – but at the same time about cutting pollution and conserving natural resources,” Porsche chief Michael Macht said according to the website of news magazine Der Spiegel.

Critically, the Spyder emits an average of just 70 grammes of carbon dioxide, the firm claims. According to Britain’s Department for Transport, the third-generation Toyota Prius – the best-known hybrid car – emits 89 g/km.

Many conventional supercars, including models made by Ferrari and Lamborghini, emit between 400g and 500g of carbon per kilometre.

The Porsche prototype makes it around the legendary 22.8 kilometre Nürburgring race track south of Cologne in less than seven-and-a-half minutes, Macht boasted.

Driving legend and Porsche representative Walter Röhrl concurred, saying: “This car goes even faster than the last super sports car from Porsche, the Carrera GT.”

Martin Winterkorn, Chairman of the Board of Management of Volkswagen, Porsche’s parent company, added: “Porsche is showing the future.”

The open two-seater has a high-performace V8 engine with more than 500 brake horse power and a maximum engine speed of 9,200 rpm as well as electric motors on the front and rear axle.

The electric motors are powered by a fluid-cooled lithium-ion battery than can be recharged by plugging it into a normal power point.

Porsche also used the Geneva show to release two other hybrids: a Cayenne S Hybrid SUV and a 911 GT3 R Hybrid racing car.