It’s been a point of contention ever since details of the Chevrolet Volt were first revealed – is it a hybrid or is it an electric car?

In theory it seems to have all the hallmarks of a hybrid as it features both an electric motor and a conventional engine – but GM’s global director of advanced propulsion and environmental communications John Willens has other ideas.

“It’s an electric vehicle,” he said. “The electric motor drives the wheels at all times.”

Indeed the Volt has a 16KwH lithium-ion battery pack that provides a range of around 40 miles – which is perfectly sufficient for most everyday use.

However, the Volt also features a small petrol engine which acts as a generator recharging the battery – this means that Volt drivers won’t be stranded if they travel for more than 40 miles. As such GM officially labels the concept E-REV – an extended-range electric vehicle.

The Volt is understandably attracting plenty of attention at the Paris Motor Show and it has made many advances since its initial unveiling in Detroit in 2007. Among them is a more rounded shape, which boosts aerodynamics adding miles to the range.

While the Volt is scheduled to go on sale in the USA in 2010, Europeans will have to wait a little longer – but could receive the E-REV concept on other vehicles, including the next-generation Zafira, which will use the same platform as the Volt.

“The system can drop in to other cars in the GM range,” said Willens.

It is also possible that future models may see the petrol generator replaced by a fuel cell – that is when the technology is available at a more affordable price.