VOLVO started experimenting with electric power some time ago but it has now made the next step.

It has already produced prototypes with electric motors and has now added range-extending engines.

The first of these - aptly called Concept 1 - is based on a C30 Electric hatchback with a 60bhp three-cylinder engine installed under the boot floor.

The petrol engine is used primarily to drive the car's 111bhp electric motor, but the driver can also choose to make it charge the battery, thus increasing the car's operating range on electricity.

The Range Extender increases the electric car's range by up to 1,000km - on top of the 110km range provided by the car's batteries alone.

Two more similar concepts also have electric and petrol engines, and use them in tandem to produce a total amount of power.

But up to 30 miles an hour, they still run on electric power alone.

The Range Extenders make all these petrol models much more practical and can reduce emissions to as low as 50g/km - about half that of the best cars available today.

: 3yrs/ unlimited miles

: 9/10

: Toyota Prius