Volvo Car Corp. announced on Monday a joint venture with Swedish energy firm Vattenfall to launch plug-in hybrid cars by 2012.

The companies have been testing plug-in technology since 2007. The new car would be powered by electricity and diesel and charge from a standard wall socket in five hours, Volvo said .

The range when driving solely on the battery will be up to 50 kilometers, Volvo said. Three quarters of European drivers drive that distance or less daily, Volvo said.

This is an important business development for us and our partnership with Vattenfall allows us to take a giant step toward offering our customers cars with an even smaller environmental footprint, Stephen Odell, President and CEO of Volvo said in a released statement. The firm is owned by American automaker Ford.

Through this cooperation we hope to be able to speed up the introduction of electric cars, Vattenfall's CEO and President Lars G Josefsson, said.

The development of the cars is being carried out and financed jointly by the companies. Volvo will manufacture the cars and Vattenfall will develop charging systems and supply the cars with electricity, the companies said.

The cost of the project was not disclosed.