2004 Audi A2H2 Concept

This daring goal was set by Volkswagen Auto Group for a series of small cars including the VW Lupo and Seat Arosa (neither of

After the A2 3L the somewhat odd tandem Messerschmitt KR200-inspired 1L concept was born. (Photo: Volkswagen Canada)

which are sold in North America). Audi's A2 3L was the highlight of the group, featuring automatic engine shutoff at idle to prevent unnecessary fuel waste, similar to that used in hybrid-electric cars such as the Toyota Prius, Honda Civic Hybrid and Ford Escape Hybrid.

Since that time, Audi has swooped under the radar with its green-energy program. Volkswagen continued with the somewhat odd tandem Messerschmitt KR200-inspired 1L concept and the recently introduced a Golf diesel-electric hybrid concept, but Audi had yet to display anything, until this year's Michelin Bibendum

Unveiled in Shanghai, the A2H2 concept is Audi and VAG's first publicly-displayed hydrogen fuel cell concept car. (Photo: Volkswagen Canada)

Challenge, the world's largest competition for sustainable drive and energy concepts.

At the event in Shanghai, the innovative German firm returned to the scene with the A2H2 concept, Audi and VAG's first publicly-displayed hydrogen fuel cell concept car.

In place of the standard gasoline or diesel internal combustion engine is a fuel cell propulsion unit linked to a storage battery system. The Ballard-designed system is completely different than the "H2 ICE" engine format, such as those featured in the BMW H2R and Hummer H2H.