With the quest to increase the capacity of battery powered vehicles, a group of enthusiasts from Australia, Germany, and Switzerland have set off in their battery powered vehicles on what's being billed as the "longest and greenest" round-the-world drive to promote emissions-free transport and November's world climate conference.

The UN-supported "Zero Race" has been organized by a Swiss Louis Palmer, who made headlines with his 18-month pioneering world tour in a solar-powered "taxi" two years ago, picking up celebrities on the way.

Palmer said: "With this race we want to show that seven billion people on this planet need renewable energy and clean mobility. Petrol is running out and the climate crisis is coming, and we are all running against time."

A Korean vehicle failed to reach the start line at the United Nations in Geneva in time after it broke down with "a minor battery problem" about 60km up the road, Palmer said, but would join the other three teams later in the day.

The Zero Race team is set to stop off at the World Climate Conference in Cancun, Mexico, after touring through Europe, Russia, China, Canada, and the United States before heading back to Geneva in January 2011.

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Each plug-in electric vehicle can travel at least 250km on a charge, with 80 days of driving time ahead of them. They are obliged to consume no more electricity than each team has generated or purchased from clean energy sources such as wind, solar, and hydroelectric power.

Australian team Trev, run by 57-year-old Jason Jones and his 24-year-old son Nick, said the trip through 16 countries would cost them about 400 Australian dollars in fuel.

Standing next to their plastic-bodied two-seat three wheeler, Jones senior explained: "We've already bought the power and put it back in the grid. We thought it just a great way to show what this car is capable of. The future of automotive transport is not one-and-a-half ton gas guzzlers."

The vehicles, which also include a Vectrix scooter from Germany and a Swiss Zerotracer two wheeler with a claimed top speed of 240km/h, will be followed by Palmer in a repair van with a trailer.

Palmer said emissions from the the van as well as ship crossings across the Pacific and Atlantic oceans would be carbon offset.