Synthetic diesel made by RenTech, Inc. is just as efficient as regular diesel fuel but makes less organic emissions. The fuel is produced from organic compounds and green waste.

Two Audi A3 TDI models have made a 1,000 mile (1,609 km) journey down almost the entirety of the California coast powered by a new synthetic diesel fuel.

The two A3 TDI's were running on RenDiesel, a synthetic fuel produced by RenTech, Inc. The fuel is produced at a RenTech facility in Rialto, California and is made from organic compounds and green waste that are usually dumped in landfills. The synthetic diesel produces less volatile organic compound (VOC) emissions than regular diesel fuel or ethanol.

The project was a joint one between Audi of American, RenTech and Green Car Journal, a U.S. environmental publication. The trip took the two A3's from Eureka in Northern California all the way to San Diego it's southern-most city.

The trip also proved the mileage rating of the A3 TDI which comes in at 42 mpg (5.6 liters/100 km) under the U.S.'s EPA cycle. One averaged 43 mpg while the other car did 39.7 mpg.

"Operating on advanced, clean burning fuels like synthetic RenDiesel simply makes the diesel equation even more compelling," said Ron Cogan, who edits and serves as editor and publisher of Green Car Journal.

Last December, the Audi A3 TDI was the winner of the 2010 Green Car of the Year - an award issued by Green Car Journal.

Audi A3 TDI does 1,000 miles on synthetic diesel