A year-long test of biodiesel in city buses in St. Louis, MO has shown that the green fuel is comparable in fuel economy to the cleanest version its petroleum counterpart, while being much more reliable with fewer maintenance issues.

This story posted on CanadianDriver.com says the National Renewable Energy Laboratory (NREL) study showed B20 biodiesel was within two percent of ultra-low sulfur diesel (ULSD) in fuel economy:

The evaluation was undertaken on buses in the St. Louis, Missouri Metro fleet and was conducted by NREL and the National Biodiesel Board. The study is the first B20 in-fleet study using buses equipped with EGR valves, and the first to compare B20 to ULSD. It involved 15 40-foot model-year 2002 transit buses with Cummins engines; eight operated exclusively on B20 and seven on petroleum USLD. The groups operated from different depots at St. Louis Metro, but the routes were matched for duty cycle parity.

Average fuel economy over the 12-month period for the ULSD buses was 3.58 mpg US (65.7 L/100 km), while average economy for the B20 buses was 3.52 mpg US (66.8 L/100 km).

The study also found that the biodiesel-fueled buses went longer between road calls (2,375 miles for the ULSD and 2,627 miles for the B20 groups)… an indication of biodiesel’s reliability… and the biodiesel fuel systems and engines went longer between road calls: 8,211 for B20 and 6,924 for ULSD.