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Evaluating Natural Gas in Transit Buses and Shuttles

NREL is proud of the natural gas fleet studies its Fleet Test & Evaluation (FT&E) Team has recently completed. The studies offer guidance on how agencies can successfully implement natural gas vehicles into their organizations.

Natural Gas in Transit Fleets: A Review of the Transit Experience (PDF 685 KB) is an extensive technical paper that features the survey results of 43 American transit agencies that have compressed or liquefied natural gas buses in their fleets. Download Adobe Reader. Often motivated by air quality concerns, use of natural gas also contributes to better national and local energy security.

Sponsored by DOE's Advanced Vehicle Testing Activity, the FT&E team launched the project in February 2001 with the help of Denver's RP Publishing, which developed the survey and conducted interviews with more than 60 transit managers. The resulting 33-page document educates transit fleet managers interested in trying natural gas buses, and offers success stories; helpful suggestions for adding natural gas buses and infrastructure; and information on costs, maintenance, operational differences.

Photo of the Super Shuttle van.

The team also completed an evaluation of Denver's SuperShuttle fleet of 13 1999 Ford E-350 passenger vans. The study, featured in SuperShuttle CNG Fleet Study Summary (PDF 386 KB), a six-page fact sheet, focuses on five dedicated compressed natural gas (CNG) vans, five bi-fuel CNG/gasoline vans, and three conventional gasoline vans, which shuttled passengers from Boulder, Colorado, to Denver International Airport (DIA), about 45 miles away. Download Adobe Reader. The vans typically accumulate about 60,000 miles per year.

The 18-month study features data on the vans' fuel use, maintenance, emissions, and performance. The evaluation team found that:

  • The average fuel economies for the gasoline and bi-fuel vans were nearly the same, at 11.7 and 11.6 mpg respectively. The dedicated CNG vans had a slightly lower average fuel economy of 10.6 mpg.
  • The gasoline vans averaged 5,493 miles per month, bi-fuel vans averaged 5,161 miles per month, and dedicated CNG vans averaged 3,692 miles per month.
  • The average use of CNG in the bi-fuel vehicles was 28.3% by volume.

For more information about our fleet evaluations, which aim to help fleet managers and general consumers make educated decisions about purchasing alternative fuel vehicles, visit the Advanced Vehicle Test Activity Web site.

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