Issue date: 7/16/07 Section: News

Media Credit: Lennie Mahler

Next time you catch a ride on a campus shuttle, chances are it will be fueled by an emerging alternative fuel -- bio-diesel.

Although bio-diesel notably reduces the amount of pollutants compared with petroleum-based diesel fuel, it does not burn as clean as natural gas, which the U had previously used to power its shuttles and vans.

The school is switching to bio-diesel because natural gas engines have proven unreliable, owing to their expenses to maintain and repair, said Jake Green, a transportation planner with commuter services.

"It's a question of weighing trade-offs for the best outcome," said Craig Forster, interim director of the new campus Office of Sustainability. "(It's) a question of life cycle cost -- energy versus output."

For the past six weeks, most shuttles on campus have been running on a B-20 grade of bio-diesel fuel -- a less polluting upgrade from the previous B-5 mixture. The new grade is a mix of 80 percent diesel fuel and 20 percent vegetable oil.

Working with the state, which will supply the fuel, the U will now fuel all diesel-powered shuttles and service vehicles on campus with bio-diesel.

The decision to replace the shuttles running on natural gas was a question of cost and efficiency, not an environmental one.

"Cost effective wise…bio-diesel is cheaper to run compared to natural gas," Green said. "We have no goal (to reduce emissions) as of yet, but are continually striving to do better."

Another problem with using the more environmentally friendly natural gas is that natural gas engines can only run seven to eight hours before refueling is necessary. The diesel engines can run on a tank of gas for up to 16 hours.

Bio-diesel fuel does have drawbacks, though.

According to the Energy Information Administration, bio-diesel has a hard time performing in cold temperatures and currently delivers 2.2 percent less fuel efficiency than petroleum diesel. Also, according to Dave Rees, who manages the U's motor fleet, bio-diesel costs the same per gallon as diesel does.

The change, however, will not make bio-diesel the only alternative fuel used on campus.

Rees said the school will not completely move away from natural gas as a fuel source. Currently, the motor pool employs two hybrid Honda Civics in addition to four Civics and several vans that run exclusively on the gas. Rees has also bought several vehicles that run on ethanol corn oil and are being stored for future use when ethanol fuel is more readily accessible.

Commuter Services is experimenting with at least two vehicles that are fueled purely on used cooking oil collected from cafeterias on campus.

As a fuel, bio-diesel has drawbacks and advantages that have encountered both support and criticism about its potential as a sustainable fuel alternative.

"It's a positive step in the right direction," said Lindsay Clark, co-founder of the student group Sustainable Environments and Ecological Design. "The biggest problem with bio-diesel, however, is how it's manufactured."

Critics of bio-diesel say that it takes more oil to produce a crop into fuel than it will actually save. Clark, though she acknowledges bio-diesel's shortcomings, believes that it is a step in the right direction because it's a partially renewable energy source.

"As far as sustainable fuel for the future, we have to embrace the idea that there won't be just one fuel source any more," Clark said.

j.long@chronicle.utah.edu

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