New Haven Independent

New Haven Bus Service contracts with Yale to run its shuttle service. About 18 months ago, said company President Dan Miley (pictured), Yale contacted him and “wanted to be pro-active” in cleaning up vehicle pollution. So he agreed to run his buses on ultra-low sulfur diesel, which cuts sulfur pollution from 500 parts per million to 15. He said it costs him 20 percent more, but he’s willing to do it because of his longstanding relationship with Yale.

Then Miley installed DOCs — diesel oxygenating catalytic converters — which reduced pollution further.

“Six months ago, we wondered what else we could do, and we added 20 percent commercially developed soybean oil [B-20],” Miley said. “We wanted to make sure it didn’t affect dependability because we are part of security — our buses run 24 hours a day, seven days a week.” Miley said he found, if anything, the soybean/diesel blend makes the engines run even smoother.

Then at the end of last semester he was contacted by Yale’s chemistry department, where students had been working on a so-called yellow biodiesel project, converting cooking oil into biodiesel.

The project originated with a student who wanted to run his car on vegetable oil. He contacted Professor David Johnson, a research scientist at Yale. Through a simple process they separated the glycerin — a harmless byproduct — from the biofuel. “By removing the glycerin from vegetable oil,” Johnson said, “we essentially reduce its flashpoint from 600 degrees to 300 degrees, which allows us to use it as a heating oil. Any car, truck or bus will run on it with minimal modifications.”

Yale’s recycling coordinator C.J. May said, “My students began collecting fry grease from dining halls — Yale generates 2,500 gallons of fry grease a year. Sometimes people leave French fries in it and it’s kind of gross.” The oil is strained before being processed.

Miley said he had experimented with increasing the percentage of biodiesel in Bus 13. As graduation approached, he wondered, “Why don’t we push the envelope here? It ran good at 30 percent, no notice of any problems at 40 percent, and lo and behold, we started pushing it to the very end where we’re running this bus at 100 percent vegetable oil right now, without any major modifications.” Bus 13 was pressed into service to shuttle graduates and their families around campus at commencement on May 22.

Since it runs on used oil from Yale’s dining halls, and since the dining halls are shut down for the summer, the bus will be running on all-biodiesel just until the end of this week. But Miley expects it will be power up on the same fuel once school starts again in the fall.

“It’s not so much that we’re going to run the whole fleet on the dining hall vegetable oil,” he said, “but it certainly is a great seedbed for the students who are involved in this project to bring this as a springboard, to what’s next, what else can we do?”

Don Relihan, director of support services for Yale, said the university took the step to clean up the bus fleet “because it’s looking to reduce greenhouse gas emissions and become a more sustainable campus. Going to B-20 is a step in that direction. I’m not sure if there’d be enough of the yellow diesel to put in many more buses, but we’d probably go to a higher percentage [than 20].” He adds that the two furnaces at the Yale observatory are powered by 100 percent veggie oil [B-100].

So, my trip down Whitney Avenue to Temple Street to College Street to Phelps Gate across from the Green was uneventful — no exotic aromas, no lurching or bucking from an engine that wondered what in the world was in the gas tank. Just like in airplane travel, I guess uneventful is the best way to go.