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Greasing the Skids
November/December 2007
by Melinda Tuhus
In 2005, a Yale
undergrad made so bold as to fill his truck’s gas tank with 100 percent
bio-diesel fuel, which he'd rendered himself from dining hall grease. The truck
didn’t explode. The engine didn’t sputter. And thus began Yale’s romance with
bio-diesel.
Giovanni Zinn '05
doesn’t try to take credit for the fact that Yale’s 19 shuttle buses are now
operating on 20 percent soybean-derived bio-diesel fuel. But he thinks his truck
served as a catalyst. His senior project, aided by a $25,000 grant from the
Yale Green Fund, was building a processor to recycle the waste vegetable oil
from Yale’s dining halls.
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Manufacturers won’t warranty
an engine that uses more than 20% percent bio-diesel. |
Zinn worked with David
Johnson, a technical specialist in chemistry. They separated glycerin from the
grease to make yellow diesel, which can fuel cars, trucks, or buses. Students
from Yale Recycling then began collecting fry grease from dining halls. The oil
was strained before processing (to filter out the occasional french fry), and
soon, Zinn’s 100 percent dining-hall bio-diesel was powering the furnaces at a
Yale observatory.
Yale’s shuttle buses
are run by the New Haven Bus Service, on contract. Company president Dan Miley
says he learned of the yellow diesel experiment through Yale’s Office of
Traffic and Parking, and after consulting Johnson, he decided it was safe to
start using some yellow diesel in his fleet. (During commencement 2006, one bus
shuttled students and their parents around campus on 100 percent bio-diesel. It
ran flawlessly.)
That home-grown
bio-fuel is no more: Zinn says his processor was shut down in the fall of 2006
because the administration needed the space for another use. But the use of 20
percent bio-fuel in the shuttles' fuel mix continues.
Will Yale ever go
beyond 20 percent? Not yet, says Holly Parker, Yale’s new director of
sustainable transportation systems, because engine manufacturers won’t warranty
an engine that uses a higher percentage. But “once the engine manufacturers and
regulatory authorities see that 20 percent bio-diesel is working very well,”
she says, “I think there’ll be more acceptance of using a higher proportion in
the mix.” And Yale may yet see the day of the all-bio fleet.”  |