printable versionProgram aims to take oil from the deep fryer to diesel engines
BY MICHAEL PEÑA
Last June, Parking and Transportation Services began running the entire fleet of Marguerite buses on a blend that is 5 percent biodiesel and 95 percent petroleum diesel (B5).
Every year, Residential and Dining Enterprises generates from its kitchen facilities about 6,000 gallons of waste vegetable oil, which is currently recycled by a tallow company in San Jose and used for animal feed and soap products. But by the end of the academic year, equipment may be in place for processing the sludge into fuel that would power a number of campus vehicles with diesel engines.
David White, a health and safety specialist in the university's Environmental Health and Safety office, and Heather Perry, an environmental engineer in EH&S, presented a feasibility study to Residential and Dining Enterprises last spring that examined options for turning the oil and grease into feedstock for biodiesel—a program that would jibe well with the enterprise's "green business" certification by Santa Clara County in 2004.
Central to that distinction is the concept of environmental sustainability, which in this case means never letting the byproduct of untold pounds of French fries and crispy drumsticks ooze off campus. The key components of such a pilot program are still being examined, including who would provide labor and oversight, as well as obtaining a biodiesel processor. The study itself was presented in draft form and offers a wide array of options.
"There's so many balls in the air," Perry said. "I'm hoping by the end of the school year, we have a processor going."
Although any steps toward implementation may be months away, the popularity of biodiesel as an alternative fuel already has ramped up at Stanford. Last June, Parking and Transportation Services (P&TS) began running the entire fleet of Marguerite buses on a blend that is 5 percent biodiesel and 95 percent petroleum diesel (B5). Meanwhile, over at Jasper Ridge Biological Preserve, two tractors currently run on fuel that is 100 percent biodiesel.
Last quarter, civil and environmental engineering Professor Jeff Koseff, co-director of the Stanford Institute for the Environment, alluded to taking the oil and grease from campus kitchens to the gas tank during a presentation to the Faculty Senate on the environmental initiative. "I have this vision of walking on campus one day and seeing the Stanford Marguerite shuttle with a sign on it saying, 'Powered by Stanford Dining Services.' Wouldn't that be great?" he joked at the time.
Stanford is not alone among universities dabbling in biodiesel. According to the EH&S study, the University of Colorado-Boulder has 13 passenger buses and two recycling vehicles that run on biodiesel blends. And since November 2000, the study noted, all buses and trucks at the University of Michigan-Ann Arbor run on a B20 blend. Several large municipalities, including San Francisco and Berkeley, as well as national parks such as Yosemite and Yellowstone, utilize biodiesel as well—in some cases, using pure biodiesel.
Biodiesel can be blended with petroleum diesel in any proportion, from 1 to 100 percent. The manufacturer of the relatively new engines in the Marguerite buses protects its products under warranty as long as blends do not exceed B5, according to Kevin Mathey, Stanford's transportation programs manager. But once the engine manufacturer increases the allowable percentage, Mathey said P&TS may consider bumping up the blend it uses, too.
Most diesel engines built after 1995 do not need any engine modifications to run on biodiesel, which when compared to petroleum diesel possesses superior lubricating and detergent properties, the study said. But that ability to knock loose particles, especially in higher biodiesel blends, also has been known to clog up fuel filters, Perry noted.
Currently, P&TS gets its biodiesel off campus, from its regular gas supplier. But at some point, Perry said an on-campus processor could supplement the needs of the bus fleet, although it could never fully meet demand. In the study, one scenario looks into Residential and Dining Enterprises (R&DE) acquiring and operating a demonstration-scale processor, with a capacity of 40 gallons per batch. There could, however, still be an "array of permits and licenses" that R&DE must obtain from Santa Clara County and the state. The report also called that scenario one of the most ambitious.
Another possibility has Facilities Operations staff transporting the cooking oil to an on-campus processor based in a department other than R&DE, such as Facilities Operations, EH&S or Stanford's solid waste disposal contractor, Peninsula Sanitary Service Inc. The existing facilities and skills of the workers in those departments may be more suitable for biodiesel processing, although proper chemical-handling training and oversight would need to be ensured, the study stated.
Still another scenario envisions a partnership with an academic department on campus, such as Chemical Engineering or Civil and Environmental Engineering. The study describes this as an attractive option because of its potential to increase awareness of biodiesel use, involve students and perhaps save money through shared costs for such things as construction and equipment operation and maintenance. In fact, the Institute for the Environment already has awarded Students for a Sustainable Stanford a $2,500 grant to help start a program to convert waste oil from the dining halls into biodiesel, Perry said.
Among biodiesel's environmental benefits are that emissions of sulfur compounds are close to zero; and when compared to petroleum diesel, emissions of polycyclic aromatic hydrocarbons—many PAHs are carcinogenic—are 80 percent lower when biodiesel is used. Carbon monoxide emissions are 44 percent lower, White and Perry state in the study.
That said, across the larger spectrum of alternative fuels, experts assert that biodiesel still shares the drawback of its petrol counterpart, which is that both pollute the air. In terms of sustainability, however, supporters say biodiesel is a worthwhile option.
"If you're taking a waste product directly from campus and making it into a fuel that is used directly on campus, you're closing the loop," White said. And on a more global scale, he added, biodiesel is less taxing on the planet's resources because it forgoes the heavy mining associated with fossil fuels.
The study does not give more weight to any one option over another, but rather encourages R&DE to consider pursuing elements in each of the options. Nor does the study suggest running any university vehicles on unprocessed vegetable oil like the "Veggie Van," which acts as a rolling exhibit as it tours around the country advocating alternative fuel.
With regard to the handful of university vehicles that currently run on diesel, mostly used by Facilities Operations and EH&S, the study proposed starting them out on B20. In addition to utilizing a higher ratio of recycled oil, B20 is commonly used around the country and has shown to be a smooth transition for diesel engines that go bio.
"This was driven by Dining Services," said White, adding that the operation's executive director, Rafi Taherian, remains committed to finding a sustainable solution for waste oil. "Rafi should get credit for showing some leadership on this."