WASTE NOT WANT NOT. Startups like San Diego-based New Leaf Biofuel collect used oil from foodservice establishments and convert it into biodiesel, turning waste into an environmentally friendly fuel.

Ethanol gets a lot of press, but it's hardly the only plant-based alternative to petroleum-based fuels.

One that has been much less publicized, but may in some ways actually be a better choice, is biodiesel technology. Biodiesel uses vegetable—indeed, any organic— oil to fuel conventional, but modified, diesel engines.

Biodiesel is especially pertinent for foodservice operators because it potentially creates a market for waste oil, something that currently poses an annoying—and often expensive—disposal problem.

And, since using oil to cook food does not affect its chemical profile as a fuel, foodservice programs with large volumes of used oil are potentially natural partners for biodiesel programs.

Those programs get a ready, inexpensive (and in many cases, free) supply of fuel while the foodservice operation saves the cost and annoyance of getting rid of the stuff. Both parties can feel good about doing something for the environment, since biofuel is not only "sustainable" and domestically produced, but emits 75 percent less greenhouse gas than petroleum fuels do, with no sulfur emissions. And, because it is biodegradeable, spills pose no environmental hazards. In addition, it is fuel-efficient and produces zippy vehicle performance.

Currently, biodiesel remains one of those "alternative fuel" technologies that are much talked about by politicians eager to get on the good side of the "green" movement. But in practice, it remains largely the province of experimental programs on college campuses and of scattered entrepreneurial startups seeking to get a jump on what may one day be a mainstream business.

In fact, though, biodiesel is not a pie-in-the-sky technology. Rudolph Diesel originally designed his engine to run on vegetable oils back in the 1890s as a homegrown way for farmers to power their tractors. Today, it is perfectly possible to modify a standard diesel engine to run on vegetable oil, something that a growing number of environmental pioneers (including music superstar Willie Nelson) have already done.

The primary practical difficulty with using vegetable oil as a fuel is its viscosity. Unless heated, it is too thick to flow freely, so engines need a warmer that is activated before the vehicle starts up in order to liquify the fuel sufficiently. (Vegetable oil can also be mixed with a ratio of standard diesel fuel to keep it properly liquified, with the ratio depending on the expected ambient temperature.)

Alternately, a practical biodiesel fuel can be refined by mixing waste oil with ethanol or methanol. However, because the latter alcohols are highly volatile and flammable, such production must be regulated by the government.

Despite the obstacles, some tentative steps toward what seems a logical sustainability initiative have been taking place around the country. On college campuses, the technology has caught the eye of students and professors looking "green" solutions. The government has also been active and EPA has funded a number of student-led research programs exploring biodiesel at Oregon State University, Middlebury College, Oberlin College and Penn State.

Meanwhile, at the Massachusetts Institute of Technology, a student-led initiative called Biodiesel@MIT wants to establish an on-campus filling station for diesel-powered campus vehicles that would use the waste fry oil from campus eateries. The initiative would potentially save the university some $12,000 in fuel costs and $4,000 in fry oil disposal costs annually, according to an MIT news release.

At the University of Illinois at Urbana, the Biodiesel Initiative is looking to produce up to 400 gallons of biodiesel fuel from waste vegetable oil from dining halls. At Stanford University, FSD Rafi Taherian has been pushing for a program to make onsite use of the 7,000 gallons of waste oil the dining services department produces each year.

Not only universities are interested. The School of Science & Technology at San Diego High School is working with a local biodiesel processing startup called New Leaf Biofuel to build a biodiesel processor that can convert the used cooking oil from the district's cafeterias into fuel for its vehicles.

Other fuel uses are also possible. One Reno casino, the El Dorado, has even adapted its water heater to burn the waste oil from its kitchen.