Studies show that biodiesel outperforms gasoline, ethanol, and conventional diesel in reducing climate-altering carbon dioxide emissions and in overall fuel-efficiency (see sidebars below).

Using 100-percent biodiesel (B100) eliminates all of the sulfur emissions associated with conventional diesel, cuts emissions of carbon monoxide and smog-producing particulate matter almost in half, and reduces hydrocarbon emissions by between 75 and 90 percent. Perhaps most significantly, using B100 reduces the emissions of carbon dioxide—the main greenhouse gas causing global warming—by more than 75 percent. Even using a blended biodiesel fuel like B20 (a 20-percent biodiesel/80-percent petrodiesel blend offered at most biodiesel fueling stations) still reduces carbon dioxide emissions by 15 percent, according to the Department of Energy.

Besides lowering emissions at the point of use, biodiesel fuel—made from corn, soy, or other plant matter—had a past life absorbing carbon dioxide while it was growing as a crop in the field. With its past carbon dioxide absorptions balancing its later carbon dioxide emissions, biodiesel results in an overall life-cycle lowering of carbon dioxide emissions over both conventional diesel and gasoline. The industrial processes used to produce biodiesel are cleaner than conventional diesel processes, reducing emissions associated with the life cycle of the fuel by more than 80 percent.

As a cleaner burning fuel, biodiesel is better for a car’s engine than conventional diesel, providing greater lubrication and leaving fewer particulate deposits behind. Biodiesel’s high ignition point (350°F vs. –43°F for gasoline) makes it a safer fuel as well. Biodiesel is biodegradable and considered nontoxic by the Environmental Protection Agency. All diesel vehicles have 20- to 30-percent higher fuel economies than comparable gasoline vehicles.

Biodiesel also frees car-drivers from reliance on dwindling fossil fuel resources and the world politics associated with obtaining those resources. It also keeps fuel dollars in the US. Biodiesel is more accessible than ever, with the number of public fueling stations in the United States rising from zero in 1997 to 750 today. To find a biodiesel fueling station or local biodiesel supplier near you, visit the National Biodiesel Board’s Web site. —Andrew Korfhage -Coopamerica.org

Biodiesel and the Future

In the long term, renewable energy experts differ on the upper limit of biodiesel’s possibilities as an industry, should biodiesel become wildly successful, adopted as America’s primary choice for fuel.

With the country already consuming more than 40 billion gallons of diesel fuel every year, a massive shift to biodiesel would make impossible demands on our available agricultural land. Cornell ecology professor David Pimintel explained in a 2005 study how he had studied large-scale bio-fuel production based on corn, switchgrass, wood biomass, soy, and sunflowers, and found each to be unsustainable. Others argue that even if such land-use was a possibility, the resulting agricultural shift toward fuel farming would trigger unintended consequences, such as spikes in the price of food crops. For example, in Europe, demand for biodiesel has triggered increasing imports of Indonesian palm oil, which in turn has accelerated massive deforestation in Indonesia, as farmers clear forests for palm plantations.

Meanwhile,University of New Hampshire physicist Michael Briggs explained in a 2004 paper how aquatic farms could be used to grow resources for biodiesel production, taking pressure off land intensive crops like corn and soy. With high oil content, fast growth rates, and less land-use, some aquatic crops like algae make practical sense as future sources for biodiesel fuel, as demand grows. A 1998 report prepared for President Clinton by the National Renewable Energy Laboratory reached a similar conclusion, but with the caveat that biodiesel production from aquatic resources would “only be competitive if petroleum diesel cost more than $2 a gallon.”

How do the fuel compare?

In terms of efficient energy production and overall carbon dioxide emissions, biodiesel trumps not only conventional diesel, but also gasoline and gasoline’s bio-fuel substitute, ethanol.

For example, according to a study by the Minnesota Department of Agriculture, biodiesel produces 3.2 units of energy for every unit of fossil-fuel-energy consumed in its production. Ethanol yields a lower 1.34 units of energy, while gasoline and conventional diesel represent a negative yield. (The influx of solar energy into the organic resources—corn, soy, etc.—that will eventually become ethanol or biodiesel accounts for their positive energy yield.)