Biodiesel: The Burning Question

If you’re thinking that a brave new world of agriculturally derived, clean-burning biodiesel fuel is going to wean us off petroleum, you’d better think again. Not even the National Biodiesel Board (NBB) thinks that. In the near future, NBB believes (based on Department of Energy estimates) that biodiesel could at best supply 10 percent of America’s fuel needs. It will complement, not replace, fossil fuels.

This isn’t the only soybean-based biodiesel bus in Nebraska: State school© Nebraska Soybean Board/NREL

The problem is that devoting huge tracts of farmland to soy or canola crops for biodiesel production is neither economically feasible nor physically possible, given their low per-acre yields. “At this point there aren’t any plans to grow crops for biodiesel,” says NBB spokesperson Jenna Higgins. “We don’t theorize on how much land it would take because it isn’t very realistic.”

An analysis in the British Guardian concluded that to convert all road transportation in the United Kingdom (cars, trucks and buses) to canola-derived biodiesel would require 64 million acres of land, when there are only 14 million arable acres in all of Great Britain.

“We don’t believe that biodiesel alone is the silver-bullet solution to our fuel needs, though we do think the number will go higher than 10 percent because biodiesel can be made from any fat or vegetable oil,” says Higgins. NBB says the economics of biodiesel work best when dealing with soybean oil as a surplus commodity left over when soy meal is produced, usually for animal feed. It’s obviously also cost effective (as well as overwhelmingly positive environmentally) when the raw material is free: used cooking oil from restaurants that would otherwise have to pay to have it removed and rendered.

None of this is to denigrate the burgeoning biodiesel movement, which is likely to climb to 75 million gallons in 2005 (from 25 million gallons in 2004). Biodiesel can be seen as “carbon neutral,” since plant crops harbor carbon, then release it when the fuel is burned. A $1 per gallon tax credit (paid to the blender) was contained in the recently passed federal energy bill, which should be a further spur to biodiesel use and reduced use of fossil fuels. But this extraordinary growth has to be put in context: The U.S. consumed 139 billion gallons of gasoline and 41 billion gallons of diesel fuel in 2004.

NBB says there is 2.5 billion pounds of waste cooking oil available every year, so there’s considerable room for growth with just that as a feedstock. And in Europe, biodiesel use has mushroomed. The European Union (EU) wants to see six percent biodiesel use by 2010 and 20 percent by 2020. To that end, the EU is subsidizing bio-crop farmers and drastically reducing taxes on the fuels. But the European Environmental Bureau, which advises the EU, favors biofuels made from waste agriculture and forestry residue over purpose-grown crops.

A study by Michael Delucchi of the University of California at Davis concluded that if forests and conservation reserve acres were converted to biodiesel crop production, net greenhouse gasses would actually increase, but this may be a false equation, since the U.S. has spare soybean oil already. Moreover, soybean production would probably be ramped up by using fallow farmland, or by switching crops, rather than exploiting forests.

Another environmental challenge is that the U.S. soy crop is largely genetically engineered (81 percent in 2003), and today’s high-volume biodiesel fuel is largely made from virgin soy. At one time more than half the U.S. soybean crop was exported, but European resistance to GE soy has largely eviscerated that trade. Of course, biodiesel production isn’t dependent on GE soy or any specific crop; that’s one of the beauties of it.

Diesel engines are up to 40 percent more fuel-efficient than gasoline power plants, which makes them a hit in Europe. But they’re also dirtier. Diesel engines have been making headway with particulate traps and low-sulfur fuels, but the Union of Concerned Scientists is still hesitant to recommend them. When they’re burning bio-fuel, however, diesels produce substantially reduced emissions of carbon monoxide and hydrocarbons, with only a slight penalty in higher levels of nitrogen oxide. And it’s a tremendous advantage that biodiesel (a mix of diesel fuel and 10 to 20 percent agricultural oil) can be burned as-is in existing diesel engines.