How Biodiesel Works

The Cons

Microalgae, organisms from which a diesel-like fuel can be derived: Cultured in the American southwestern deserts, NREL-developed microalgae may one day produce large amounts of lipids for conversion to biodiesel fuel.
Photo courtesy Paul Roessler
Microalgae, organisms from which a diesel-like fuel can be derived: Cultured in the American southwestern deserts, NREL-developed microalgae may one day produce large amounts of lipids for conversion to biodiesel fuel.

Of course, nothing is without penalty, and biodiesel does have its drawbacks. Some have to do with the fuel itself, and many have to do with the bigger picture.

One of the problems with the fuel itself is the increase in NOx in biodiesel emissions. Often, in diesel fuel manufacturing, when you decrease the amount of particulate matter in the emissions, there is a corresponding increase in nitrogen oxides, which contribute to smog formation. Though some of this can be addressed by adjusting the engine itself, that's not always feasible. There are technologies being researched to reduce NOx amounts in biodiesel emissions.

Another problem is biodiesel's behavior as a solvent. Though this property is helpful, it's kind of a double-edged sword. Some older diesel vehicles (such as cars made before 1992) may experience clogging with higher concentrations of biodiesel. Because of its ability to loosen deposits built up in the engine (which may be there from old diesel fuel), biodiesel can cause the fuel filter to become jammed with the newly freed deposits. Biodiesel manufacturers suggest changing the fuel pump shortly after switching to high-concentration biodiesel blends. Components within these older fuel systems may also become degraded. In addition to deposits within the fuel system, biodiesel also breaks down rubber components. Some parts in the older systems, such as fuel lines and fuel pump seals, may become broken down due to their rubber or rubber-like composition. This is usually remedied by replacing such components. Though many manufacturers have included biodiesel in their warranties, potential for problems could still exist. For more information on biodiesel and vehicle warranties, check out The Biodiesel Standard.

Also, in some engines, there can be slight decrease in fuel economy and power. On average, there is about a 10 percent reduction in power. In other words, it takes about 1.1 gallons of biodiesel to equal 1 gallon of standard diesel.

The major drawbacks to biodiesel are connected to the bigger picture, namely the market and associated logistics. Of these, the most important is cost. According to the EPA, pure biodiesel (B100) can cost anywhere from $1.95 to $3.00 per gallon, while B20 blends average about 30 to 40 cents more per gallon than standard diesel. This all depends on variables such as the feedstock used and market conditions.

The other, perhaps more important issue is that of amount and availability. Though biodiesel isn't necessarily produced in all 50 states, it can be made available in all of them. There are three major ways to get biodiesel, with each particular method better suited for certain types of customers. Biodiesel can be purchased directly from the supplier, from a petroleum distributor, or from public pumps. There are currently 19 NBB-members producing and marketing biodiesel in the United States. To find out how to get biodiesel, contact the National Biodiesel Board. Also, the Alternative Fuels Data Center has a search feature that allows you to locate refueling stations by city or state.

For information on locating biodiesel stations outside the U.S., contact your local biofuels agency.

So how much do we make? Given the number of different producers (i.e., federal, private, industrial) and crop sources, it's hard to attach a neat figure. Right now, the U.S. produces approximately 75 million gallons of biodiesel per year (National Biodiesel Board). This production is flexible and can be increased or decreased as needed.

Whether or not it grabs the spotlight occupied by flashier technologies, biodiesel will certainly be a constant work in progress.

Currently, the largest biodiesel market is fleet vehicles. According to the National Biodiesel Board, there are over 100 such fleets using biodiesel in the United States. These include federal and public organizations such as the U.S. Postal Service, the U.S. Air Force, U.S. Army, NASA, the U.S. Department of Energy, Duke Energy, and Florida Power & Light. Many public transportation services are also looking to biodiesel in order to complement petroleum usage. City buses such as Cincinnati Metro are also using biodiesel. Potential future targets include areas such as marine and agricultural applications and home heating.

As public awareness grows, biodiesel and biofuels in general could easily find their way into dinner conversations. Political support is also on the rise and, in the wake of legislation such as the 1998 EPACT amendment, alternative fuel sources will be a necessity in the not-so-distant future.

For more information on biodiesel, biofuels and related topics, check out the links on the next page.

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