How Biodiesel Works

The Pros

Biodiesel has several key advantages:
  • Biodiesel is environmentally friendly.
  • It can help reduce dependency on foreign oil.
  • It helps to lubricate the engine itself, decreasing engine wear.
  • It can be used in almost any diesel with little or no engine modification.
  • It is safer than conventional diesel.
One of the major selling points of biodiesel is that it is environmentally friendly. Biodiesel has fewer emissions than standard diesel, is biodegradable, and is a renewable source of energy.

Emissions control is central to the biodiesel argument, especially in legislation matters. There are a few components of emissions that are especially harmful and cause concern among scientists, lawmakers, and consumers. Sulfur and its related compounds contribute to the formation of acid rain; carbon monoxide is a widely recognized toxin; and carbon dioxide contributes to the greenhouse effect. There are also some lesser known compounds that cause concern, such as polycyclic aromatic hydrocarbons (PAHs), ring-shaped compounds that have been linked to the formation of certain types of cancer. Particulate matter (PM) has negative health effects, and unburned hydrocarbons contribute to the formation of smog and ozone.

Biodiesel does reduce hazardous emissions. Of the current biofuels, biodiesel is the only one to have successfully completed emissions testing in accordance with the Clean Air Act.

Average Biodiesel Emissions Compared to Conventional Diesel
Emission Component B100 B20
Total Unburned Hydrocarbons -67% -20%
Carbon Monoxide -48% -12%
Particulate Matter -47% -12%
NOx +10% +2%
Sulfates -100% -20%
PAH -80% -13%
Source: National Biodiesel Board

In addition, B100 can reduce CO2 emissions by 78 percent and lower the carcinogenic properties of diesel fuel by 94 percent (National Biodiesel Board, U.S. DOE Office of Transportation Technologies).

Another feature of biodiesel is that it is biodegradable, meaning that it can decompose as the result of natural agents such as bacteria. According to the EPA, biodiesel degrades at a rate four times faster than conventional diesel fuel. This way, in the event of a spill, the cleanup would be easier and the aftermath would not be as frightening. This would also hold true for biodiesel blends.

Biodiesel could also lower U.S. dependence on imported oil and increase our energy security. Most biodiesel in the U.S. is made from soybean oil, which is a major domestic crop. With U.S. petroleum demands increasing and world supply decreasing, a renewable fuel such as biodiesel, if properly implemented, could alleviate some of the U.S. energy demands.

Biodiesel also contributes to an engine's lubricity, or its ease of movement. Biodiesel acts as a solvent, which helps to loosen deposits and other gunk from the insides of an engine that could potentially cause clogs. Since pure biodiesel leaves no deposits of its own, this results in increased engine life. It is estimated that a biodiesel blend of just 1 percent could increase fuel lubricity by as much as 65 percent (U.S. DOE Office of Transportation Technology).

Biodiesel is also safer. It is non-toxic (about 10 times less toxic than table salt) and has a higher flashpoint than conventional diesel. Because it burns at a higher temperature, it is less likely to accidentally combust. This makes movement and storage regulations easier to accommodate. Next, we'll look at the cons and the future of biodiesel.