Biodiesel FAQs

Here are answers to some of the most frequently asked questions about biodiesel. Whether you’re new to biodiesel or looking for technical details, you’ll find clear and helpful information below.

What is Biodiesel?

Biodiesel is a clean-burning, renewable alternative fuel produced from domestic resources such as vegetable oils, animal fats, and recycled cooking oil. It contains no petroleum, but it can be blended with petroleum diesel at any ratio. Biodiesel can be used in standard compression-ignition (diesel) engines with little or no modifications.

It is simple to use, biodegradable, nontoxic, and essentially free of sulfur and aromatics.

Is Biodiesel the same as raw vegetable oil?

No. Biodiesel is produced from fats or oils through a chemical process called transesterification. This reaction removes glycerin and creates fuel-grade biodiesel that meets strict industry standards (ASTM D6751).

Raw vegetable oil does not meet these specifications, is not registered with the EPA, and is not a legal motor fuel. Only biodiesel that meets ASTM D6751 and is properly registered can be sold and used as fuel.

Is biodiesel used pure or blended?

Biodiesel can be used as a pure fuel (B100) or blended with petroleum diesel in any percentage. B20 (20% biodiesel + 80% petroleum diesel) is the most common blend and offers significant environmental benefits with minimal cost increase.

Is biodiesel approved for use in the United States?

Yes. Biodiesel is fully registered as a fuel and fuel additive with the Environmental Protection Agency (EPA). It meets clean diesel standards set by the California Air Resources Board (CARB) and has been designated as an alternative fuel by the Department of Energy (DOE) and the Department of Transportation (DOT).

How do biodiesel emissions compare to petroleum diesel?

Biodiesel is the only alternative fuel to have fully completed the health effects testing required by the 1990 Clean Air Act Amendments. When used in a conventional diesel engine, it significantly reduces unburned hydrocarbons, carbon monoxide, and particulate matter. Sulfur oxides and sulfates (major contributors to acid rain) are essentially eliminated.

The overall ozone-forming potential of biodiesel emissions is nearly 50% lower than that of petroleum diesel.

Can biodiesel help reduce global warming?

Yes. According to a 1998 lifecycle study by the U.S. Department of Energy and the U.S. Department of Agriculture, biodiesel reduces net carbon dioxide emissions by 78% compared to petroleum diesel. This is because biodiesel has a closed carbon cycle — the CO₂ released when it is burned is re-absorbed by the plants grown to produce the next batch of fuel.

Does biodiesel cost more than petroleum diesel?

Biodiesel may have a slightly higher upfront cost in some markets, but many fleet operators find it to be their lowest-cost strategy to meet environmental regulations. Importantly, biodiesel requires no major engine modifications, so fleets can keep their existing vehicles, parts, and mechanics.