10 Facts About Biodiesel

This domestically-produced fuel can go a long way toward displacing petro-diesel, but we're not there yet. Here are 10 facts you need to know about this up-and-coming renewable fuel.

Biodiesel refers to a non-petroleum-based diesel fuel consisting of short chain alkyl (methyl or ethyl) esters, made by transesterification of vegetable oil, which can be used (alone, or blended with conventional petrodiesel) in unmodified diesel-engine vehicles. Biodiesel is distinguished from the straight vegetable oil (SVO) (aka "waste vegetable oil", "WVO", "used vegetable oil", "UVO", "unwashed biodiesel", "pure plant oil", "PPO") used (alone, or blended) as fuels in some converted diesel vehicles. "Biodiesel" is standardized as mono-alkyl ester and other kinds of diesel-grade fuels of biological origin are not included.

Origin

On August 31, 1937, G. Chavanne of the University of Brussels (Belgium) was granted a patent for a 'Procedure for the transformation of vegetable oils for their uses as fuels' (fr. 'Procédé de Transformation d'Huiles Végétales en Vue de Leur Utilisation comme Carburants') Belgian Patent 422,877. This patent described the alcoholysis (often referred to as transesterification) of vegetable oils using ethanol (and mentions methanol) in order to separate the fatty acids from the glycerol by replacing the glycerol with short linear alcohols. This appears to be the first account of the production of what is known as 'biodiesel' today.

1. Even Rudolf Diesel Liked Biodiesel

In a now century-old patent application, visionary and inventor Rudolf Diesel stated, "The use of vegetable oils for engine fuels may seem insignificant today, but such oils may become in the course of time as important as petroleum and the coal tar products of the present time." Clearly, that time has arrived.

2. Biodiesel is a Domestic Fuel

Biodiesel is one of the most promising replacements for traditional petroleum energy. As an alternative fuel, biodiesel is simply diesel fuel made from a variety of biomass sources. Since it can be grown domestically rather than pumped out of the ground from foreign sources, increased use of biodiesel offers significant benefits.

3. Biodiesel is Made from Many Sources

A common misconception is that biodiesel is made only from soybeans. Soy is a good source and the most common feedstock for biodiesel made in the U.S., but many other crops and plants including flax, mustard, rapeseed, sunflower, palm, hemp, jatropha, and pennycress can also be used. In addition, biodiesel can be made from animal fats and waste vegetable oil.

4. Algae is a Good Source

Perhaps the most promising source for biodiesel is algae - good old pond scum. While still on a track to becoming commercially viable, farming algae for fuel has a huge future. Under the right conditions, algae can double in weight three to four times in a single day. Importantly, the process takes in CO2 (a major greenhouse gas) while producing high grade lipids, which are basically a type of vegetable oil. Scientist are finding they can be selective about the carbon chains produced to optimize lipids for the particular type of fuel to be produced. Algae production doesn't displace farmland needed for food stocks - no soil is needed - plus it can be grown anywhere. Some estimates place commercial yields as high as 18,000 to 20,000 gallons of oil per acre annually.

5. A High Energy Balance

Biodiesel offers the highest energy balance of any transportation fuel. Taking into account planting, harvesting, production, and transporting, a DOE/USDA lifecycle analysis shows that for every unit of petro-energy required, biodiesel delivers 3.2 units of energy back.

6. Any Diesel Vehicle Can Use It

Biodiesel can run in any diesel vehicle. Green Car editors have driven a wide range of vehicles running on biodiesel, including production cars certified for use with B5, B20 in turbo diesel pickups and farm equipment, B100 in concept cars, and even pure veggie oil in properly converted vehicles.

7. B5 Biodiesel is the Norm

Progressive auto manufacturers are endorsing the use of B5 in their diesel cars and trucks, but the push for higher blends such as B20 has been stalled by a lack of universal fuel biodiesel standards. New clean diesel technology with complex and sophisticated aftertreatment exhaust systems make universal standards critical if manufacturers are to allow higher blends.

8. Fuel Viscosity is a Challenge

According to Volkswagen, the primary concern with higher blends of biodiesel isn't with the quality or even energy content of the fuel, but rather its viscosity. Modern clean diesel engines have very precise fuel delivery timing and metering, so a change in fuel viscosity makes this precise metering very challenging. In one combustion cycle, there may be as many as seven separate injections of fuel. This is one of the reasons why modern clean diesel engines are so smooth and quiet. Fuel delivery may include two pre-combustion injections, up to four main combustion injections, and even a small shot of fuel after the main combustion process for a more complete burn.

9. New ASTM Standards Will Help

The American Society for Testing and Materials (ASTM) has just approved three significant biodiesel specifications that should help widespread acceptance of B20. In addition to changes in existing standards for B100 blend stock specifications and finished specs for up to 5 percent biodiesel in conventional petrodiesel, a new third standard was adopted for blends between 6 percent (B6) and 20 percent (B20) biodiesel. Along with the federal mandate for ultra low sulfur clean diesel fuel (below 15-parts-per-million sulfur content) automakers are gaining the tools needed to support higher blends of biodiesel with confidence.

10. Important to Petroleum Displacement

World demand for oil is up and only so much diesel fuel can be refined - about 7.8 gallons - from each barrel of crude. With diesel fuel demand stressing refinery capacity worldwide it should be no surprise that diesel is more expensive than gasoline in North America. Oil prices in general are at an all-time and there's a need for petroleum displacement on many fronts. The time to get serious about biodiesel is now.