Q.  What is Biodiesel?

A.  Biodiesel is known by the chemical name "Fatty-Acid Methyl Ester". This fancy name just means that it's a simple molecule made from vegetable oil. It is a fuel with high-energy content and proper viscosity to operate reliably in all diesel vehicles and equipment.

Q.  What is the difference between Biodiesel and straight vegetable oil (SVO)?

A.  Straight vegetable oil is pure vegetable oil. The term "biodiesel" usually refers to alkyl ester (usually methyl ester). These esters are derived from vegetable oil. The sticky glycerine (glycerol) component of the original triglyceride (vegetable oil) is replaced with another alcohol component via the process known as transesterification. Methanol is most often used for this, since it is widely available, the least expensive, and gives a reliable chemical reaction.

Q.  How is vegetable oil converted into biodiesel?

A.  The chemical reaction to make biodiesel is fairly straight forward. Vegetable oil is a 'triglyceride' which means three hydrocarbon chains all attach to the same glycerol molecule. It takes a certain amount of catalyst (in our case, lye) to break off these hydrocarbon chains.  In the case of used cooking oils, we must add yet more lye to the reaction to neutralize the "free fatty acids" that have been formed in waste oil. This catalyst is dissolved into methyl alcohol (methanol) with a volume representing 20% of the oil we want to convert.

This 'premix' is then blended vigorously with the oil to allow complete conversion of the oil.  The blending allows the catalyst to break off each hydrocarbon chain, one by one, and bond with a floating methanol molecule to form biodiesel.  The stripped glycerol molecules fall to the bottom of the reaction tank where they are removed.  Glycerol will represent about 12%-15% of the total mix volume.

Q.  What are the advantages of using straight vegetable oil?

A.  Using straight vegetable oil is easy and frees your reliance on chemicals. Methanol is often used to make biodiesel and even though it is called "wood alcohol", it has not been made commercially from renewable sources like wood for many years, but rather from non-renewable natural gas).

Q.  What are the advantages of using biodiesel?

A.  SVO use, by contrast to biodiesel, requires a heated fuel system, and most often a second fuel tank and filter, to be able to start the engine, move the SVO from tank, through fuel lines, filter, injection pump and injectors, as well as to accomplish the best atomization within the engine (lowest emissions, and least likely to cause harm to the engine).

Q.  Which is better, biodiesel or SVO? 

A.  There really is no "better". Some people enjoy the chemistry challenges of making biodiesel, and others prefer the more "mechanical" nature of SVO conversion. In fact, a lot of people do some of each, using "less suitable" oil to make biodiesel, and the better oil for SVO. Then they use the biodiesel for start/stop fuel in a two-tank SVO system.

Q.  Can biodiesel be used just like diesel?

A.  Biodiesel can be used to displace petroleum-based fuel in diesel engines, which account for approximately 22% of the fuel consumed in the transportation sector (EIA Annual Energy Outlook 2006 - available: http://www.doe.eia.gov/aeo2006/).  It can be also be used in other combustion equipment (e.g., boilers and heaters) as a replacement for petroleum distillate oil fuels. 

Q.  If I add a SVO kit to my car, what fuels can I use?

A.  Diesel, biodiesel, new or used vegetable oil. You can use any of these fuels in any proportion.

Q.  How well does SVO work in cold weather?

A.  Depending on the oil you use and the vehicle condition, SVO systems can be specified and equipped for cold weather use. Options such as tank heaters, heat exchangers, and pad heaters will work well. 120V engine block heaters, oil pan pad heaters, propane or diesel-fired "parking heaters" for pre-heating the engine are a very good idea, since they will reduce the time to "switch-over", and minimize the required "purge" times when using "two-tank" systems, and will extend the lower ambient temperature limits of "single tank" systems.

Q.  What kind of oil can be used to make biodiesel?

A.  The current conventional feedstock sources for producing biodiesel are oil crops (e.g., soybean, canola), waste vegetable oils from restaurants and other food processing plants, or animal fats. Proposed unconventional (not yet commercially available) feedstock sources include oil extracted from wastewater sludge, algae, and corn oil from ethanol processing.

In the United States, biodiesel is made primarily from soybean oil and secondarily from a product called yellow grease, which is essentially used restaurant cooking oil. It can also be made from tallow, a hard fat that comes from cattle or sheep, which is frequently used to make soap and other products.

In Europe, where there is a thriving biodiesel industry, the fuel is made from rapeseed oil, which is produced from a plant that is in the mustard and turnip families. The European variety of rapeseed is not grown in the United States due to the climate it needs to thrive, however the canola variety of this plant is grown in some parts of the country.

Q.  What oil is best to use as SVO?

A.  Canola oil (rapeseed oil, and the related mustard oil) is one of the best and can be located with varying degrees of effort in most areas of Canada and the US, as used cooking oil. Other oils may be less suitable. Basically, a low iodine value oil that resists oxidation/polymerization, and that also had lower free fatty acid (FFA) values, is best. Be aware that some oils have higher Iodine Values (IV is a test method, there is no Iodine in the oil itself) than others, as new oils, and also be aware that FFA values increase as oil is used in a fryer.

Use Biodiesel or Straight Vegetable Oil in your Diesel Engine!!

• Reduce Emissions
• No sulfur emissions (plant oils have negligible sulphur) = no acid rain contribution
• Reduce soot (diesel smoke) 30-60%
• Eliminate Carbon dioxide emissions
• No global warming contribution
• Renewable
• Biodegradable
• Recycle waste - used cooking oil
• Energy Independence
• On-farm fuel production
• Economical
• Fastest payback of any renewable energy
• Easiest, least expensive "solar power"

Updated April 2008.