The following post was originally published on one of our partner blogs.  In our efforts to bring content relevant to residential readers, we will begin to post more information related to transportation energy efficiency as well as home energy efficiency.

We hope you enjoy this content related to using a renewable fuel source in the most efficient internal combustion engines: diesel.

Any diesel engine can run on biodiesel.  Is that a true statement?  Are there any issues to deal with or do you just dump the "biodiesel" into the engine?  What is biodiesel anyway?

There are lots of questions that should be answered when you begin to peel back the onion on running your vehicle on biodiesel.  This article will attempt to demystify biodiesel and answer some of those questions.  This is part of our "no nonsense" series on biofuels as a partial solution to wean us off of petroleum.

What is Biodiesel?

Biodiesel is a fuel made from renewable plant oils and animal fats.  It differs from plant oils and animal fats in that it must first be reacted with an alcohol and catalyst before it becomes fuel.  After the reaction, the biodiesel must be separated from the non-reacted oil/fats, leftover catalyst and glycerine by-product.  The resulting fuel must also be washed and dried to remove any impurities before the fuel is ready to run in a diesel engine.

If you use biodiesel in its purest form in an engine, this is known as B100 or 100% biodiesel.  When the pure biodiesel is blended with regular diesel in different proportions, it is still considered to be "biodiesel."  It has different designations depending on the percentage of biodiesel that is mixed with the regular diesel fuel.  The most common commercial blend of biodiesel consists of 20 percent pure biodiesel and 80 percent regular diesel.  This is known as "B20."  Some vehicles are only warranted to run on B5 or 5% pure biodiesel.  This is such a low percentage of biodiesel, most consider this to be regular diesel fuel with an additive.  It is similar to gasoline that uses a 5% ethanol additive.  (oil companies used the toxin MTBE until they realized how bad it is and switched to ethanol)

The American Society for Testing and Materials created a standard testing procedure for biodiesel known as ASTM D6751.  Biodiesel for commercial sale must be tested to make sure it meets this standard before it is approved for sale as a fuel.  For more information on the process of making biodiesel, see these NotPetroleum-approved links for information and technical discussion:

Collaborative Biodiesel Tutorial

InfoPop Biodiesel Discussion Forum

What is NOT Biodiesel?

Biodiesel is NOT waste vegetable oil, plant oil or animal fats.  Those are all feedstocks that are used for making biodiesel.

Biodiesel is NOT vegetable oil mixed with diesel.  Some people use this as a fuel in diesel engines but it is not biodiesel.  This can work as a fuel since it cuts down the viscosity or "thickness" of the vegetable oil so that it will run in a diesel engine.  This is not recommended as a fuel for modern diesel engines.  It can work in some engines but requires an in-depth knowledge of the internal components of different types of diesel engines and some understanding of thermodynamics.  If you are not a tinkerer and are not technical, don't try this.

Does Biodiesel "just work" with a diesel engine?

Yes and No.  You can dump biodiesel in a diesel engine and it will burn as fuel.  However, since biodiesel is an alcohol, it will eventually degrade seals and hoses that are not rated for alcohol.  The most common material for making alcohol-resistant seals and hoses is called a "fluoro-elastomer."  The most common version of this is called Viton and is made by Dupont.

If you are running B20 biodiesel in a modern diesel vehicle, the dilution factor will help prevent this degradation.  Also, most modern diesel engines use viton seals and hoses with viton lining.  If you would like to use pure biodiesel (B100) in a vehicle, make sure your seals and hoses are viton or have been replaced with fluoro-elastomer materials.  Most auto parts stores carry "high pressure fuel hose" which normally has a fluoro-elastomer lining and comes in several sizes.  To be certain, make sure the host is marked with the following designation: "SAE30R9."  Hose with this marking has the viton lining.

Most vehicles are warranted for only B5 and some for B20.  If you run less diluted versions of biodiesel you will void the warranty.  Make sure you take this into consideration before running more than the recommended blend of biodiesel in your vehicle that is still under factory warranty.  One last word to the wise: remember that viton is "alcohol resistant" and not "alcohol proof."  If you run B100 on a regular basis, you will eventually have to replace the viton seals and hoses.  However, the life is probably closer to the regular replacement cycle on hoses that are used with regular diesel fuel.

Do I need to "convert" my car to run on biodiesel?

The only conversion necessary is to make sure that your hoses and seals are made from an alcohol-resistant material like Viton.  (see information in the section above)

How do I make Biodiesel?

Biodiesel does not require a special facility or laboratory to produce the reaction.  However, it can be dangerous and could cause bodily injury or death.  I would NOT recommend doing this in your garage or at home.  There are good instructions on the internet on how to make biodiesel yourself and some commercial devices to make the process less cumbersome if you have a safe place to make it and have knowledge of Chemistry.  Proceed at your own risk!

Where do I buy Biodiesel?

The best way to find commercial biodiesel retailers in the United States is to use the biodiesel finder site at the National Biodiesel Board.  If you are located in other regions, I would recommend googling "biodiesel" and your location to do some research on where to buy commercial biodiesel.  Make sure you are buying from a licensed facility.  If not, make sure the fuel is tested and certified ASTM D6751 to prevent damage to your vehicle from dirty, un-reacted fuel or worse.

Can I run my car on vegetable oil?

You can run a diesel vehicle on vegetable oil.  However, it is much more difficult than using biodiesel.  I used to teach a class to elementary and middle school children on running cars on vegetable oil.  The easiest way to explain it to them was to tell them there are three basic steps to making waste vegetable oil work as a diesel fuel: "Get it CLEAN, Get it DRY and Get it HOT"

There is much debate around what is required to make a diesel engine run on vegetable oil and which types of engines will work.  Here are some NotPetroleum-approved links to find out more information on how to make this work.

Greasology WVO Tutorial

InfoPop SVO Discussion Board

What do I have to do to make waste vegetable oil work as a fuel?

Get is CLEAN, Get it DRY and Get it HOT.  Choose an older diesel Mercedes built before 1986 if you want to experiment. However, make sure you like to tinker with car maintenance yourself since these cars are old and require a lot of regular maintenance.  After all, they are at least 25 years old and are often neglected.

Do NOT buy a new $50k diesel truck and hand it over to a hippie to convert it to vegetable oil.  There are sophisticated vegetable oil conversion kits that will work with new trucks if they are installed by a professional.  If you want to go this route, google "Frybrid" and "Vegistroke."  These systems do work but only if you are experienced at preparing the oil as a fuel.

I hope this has given you enough information to better understand biodiesel and how you can use it as an alternative to petroleum.  Biodiesel isn't the only solution for getting us off of our addiction to petroleum but it certainly can be a part of the solution and/or serve as a bridge to future technologies that are NotPetroleum!