Yesterday, it might have sounded like some kind of Utopian dream to shed our dependence on foreign oil supplies and make our own fuel in the middle of a Nebraska soybean field. But today it is not just a dream; it’s a reality — at least to a certain degree.

The product is called biodiesel — bio because it’s made out of organic material, and diesel because that’s the fuel it’s designed to replace. Biodiesel is the name given to a clean burning alternative fuel that is produced from domestic, renewable resources — primarily soybean oil, rapeseed (canola) oil, animal fats and vegetable oil. In its pure form, it contains no petroleum, and can be used as a pure fuel or can be blended with petroleum in any desired percentage. For example, B20 is a blend of 20 percent (by volume) biodiesel with 80 percent (by volume) petroleum diesel. This fuel can be used in compression-ignition (diesel) engines with no major modifications, is simple to use, biodegradable, nontoxic, and essentially free of sulfur and aromatics. Biodiesel is registered as a fuel and fuel additive with the Environmental Protection Agency (EPA) and meets clean diesel standards established by the California Air Resources Board (CARB). Neat (100 percent) biodiesel has been designated as an alternative fuel by the Department of Energy (DOE) and the U.S. Department of Transportation (DOT).

SME or SOME (Soy Methyl Ester) diesel is the most common biodiesel in the U.S. RME (Rape Methyl Ester) diesel is most common in Europe. Together, these fuels are known as Fatty Acid Methyl Esters (FAME).

Okay, so there you have a few of the technical details. But what does it all mean to you as the owner of a Caterpillar diesel-powered motorhome? There are questions to be answered: How does Caterpillar feel about you using biodiesel in one of their engines? Will it compromise your warranty? How much does this stuff cost? Why in the world would you want to change over to this type of fuel? And there are other concerns and issues as well. Let’s take a look at the questions one at a time and see what answers we can find.

1. How does Caterpillar feel about using biodiesel in its engines?

In a document issued by Caterpillar on the subject of Diesel Fuel Recommendations, there is a section that deals specifically with the use of biodiesel. Here’s what it says: “Biodiesel may be blended in amounts up to a maximum of 30 percent with an acceptable diesel fuel. This blend is acceptable provided that the biodiesel constituent meets the requirements that are outlined in Table 15 prior to blending. In addition, the final blend must meet the requirements for distillate diesel fuel that are listed in Table 13.”

Tables 13 and 15 are filled with highly technical specifications that spell out every required characteristic of these fuels. But, in short, if the fuel meets these specs, then Caterpillar is saying it’s okay to use up to a blend of 30 percent by volume. There is a special note that says: “A complete Caterpillar S-O-S Oil analysis program is required when biodiesel blends above 30 percent are used.”

And, of course, there’s the expected warning: “When biodiesel, or any blend of biodiesel is used, the user has the responsibility for obtaining the proper local exemptions, regional exemptions, and/or national exemptions that are required for the use of biodiesel in any Caterpillar engine that is regulated by emissions standards.”

2. Will using biodiesel compromise the warranty?

To quote from their own document, “Caterpillar neither approves nor prohibits the use of biodiesel fuels. Caterpillar is not in a position to evaluate the many variations of biodiesel and the long-term effects on performance, durability or compliance to emissions standards for Caterpillar products. The use of biodiesel does not affect the Caterpillar for materials and the warranty for workmanship. Failures that result from the use of any fuel are not Caterpillar factory defects. Therefore, the cost of repair would not be covered by a Caterpillar warranty.”

3. Where is biodiesel available, and how much does it cost?

Biodiesel can be purchased from any number of outlets all across the U.S. The National Biodiesel Board (NBB) maintains a list of registered fuel suppliers. A current list is available on the web at www.biodiesel.org or by calling (800) 841-5849. The cost of the fuel will naturally fluctuate, but at press time, petroleum diesel fuel was costing around $2.75 per gallon in our neck of the woods, and B20 was priced at $3.30 per gallon. Our sources told us that B20 generally goes for about 20 percent more than regular diesel fuel.

4. What will happen to engine performance if you start using biodiesel?

We have not been able to test performance with biodiesel yet, but the National Biodiesel Board claims that there is little or no difference between the performance experienced while burning petroleum diesel and biodiesel. “One of the major advantages of biodiesel is the fact that it can be used in existing engines and fuel injection equipment with little impact to operating performance. Biodiesel has a higher cetane number than U.S. diesel fuel. In over 15 million miles of in-field demonstrations biodiesel showed similar fuel consumption, horsepower, torque, and haulage rates as conventional diesel fuel.”

Caterpillar, on the other hand, says, “In a comparison of distillate fuels to biodiesel, biodiesel provides less energy per gallon by 5 percent to 7 percent. DO NOT change the engine rating in order to compensate for the power loss. This will help avoid engine problems when the engine is converted back to 100 percent distillate diesel fuel.”

5. What about cold operation and fuel gelling?

As winter approaches, or if you decide to travel to the mountains where the temperatures are cold, there are precautions to take. As you know, cold temperatures can cause petroleum diesel fuel to gel. Well, the same goes for biodiesel. Caterpillar says, “Biodiesel fuels may pose low ambient temperature problems for both storage and operation. At low ambient temperatures, fuel may need to be stored in a heated building or a heated storage tank. The fuel system may require heated fuel lines, filters, and tanks. Filters may plug and fuel in the tank may solidify at low ambient temperatures if precautions are not taken.” This is followed by advice for owners to consult with their biodiesel supplier for help in blending to get the proper cloud point for the fuel.

6. Engine component compatibility warning:

There are some concerns involving use of biodiesel, with regard to compatibility with materials used in the fuel system. In the paper issued by Caterpillar it says, “Compatibility of the elastomers with biodiesel is currently being monitored. The condition of seals and hoses should be monitored regularly.”

Some of the problems that can occur with the use of biodiesel and/or other fuel additives include swelling and hardening or cracking of some elastomer seals within the fuel system/engine, corrosion of fuel system and engine hardware (especially aluminum and zinc), solid particle blockage of fuel nozzles and passages, filter plugging, injector coking, higher injection pressures due to physical flow properties, reduced fuel system life, added stress and heat to injection components (especially rotary fuel pumps), increased pump seizures and early life failures, poor fuel spray atomization, reduced fuel economy.

The National Biodiesel Board agrees: “…biodiesel will soften and degrade certain types of elastomers and natural rubber compounds over time. Using high percent blends can impact fuel system components (primarily fuel hoses and fuel pump seals), that contain elastomer compounds incompatible with biodiesel. Manufacturers recommend that natural or butyl rubbers not be allowed to come in contact with pure biodiesel. Biodiesel will lead to degradation of these materials over time, although the effect is lessened with biodiesel blends. If a fuel system does contain these materials and users wish to fuel with pure biodiesel, replacement with compatible elastomers is recommended.”

7. Other concerns.

Biodiesel contains some residual alcohol left over from the esterification process, and this alcohol in the fuel can strip deposits from the inside of fuel tanks and fuel lines, sending the stripped-off material downstream to the fuel filter.

Caterpillar advises, “Biodiesel is an excellent medium for microbial contamination and growth. Microbial contamination and growth can cause corrosion in the fuel system and premature plugging of the fuel filter. The effectiveness of conventional anti-microbial additives when used in biodiesel is not known. Care must be taken to remove water from fuel tanks. Water accelerates microbial contamination and growth. When biodiesel is compared to distillate fuels, water is naturally more likely to exist in the biodiesel.”

Caterpillar goes on to say, “Biodiesel has poor oxidation stability, which can result in long term storage problems. The poor oxidation stability may accelerate fuel oxidation in the fuel system. This is especially true in engines with electronic fuel systems because these engines operate at higher temperatures.”

8. Why would you want to change over to this type of fuel?

Because biodiesel is currently more expensive than the regular diesel fuel, just about the only argument in favor of running biodiesel in your motorhome is for environmental reasons. Here’s what the National Biodiesel Board has to say about the clean-burning characteristics of this fuel: “Biodiesel is the only alternative fuel to have fully completed the health effects testing requirements of the Clean Air Act. The use of biodiesel in a conventional diesel engine results in substantial reduction of unburned hydrocarbons, carbon monoxide, and particulate matter compared to emissions from diesel fuel. In addition, the exhaust emissions of sulfur oxides and sulfates (major components of acid rain) from biodiesel are essentially eliminated compared to diesel. Of the major exhaust pollutants, both unburned hydrocarbons and nitrogen oxides are ozone or smog forming precursors. The use of biodiesel results in a substantial reduction of unburned hydrocarbons. Emissions of nitrogen oxides are either slightly reduced or slightly increased depending on the duty cycle of the engine and testing methods used. Based on engine testing, using the most stringent emissions testing protocols required by EPA for certification of fuels or fuel additives in the U.S., the overall ozone forming potential of the speciated hydrocarbon emissions from biodiesel was nearly 50 percent less than that measured for diesel fuel.”

So, where does that leave you? Well, at least you know what Caterpillar thinks about using biodiesel in their engines, and you go into the future (where blended fuels will undoubtedly be more common) with a basic understanding of what to expect as well as what to watch out for.

We aren’t living a Utopian lifestyle yet, but technology is bringing us alternatives that we didn’t have before. For those who choose to use biodiesel, it will be a contribution to the welfare of the environment and will help reduce our dependence on foreign oil supplies. It’s not exactly “Back To The Future” with a Flux Capacitor that eats household garbage, but it’s a start.