Biodiesel Info

In 1890, Rudolf Diesel, the inventor of the highly efficient engine that bears his name, wanted to empower farmers by affording them an alternative to high-priced petroleum fuels. So he designed his engine to run on hemp and peanut oil.

Tests have demonstrated biodiesel's performance to be virtually the same as standard diesel. Like ethanol, biodiesel is a renewable fuel and can be produced domestically, which keeps our dollars from flowing out of the country, thus reducing our dependency on foreign oil and strengthening our agricultural economy.

Biodiesel is commonly made from a wide variety of vegetable and tree oils, animal fats and/or used cooking oils. These oils are blended with alcohol, (usually methanol or ethanol) and a catalytic agent such as sodium hydroxide. The resulting chemical reaction produces an ester and glycerin. Glycerin is commonly used in soaps and other consumer products.

Comparison of Energy Yield from One Btu of Fossil Energy Used

*Energy Yield
Net Energy (loss) or gain
(26 percent)
(17 percent)
34 percent (corn ethanol)
220 percent
* Yield in liquid fuel BTUs per Btu of fossil fuel energy dedicated
Source: USDA, Economic Research Service Report number 721

Production of biodiesel is a lower energy use and less complex process than the production of corn-based ethanol. Soy-based biodiesel has a positive energy balance of 3:1. That is, its combustion results in three times as much energy as required to convert it from its feedstock

Biodiesel blends are competitive with other alternative fuels on a life-cycle basis. And biodiesel is readily biodegradable, nontoxic and sulfur-free. Use of biodiesel quiets the engine, can eliminate black cloud emissions, reduces odor and improves engine life. The most benefits are derived from using pure biodiesel (B100). Biodiesel is the only alternative fuel to have passed the rigorous healthy effects testing of the EPA Clean Air Act. Like ethanol, biodiesel is available in a variety of blends, with B20 (20% biodiesel/80% petroleum diesel) the most common. B20 fuel is generally priced 5 to 20 cents more per gallon than regular diesel.

Biodiesel Air Pollution Reduction as Compared with Petroleum Diesel
(US Department of Energy)




Carbon Dioxide



Carbon Monoxide



Unburned hydrocarbons






Nitrous Oxides



Air toxics

-12% -20%

-60% -90%



-89% -90%

Who can use biodiesel?

B100 or pure biodiesel can be used anywhere standard diesel is used except during cold weather. In cold weather biodiesel thickens more than diesel fuel and special heating systems are required. Equipment made before 1993 may have rubber seals in fuel pumps and fuel systems that could fail if B100 is used because biodiesel is a powerful solvent. When using biodiesel in an engine, rubber seals used in the fuel delivery system should be replaced with Viton™ or other non-rubber seals.

You can use B20 or B35 biodiesel in any diesel engine, even in old engines with no changes. However, since biodiesel cleans your fuel tank and fuel system, you should replace your fuel filter shortly after switching to biodiesel. It's best to keep several spare fuel filters handy during the first few weeks after you change fuels. There are fewer cold weather problems with lesser blends of biodiesel (B20 or B35), and biodiesel mixes well with petroleum diesel fuel and stays blended even in the presence of water. Diesel fuel/biodiesel blends have superior lubricity which reduces wear and tear on your engine and prolongs engine and component life. Check with your car manufacturer to confirm that use of a particular biodiesel blend will not void your warranty.

Does biodiesel reduce greenhouse gases?

Yes. Each year, soybeans and other plants that produce oils used for making biodiesel draw carbon dioxide (CO2) from the atmosphere to build stems, leaves, seeds (which contain the oil) and roots. At the end of the year, the oil used to make biodiesel is burned and the leftover plant material decomposes, returning the carbon from the fuel and plant matter to the atmosphere as CO2. This recycling of carbon from CO2 in the atmosphere to carbon in plant material and back to the atmosphere results in no accumulation of CO2 in the atmosphere. Therefore, combusting biodiesel does not contribute to global climate change.

Carbon dioxide from the petroleum fuels used for fertilizer, farm equipment, or transportation during biodiesel production does accumulate in the atmosphere year after year. As a result, biodiesel produces 78% less CO2 than diesel fuel overall. Biodiesel emits 2661 grams of CO2 per gallon compared to 12,360 grams per gallon for petroleum diesel fuel.

How does biodiesel compare with new Ultra-Low (15 ppm) Sulfur Diesel (ULSD)?

Removing the sulfur from 500 ppm (parts per million) to only 15 ppm was a very good thing to do. However, the sulfur served as the lubricant in the diesel fuel. Therefore engines using only ULSD diesel will be subject to much higher wear factors. Fortunately a biodiesel blend as low as 3% can replace the lubrication removed from the ULSD. Much better, though, is to use at least a B20 blend which provides the engine with 20% to 50% better engine lubrication and protection than pure ULSD. This is especially important with newer diesels which have high pressure injection pumps which are subject to very high wear factors. .

Copyright © 2003 Renewable Energy Partners of New Mexico