Biodiesel, like ethanol, is primarily a blend. The most common is B20, 20 percent biodiesel and 80 percent petroleum diesel. Most of today’s diesel engines can handle blends up to B20 with no modifications. In older engines (before mid 90s) natural rubber hoses and gaskets should be replaced with silicone.
Some of the pros of biodiesel include:
• It is renewable and biodegradable.
• No engine modifications (for diesel engines) required for blends up to B20.
• Blends B20 and lower are interchangeable with petroleum diesel — if you are traveling and can’t find biodiesel you can fill up with regular diesel.
• Reduction in emissions of hydrocarbons, carbon monoxide and particulate matter.
• You can make your own
Some of the cons of biodiesel:
• Though availability is increasing, it is harder to come by than petroleum diesel.
• NOx (nitrogen oxide) emission slightly higher than conventional diesel.
• No bargain at the pump, plus miles per gallon may be lower than with conventional diesel.
• Engine modifications (check warranty) called for when using blends greater than B20.
• Concerns about converting forests and/or open spaces to biodiesel plantations — for example, the decimation of Indonesian rain forests for palm production
• Biodiesel gels when temperatures fall to the freezing point. Petroleum diesel also gels, beginning at about 10 degrees Fahrenheit so additives are incorporated at the refineries — this could presumably be done with biodiesel as well
I have to admit; the idea of making my own auto fuel is intriguing. Biodiesel may be made from any type of vegetable oil and/or animal fat including used cooking oil through a process known as transesterification. This is accomplished by mixing an alcohol (commonly methanol) with a catalyst like lye. The vegetable oil is added to this mixture and glycerin settles to the bottom leaving the biodiesel on top. There are thousands of Web sites out there if you Google “make your own biodiesel.” It looks fairly simple and you can start with small batches to see if you like it. It takes about eight hours from beginning to burning and cost seems to average around 70 cents a gallon. Of course lye and methanol are volatile substances and proper care must be taken.
But the idea sure strikes a chord. We would not only be lessening our dependence on foreign oil, we would be loosening the grip Exxon-Mobile et al have on our wallets.