Modify my car

What is biodiesel? It's a mix of modified vegetable oils (that's the "bio" part) and conventional diesel fuel. In 2011, more than a billion gallons of biodiesel were produced in the U.S. There are 205 EPA-registered plants, with annual capacity of more than three billion gallons. The market for biofuels remains relatively small but growing, and it supplies about one percent of the world's transportation fuel.

A joint study by Departments of Energy and Agriculture estimated that advanced biofuels could provide 37 percent of our transportation fuel in the next 20 years. It even said that biofuels could be 75 percent if cars and trucks doubled their fuel economy—which is what auto manufacturers basically have to do with the federal fuel economy regulations that require cars to reach 54.5 mpg by 2025.

How is biodiesel sold?

Biodiesel is usually sold in ratios of 10- or 20-percent modified vegetable oil and 80- or 90-percent conventional diesel. These fuels are called B10 or B20. The B factor tells you the percentage of modified vegetable oil. In other words, B100 is pure modified vegetable oil, while B20 (a popular fleet fuel) is 20 percent modified vegetable oil and 80 percent regular diesel.

Soybean oil is usually the raw material in the vegetable part of the fuel, but rapeseed oil and animal fats can be used, too. Experiments with Vitalis, Cheese Whiz and Soy Pez remain inconclusive.

Will I have to modify my diesel vehicle to use biodiesel?

Not if you use fuels with a relatively small percentage of vegetable oil, such as B10 or B20. These fuels can be used in a regular diesel vehicle without any special concerns. One minor note is that biodiesel is a solvent, so when used initially it might loosen deposits and clog your fuel filter. Check that filter regularly and you should be fine.

Where do I get it?

Biodiesel is sold commercially.

At the present, there are more than 1, 800 public locations in the U.S. that sell biodiesel. That number is going up, but it's still infinitesimally small, compared to the estimated 160, 000 gas stations in the country. You can also purchase biodiesel in 55-gallon drums, delivered right to your door. (Really want some? Check out our resources area.)