Fun With Biodiesel
BWC Member and All Around Cool Guy
What is biodiesel?
Biodiesel is a cleaner-burning diesel fuel additive or substitute that runs in unmodified diesel engines, including those of cars, trucks, construction equipment, boats, generators, and oil home heating units. It's made from renewable sources such as soy or canola oil and can also be made from recycled fryer oil (yes, from your local restaurant) or any other vegetable oil or animal tallow.
Biodiesel is not straight vegetable oil (SVO) or waste vegetable oil (WVO), but is often made from it. In a process called transesterification, the feedstock is thinned down to remove the sticky glycerin and other impurities. This process produces biodiesel and glycerin. When purified, the glycerin can be used in several industries.
Of course, it's a diesel, a 2004 VW Jetta TDI (Turbo Direct Injection). She's been on a near-steady diet of some concentration of biodiesel since she was a wee pup, or whenever I burned off that first tank of straight petroleum diesel. At 79,000 miles, lifetime highway/city combined fuel economy - with an exuberant right foot - is 45.9 mpg, or almost the EPA estimated highway of 46 mpg. This translates routinely to 700-mile tanks.
Can you mix biodiesel with petroleum diesel?
Sure. I've run anywhere from near-B0 to B100 and back again. The number following the B is the percentage of biodiesel. B20, a common blend, is 20 percent biodiesel, 80 percent petroleum diesel.
Where do you get biodiesel?
There are fueling stations in most metropolitan areas, as well as many smaller cities. My personal enabler is Island Energy in Jamestown, RI. While not in a major metro area, Island retails both on-road biodiesel blends, as well as heating oil blends. Their biodiesel supplier is Newport Biodiesel, whose feedstock is used fryer oil (WVO) from local restaurants. I take three 5-gallon totes and a near-empty tank to Island and fuel up for a month (driving 75 miles a day). It's a Zen experience fueling with clean, clear biodiesel fuel made from the waste stream. Not to mention it reduces our foreign oil dependence and carbon emissions. And, Island's biodiesel costs about the same as petroleum diesel.
How does the car drive?
Fabulously. It's smooth, quiet and the exhaust smells great. On getting a whiff of the exhaust for the first time, my wife exclaimed "It smells like somebody's cooking something!" Being a modern turbo-diesel, it shrugs off hills with its higher torque (low-end grunt). On the freeway, you would never know it's a diesel; 60 mph turns about 2000 rpm. At those revolutions, you are at or near peak torque: just press your foot down an inch and you'll feel the push on your back immediately. No need to downshift!
Are there any disadvantages?
Of course. There is no perfect fuel, yet.
Due to its lower energy content per gallon, higher blends of biodiesel give me slightly less power and fuel economy, by perhaps 5 percent. Considering its advantages (American farm-produced, renewable and cleaner-burning), I think that's a small price to pay. As the saying goes, "Freedom Isn't Free."
Biodiesel is an excellent solvent. In older vehicles that have been burning petroleum diesel, it can loosen build-up and clog fuel filters. Also, vehicles made prior to the mid-1990's may need fuel line upgrades.
Biodiesel can gel at lower temperatures, so it's best to fuel with a reputable supplier who keeps up with seasonal changes. Here in southern New England, a commercial B20 blend does well in the winter months. Even after my car was left outside during the January 2005 blizzard and its frigid aftermath with B20 in the tank, it still started and ran great. If the low temperature is 40 degrees Fahrenheit or above, B50 is usually fine.
Some new car warranties may be affected by biodiesel use. Research your vehicle's warranty, and also biodiesel in general. Make an informed decision. Once you do, you'll know you're doing the right thing.
And have fun!
Many thanks to the following: