As "clean diesels" start appearing in the U.S. automotive market, you'll hear a lot more about using biodiesel to reduce our dependence on foreign oil and its impact on the environment. But the question becomes, is it really safe for your car?
Weighing the Risks One of the most challenging issues concerning biodiesel fuel has been its quality and the long-term effects of using it in a diesel-powered vehicle. To help address these concerns, the National Biodiesel Board worked with regulators, auto and engine manufacturers and the biodiesel industry to create national standards for both pure biodiesel (called B100) and biodiesel blends (most commonly B2, B5, B20, where the number represents the percentage of biodiesel blended with petroleum diesel). Biodiesel standards are more stringent than U.S. gasoline and petroleum diesel standards, the latter fuel being not heavily regulated. However, adherence to these standards is voluntary and not all biodiesel producers meet them, which means the consumer can encounter quality issues. Inconsistent quality among producers is an issue that has everyone — the biodiesel industry, automakers, engine suppliers and consumers — concerned.
Fueling stations must treat biodiesel a bit differently from other fuels. Because it is made with vegetable-based products, storage temperature is more critical than with petroleum diesel. If it sits in a warm storage tank for too long, it can grow mold, and if it is stored at too cold a temperature, it will thicken and could be difficult to dispense. These problems primarily occur if the biodiesel is not used quickly enough, so fuel stations can significantly reduce these issues by simply buying only enough biodiesel to meet demand.
While these problems can also occur after the biodiesel has been pumped into a vehicle, it is more important for owners to watch for signs of clogs in fuel filters and systems — particularly when biodiesel is first introduced to a vehicle's fuel system and especially if the owner is using pure biodiesel (B100). All biodiesel acts as a solvent, meaning it can loosen deposits that are stuck in fuel lines and in the fuel tank, which can then clog fuel filters, injectors and other parts of the fuel system. Experts indicate that this is a greater issue when B100 is used with older diesel vehicles (because higher mileage generally means greater deposits) and with the newest fuel injection technology, which operates at much higher pressure.
Since these issues typically relate only to pure biodiesel (B100), not blends, one might make the assumption that the risks would be significantly less or perhaps even negligible with low-biodiesel blends. This assumption is a dangerous one, however, since the risk depends largely on the quality of the biodiesel produced. The Worldwide Fuel Charter, a list of fuel requirements endorsed by auto and engine manufacturers, only recommends the use of biodiesel blends of up to 5 percent (B5) in the United States. Some automakers, including Ford, Chrysler, General Motors, Mercedes-Benz and Volkswagen also take this stance, though Chrysler and General Motors approve the use of B20 in some fleet applications of heavy-duty pickups.
Still, some automakers are cautious. For example, Mercedes-Benz's limited warranty won't cover vehicle damage caused by fuel that does not meet Mercedes-Benz-approved fuel standards, according to a spokesperson for Mercedes-Benz USA.
Is Biodiesel Safe for My Car? With all these cautionary statements by automakers, many consumers are left wondering if biodiesel is safe to run in their vehicles. "Quality standards are the main concern for any U.S. [petroleum] diesel fuel; this is an even bigger concern for biodiesel," said Keith Price, spokesman for Volkswagen of America. "We do think there is potential for biodiesel blends once the quality standards are improved even further."
While no automaker recommends the use of biodiesel in quantities higher than B5 for passenger vehicles in the U.S., many have done research on the use of biodiesel blends up to B20 and feel confident in its performance, so long as the fuel is of high quality.
"If diesel owners choose to use biodiesel fuel, they need to be confident in the quality of the fuel," said Coleman Jones, GM powertrain biofuel implementation manager. "This is why GM has made its initial offering of B20 biodiesel fuel as an option for fleet users only. We would like to see the biodiesel industry match the ethanol industry in complying with the appropriate relevant standards to control the quality of the fuel that is made available to consumers."
Where opinions deviate greatly is with biodiesel blends containing more than 20 percent biodiesel. Some sources claim that even if produced by a reputable manufacturer, 100 percent biodiesel (B100) should not be used, as it would likely result in engine damage. Others feel that it may be possible to use B100 without any adverse effects as long as it is of high quality.
Making Biodiesel at Home There appears to be a consensus that purchasing used restaurant cooking oil and making your own biodiesel fuel at home using a kit is not a good idea.
Despite the fact that there are a number of companies marketing these systems and that instructions on making biodiesel at home are prevalent on the Internet, experts agree that these homegrown systems are likely to cause more harm than good.
Dick Baker, corporate technical specialist for Ford's Advanced Diesel Systems group, acknowledges that there are a number of individuals who are taking the make-it-yourself approach and seem to be having positive results. "A diesel engine will burn lots of types of oils and is quite tolerant of these products in the short term. The long-term effects, however, are another story," he said.
Before you see your neighbor pumping biodiesel into his new diesel sedan, you'll probably pass by a commercial truck running on it. Safeway, Inc., one of the country's largest food and drug retailers, recently announced that its fleet of more than 1,000 trucks will now operate on B20. While it may seem like just another drop in the bucket on a national scale, increased demand from business will reinforce the need for increased biodiesel availability. In the long run, this will help the consumer as well.