Amidst all the brouhaha about natural gas, the biodiesel option appears to have gone quiet. It still has a near-cult-like following in some quarters, but in the freight-transportation mainstream, biodiesel is a very small player at this point.

You can see the swing in Frost & Sullivan's latest Voice of the Fleet Manager survey. The industry research group's Sandeep Kar notes that in 2010, 78% of the 100 fleet managers in the survey ranked biodiesel highly, compared to only 44% this year. Meanwhile, only 22% were interested in natural gas in 2010, up to 56% today.

There have been setbacks recently for biodiesel fans. The National Biodiesel Board was disappointed after the Senate voted down two amendments that would have extended the biodiesel tax incentive - called the Federal Blender's Credit - through the end of the year. Congress allowed the $1-per-gallon biodiesel incentive to expire on Dec. 31, 2011, despite the fact that it had helped the biodiesel industry achieve record production last year of nearly 1.1 billion gallons. That easily beat the 800-million-gallon target required under the EPA's Renewable Fuel Standard, and it compares to a paltry 15 million gallons just 10 years ago. The NBB is still pressing for an extension.

The credit was absent throughout 2010 as well, and the biodiesel industry saw a 42% drop in production that year as prices increased and demand dropped.

"With petroleum prices where they are now, we shouldn't need any reminders about how important it is to continue developing new American energy sources," NBB vice president Anne Steckel said in a recent submission to Congress.

Biodiesel prices are slightly higher than regular diesel, creating another stumbling block. The Department of Energy notes that biodiesel prices vary across the country and tend to be slightly higher than those for petroleum diesel. The Clean Cities Alternative Fuel Price Report as of January 2012 saw B20 biodiesel selling at an verage price of $3.95 per gallon, compared to $3.86 for regular diesel. Biodiesel also results in slightly lower fuel economy and power - about 2% for B20, says the DOE.

The higher prices have dampened enthusiasm in some quarters, but fleets using it include the New York City Sanitation Department, the Missouri Department of Transportation, Florida Power & Light, Poland Spring, Sysco and Whole Foods, according to the Biodiesel Board.

Biodiesel Feedstocks

There are some 103 biodiesel plants in the U.S. with operable capacity of 2.1 billion gallons a year, according to the Energy Information Administration in Washington.

Biodiesel can be made from many types of feedstock. In the U.S., it's most commonly soybeans, followed by canola oil. (Although the oil yield from canola is about three times greater than from soybean, making it a much more efficient feedstock, it's a distant second in the U.S., but it's the most common feedstock in Canada.)

"White grease" (lard) and "yellow grease" (used cooking oil from fast-food and other restaurants) are also major sources. In fact, used cooking grease has become a target of thieves, particularly in California, where a gallon of grease that was worth about 6 cents five years ago now sells for nearly 50 cents a gallon.

Overseas, rapeseed is the foundation for the vast majority of biodiesel fuel sold in Europe, where the industry is far more advanced than it is here. Germany, for example, has almost 2,000 biodiesel retail filling stations. Jatropha, richer in oils than soybeans or even canola, is coming into wider use in south Asia as a biofuel feedstock.

A feedstock some believe is promising is algae, because it does not compete with food needs and could produce many times the oil per acre that other crops do. Earlier this year, President Obama announced the Energy Department will make $14 million available to support research and development of biofuels from algae, which it said has the potential to replace up to 17% of the United States' imported oil for transportation. SunEco is currently finalizing a "million mile test" with J.B. Hunt Transportation with algae-based biofuel produced by Extreme Biodiesel.

However, it's tough to bring new-generation biofuels to market. In late April, Royal Dutch Shell and Ottawa's Iogen Corp. killed a fairly advanced plan to build a cellulosic ethanol plant in Manitoba. Their joint venture, Iogen Energy, aimed to make ethanol - a gasoline replacement - from biomass such as municipal waste, wood chips and the stems of food crops. Usually, it's made from corn or sugar cane, a much easier process, but one with capacity limits. A cellulosic-process plant is about five times more expensive than one required for simply fermenting the sugars in corn. Clearly, at this stage, government subsidies are required.

Which Blend?

If you plan to use biodiesel, a decision about the blend is required. A so-called B5 blend is 5% biodiesel mixed with 95% petroleum diesel. It's been proven to work well in cold weather after testing in Alberta, and it's approved by all engine makers as far as we know.

A B20 blend is a little different and is generally not recommended for winter use. There isn't across-the-board approval from the engine world either, so it's crucial that you check with your engine supplier before you make any fuel moves.

No matter which blend you propose to use, you'll need to be sure that the fuel contains biofuel blend stock compliant with the American Society for Testing and Materials (ASTM) D6751 and blended fuel compliant to ASTM D975. All engine makers will insist on that or something like it.
Another quality standard is BQ-9000, the National Biodiesel Accreditation Program. It combines ASTM D6751 and a quality systems program that includes storage, sampling, testing, blending, shipping, distribution and fuel management practices.

In sampling a few engine-maker policies, we found that Hino supports the use of B20 biodiesel in its hybrid-electric truck, as well as in its complete line of Class 4 and 5 cabover and Class 6 and 7 conventional trucks. All 2011 and later trucks powered by Hino's J-Series engines are approved to use B20 biodiesel. Hino trucks built prior to the 2011 model year are approved to use no more than B5.

Cummins also allows a B20 biodiesel blend in these current-model on-highway Cummins engines: the ISX, ISM, ISL, ISC and ISB engines certified to EPA '02 and later emissions standards. Many off-highway engines also qualify, as does the Dodge Ram truck when in municipal, government and commercial fleet use only, and only with select model-year vehicles.

Like Hino, Cummins is pretty particular about the biodiesel fuel used. The original B100 must conform to ASTM D6751 prior to blending, and the finished B20 blend must conform to ASTM D7467. The latter is a new spec that applies to biodiesel blends of B6 to B20, and it replaces Cummins' previous Engine Manufacturers Association B20 requirement.

"Customers are required to purchase the biodiesel blend from a BQ9000-certified marketer," Cummins says, as does Hino. "The B100 fuel used in the blend must be sourced from a BQ9000-accredited producer."

Detroit Diesel engines, all of them, are good for blends up to B5, but after that, there are qualifications. Biodiesel blends above 5% are not allowed in MBE 900/4000 engines, but B20 is allowed in Series 60, DD13, DD15 and DD16 engines. Biodiesel blends above 20% aren't allowed in any Detroit Diesel engines.

A technical bulletin from Navistar suggests that B5 biodiesel is OK in International engines and will not void the warranty if the fuel meets ASTM D6751 and D975 standards. A B20 blend might be different and is to be used — in 2007 and later MaxxForce engines only — "at the discretion of the customer." B20 "will not automatically void the warranty" unless an engine failure can be attributed to fuel "not provided by a BQ9000-certified fuel supplier, not meeting the EMA B20 Test Fuel Specification."

In other words, tread carefully

Mack allows B20 on all engines, according to Dave McKenna, director of powertrain sales.

"We were much more cautious with the B20 and EPA 2010 [engine] combination, as some biofuels can cause higher combustion temperatures [and more NOx] than anything else," McKenna says. "All distributors claim ASTM compliance, but somehow, I doubt the veracity..."

Another issue with inconsistent use of biodiesel is what McKenna calls the laxative effect. Biodiesel has a solvent-like action on carbon deposits, loosening them, which then clogs fuel filters.

Mack's sticking with B20 for now, McKenna says. "My biggest – and only — concern with any biodiesel is the proper processing and grading. We have seen samples of B5 closer to 13% and B20 at less than 15%. So it is the quality, in a nutshell."

As with any departure from normal practice, the use of biodiesel demands a deliberate approach that starts with your engine maker's advice.

Editor-in-Chief Deborah Lockridge contributed to this article.