There’s more than one reason why a truck fleet may switch from traditional diesel or gasoline to powering vehicles with an alternative fuel. Some do it literally because they have to, thanks to various federal, state and local regulations. Others do so because they want to, to take advantage of certain benefits a specific alternative fuel may offer them or just because they see political or public relations value in going green.

Now, if a fleet wants to swear off diesel and gasoline, there’s an almost dizzying array of alternatives to pick from. All are valid ways of powering motor vehicles but all are not appropriate for all truck fleets. Choosing the right one involves weighing numerous factors, such as complying with legal regulations, taking advantage of tax incentives, tailoring vehicle specs, and setting up or accessing fueling stations.

The U.S. Dept. of Energy’s Office of Transportation Technologies (OTT) points out that many fleets are subject to alternative fuel vehicle (AFV) acquisition purchasing requirements under federal Energy Policy Act (EPAct) regulations.

DOE enforces EPAct regs through its Alternative Fuel Transportation Program and manages voluntary AFV programs through the Clean Cities program it sponsors.

Clean Cities encourages AFV use by supporting public-private partnerships that deploy alternative fuel vehicles (AFVs) and build supporting infrastructure.

To help companies meet AFV regs, OTT has developed several online tools:

  • The Alternative Fuel Vehicle Fleet Buyer’s Guide (www.fleets.doe.gov) helps fleets understand which regulations and incentives apply to them—based on their location and company description. It shows what AFVs are available, identifies where refueling stations are located, and measures the cost differences of using various AFVs vs. conventional vehicles.
  • The EPAct Fleet Information and Regulations site (www.ott.doe.gov/epact) is aimed specifically at fleets subject to various AFV acquisition requirements under EPAct. These requirements differ for different types of fleets.
  • The AirCRED Online Tool (http://appserver.es.anl. gov/aircred.html) helps calculate ozone emission-reduction credits for Clean Cities AFVs. AirCRED is based on the U.S. EPA’s MOBILE model combined with emission-test certification data for new OEM-built AFVs and their gasoline- or diesel-fueled counterparts.
  • The Federal Alternative Fuel Vehicle USER Program (www.ott.doe.gov/afvuser) site supports the expansion of alternative-fuel infrastructure by concentrating large quantities of federal AFVs and substantially increasing the use of alternative fuels in these six participating cities: Albuquerque, Denver, Minneapolis/St. Paul, Salt Lake City, San Francisco and Space Coast, FL.

As the people running the Clean Cities program like to point out, the benefits of alternative fuels—cleaner air and energy security—may be obvious, but the bottom line for fleets is their economic impact.

Of benefit to fleets that voluntarily move to AFVs are various economic incentives. The federal government offers income-tax deductions while many states have their own incentives and some private companies offer rebates or discounts. Bear in mind, most of the incentives will offset only a percentage of the initial vehicle purchase cost.

The managers of the Clean Cities program recognize that AFVs will “fit best” in applications that overcome the oft-cited barriers of limited refueling infrastructure, vehicle acquisition cost and limited operating range to make such vehicles economically feasible to fleet operations.

The Clean Cities program discusses AFVs in terms of “niche markets.” A key one for trucking is high-mileage, centrally fueled fleets. These typically consume more fuel, so over time, fleets can gain the cost savings associated with less expensive alternative fuels.

On the other hand, low-mileage, high-use vehicles—those that incur lots of idling or make repeated starts and stops—represent another valid AFV niche.

Fleets running “predictable” routes and already using centralized refueling stations that allow for overnight or off-hour refueling are also well-suited for AFVs.

No matter the specifics, according to DOE, alternative fuels are substantially nonpetroleum products that yield energy security and environmental benefits.

DOE officially recognizes the following as alternative fuels: methanol and denatured ethanol as alcohol fuels (alcohol mixtures that contain no less than 70% of the alcohol fuel); natural gas (compressed or liquefied); liquefied petroleum gas (LPG), a.k.a. propane; hydrogen, coal-derived liquid fuels; fuels derived from biological materials, and electricity (including solar energy). Also viewed by many as meeting the DOE definition of an alternative fuel is biodiesel.

Of all these, the three top contenders for trucking applications are biodiesel, LPG (propane), and compressed natural gas (CNG) and liquefied natural gas (LNG). Biodiesel is typically used as a blend called B20 that consists of 80% diesel and 20% biodiesel. The key advantage of biodiesel is that it can be delivered at the pump using the same infrastructure as diesel or gasoline.

According to Gene Gebolys, president of Boston-based biodiesel supplier World Energy Alternatives LLC, biodiesel is a diesel fuel substitute made from agricultural resources—chiefly soybeans or rapeseed (canola)—or from cooking oil recycled from restaurants. It burns in any standard, unmodified diesel engine, either in its pure form (“B100” or 100% biodiesel) or in a blend at any proportion with regular diesel.

He says the most common blend for trucking is B20, containing 20% biodiesel and 80% conventional diesel. It offers environmental benefits over “straight” diesel but at a lower cost than 100% biodiesel.

Gebolys points out that B20 is the only fuel-based technology for existing engines certified under the Clean Air Act Amendments of 1990. It’s also the minimum ratio blend recognized as an alternative by EPA.

As for its advantages, no matter the blend, biodiesel seamlessly integrates with current engine technology and fueling infrastructure. In fact, Gebolys emphasizes, it’s the first alternative fuel that can be used without purchasing special engines or building new fueling facilities.

“Biodiesel is generally accepted as offering the best performance and environmental characteristics,” states Gebolys. “It’s easy to use, better for the environment, economical, and it provides operational consistency—engine performance and vehicle range are completely unaltered.”

Along with cutting exhaust emissions, biodiesel offers fleets some other advantages, according to Gebolys. “It increases lubricity over petroleum-based diesel and has a higher cetane level for better performance. And its higher flashpoint makes it safer to handle.” Then there’s the economic angle. Gebolys calls biodiesel “pretty economical,” stating that many fleets will pay 10-15¢ per gallon over standard diesel for the B20 blend.

“The word is getting out about biodiesel,” says Gebolys. “But no alternative is the end-all, be-all fuel. There are great applications for each. Biodiesel is a good way to do it in existing diesel vehicles.”

Indeed, Gebolys contends that World Energy is “not trying to compete against other alternatives so much as we are trying to create new opportunities for fleets to transition away from what they had done in the past.”

Natural-gas vehicles (NGVs) come in two varieties—those powered by CNG and those by LNG. According to Richard R. Kolodziej, president of the Natural Gas Vehicle Coalition, a Washington, D.C.-based advocacy group, the two types have truly begun to shake out as appropriate alternatives for specific fleet types.

“For lighter-duty vehicles and those requiring less range, CNG dominates,” Kolodziej points out. “LNG is gaining ground as an alternative for fleets running heavier-duty equipment and requiring greater range before refueling.”

While he sees a “little more growth” in LNG applications, he cautions that choosing one form of natural gas power over another really comes down to duty cycle as well as fuel availability.

“For LNG, onboard fuel storage space is at a premium while CNG tanks are heavier,” Kolodziej notes. “You can get more vehicle range from LNG—but the fuel is not available everywhere. CNG tends to be cheaper—but LNG stations are cheaper to set up. So, the choice of which NGV comes down to what best fits the application.”

Kolodziej points out another trend impacting the market is the emergence of firms that will build, own and operate an LNG or CNG fueling station for a fleet under a long-term contract, making it easy for a trucking operation to switch to AFVs.

Currently, transit bus operations and trash haulers are seen as big markets for LNG, while CNG remains a favorite among centrally fueled delivery fleets.

NGVs will get a boost if legislation currently moving through Congress becomes law. The Senate version of the bill, dubbed the CLEAR Act, includes various tax credits for the purchase of alternative fuel vehicles. The credits would be determined by how “clean” the fuel is for a given vehicle. If the bill passes with all its provisions intact, Kolodziej says a Class 8 NGV could garner a $10,000 tax credit each year.

Kolodziej is confident the CLEAR Act will be included in whatever energy package is passed in the wake of the September 11 terrorist attacks. However, he also points out that many states, including New York, Texas and California, already offer their own tax credits as well as special grants that can benefit fleets adopting AFVs.

According to Roy W. Willis, president of the Propane Education & Research Council (PERC), LPG is well-suited as an alternative for gasoline or diesel power in light- and medium-duty trucks. “The way the market shakes out,” says Willis, “government and natural-gas utility fleets are the primary purchasers of CNG equipment and fleets operating in the private sector are the primary purchasers of LPG-fueled vehicles.”

He explains that while there are matching dollars for CNG installations at the state and local level that government fleets can benefit from, private-sector fleets will choose propane because the necessary infrastructure costs substantially less. “An LPG station can cost less to establish than a CNG or a gasoline/diesel station,” he states. He notes that the operating pressure for LPG, under 300 psi, is “much lower than that of CNG.”

Willis also regards propane’s range as impressive. “Given equal amounts of fuel-storage space on the vehicle, propane’s range will equal 75-80% that of gasoline.” He describes LPG today as an excellent alternative to gasoline, noting that while not impossible, the conversion of diesel to propane is “more technically challenging.”

“The biggest challenge to alternative fuels in general,” Willis adds, “is that even today, the U.S. still does not do enough to promote AFVs through tax credits and other incentives.”