Fuel: Diesel & Beyond

The days are gone when Fill 'er up meant fuel up with good old #2 Diesel and be on your way . Already, some fleets are running on once-exotic fuels like biodiesel and ethanol and turning to advanced hybrid technologies to help power their trucks more efficiently and Yes, the future is in sight but it is not at all clear which alternatives beyond diesel are the best choices to power trucks. The staggering

The days are gone when “Fill 'er up” meant fuel up with good old #2 Diesel and be on your way .

Already, some fleets are running on once-exotic fuels like biodiesel and ethanol and turning to advanced hybrid technologies to help power their trucks more efficiently and “greenly.”

Yes, the future is in sight but it is not at all clear which alternatives beyond diesel are the best choices to power trucks.

The staggering rise in the cost of fossil fuels — be it the ultra-low sulfur diesel that powers most medium- and heavy-duty trucks or the unleaded gasoline that light trucks and cars use — along with the swelling tide of public and private environmentalism and the desire of developed nations like ours to be more energy-independent, coupled with technological breakthroughs, are driving the development of a rich menu of alternative ways to power vehicles.

The trick is figuring out not just which new fuel — or fuels — are appropriate for a given fleet right now but also which might deliver better results in a few to some years down the road.

In terms of dealing with the plethora of choices emerging, one positive to bear in mind is that trucking has historically been adept at working with — and taking advantage of — equipment options that are not one-size-fits-all solutions.

Zeroing in on all this choice, it would be nice to state that pumping biodiesel into medium and heavy trucks and ethanol into light trucks would amount to a magic potion for trucking, allowing fleets to be green and save green while running fuels that seem little different than what they have burned for decades.

But, again, things are not that simple. Both biodiesel and ethanol (collectively they are biofuels) hold great promise but they're not expected to win converts without a fight. There remains plenty of opportunity for natural gas vehicles (NGVs) too.

And gaining attention in just the past few years are medium- and heavy-duty hybrid powertrain setups. Much further down the developmental highway are hydrogen-powered fuel cell and full electric power.


What are biofuels and why are they all the rage? Biodiesel and ethanol are derived from biomass energy, gained from plants and plant-derived materials. Wood is the oldest and still the largest biomass energy resource; other sources include food crops, grassy and woody plants, residues from agriculture or forestry, and the organic component of municipal and industrial wastes, including the fumes known as methane gas.

According to the U.S. Dept. of Energy's National Renewable Energy Laboratory (NREL), tapping biomass energy can greatly reduce greenhouse gas emissions.

The key thing about biofuels is they can be mixed with diesel or gasoline, to create biodiesel and ethanol respectively, to lower exhaust pollution by up to 30%, states a recent Michelin report on “sustainable mobility.”

What's more, NREL says using biofuels can reduce dependence on foreign oil because they are the “only renewable liquid transportation fuels available.”

The real kicker, and this is where agronomics comes into play, and farm-belt politicians step right in, is that “biomass energy supports U.S. agricultural and forest-product industries.”

The “feed stocks” in this country that make up biomass fuels are corn (for ethanol) and soybeans (for biodiesel), which NREL calls “surplus crops.”

The laboratory adds that in the near future “with NREL-developed technology” agricultural residues such as corn stover (the stalks, leaves, and husks of the plant) and wheat straw will also be used.

“Long-term plans include growing and using dedicated energy crops, such as fast-growing trees and grasses, that can grow sustainably on land that will not support intensive food crops,” states NREL. Translation: A new industry has been born that not only benefits large-scale farmers, but also communities where biofuel plants are sited. This is the kind of progress that won't be easily stopped let alone slowed.

That in a soypod (or cornhusk) is why trucking is hearing so much about biofuels. However, whether you can fuel your truck or car with a biofuel at this time depends on where you are. Think corn, think soybeans. If your trucks are in the Farm Belt or traveling through it, chances are you can. If not, well, then no.

If you can access them, the good news about biodiesel and ethanol is these fuels can be used by fleets with essentially no extra investment because they will power existing equipment with few if any modifications and no new fuel-distribution infrastructure is needed.

In addition, a lot of spadework has already been done by advocacy groups and pioneering users that indicate that biodiesel and ethanol blends are most effective, with B20 (80% diesel) and E85 (15% gasoline) most commonly cited.

According to the National Biodiesel Board (NBB), “biodiesel blends operate in diesel engines, from light to heavy-duty, just like petroleum diesel. B20 works in any diesel engine with few or no modifications to the engine or the fuel system, and provides similar horsepower, torque, and mileage as diesel.”

NBB also points out that in its pure form or in blends, biodiesel can be stored wherever petroleum diesel is stored, except in concrete-lined tanks. The fuel should be stored in a clean, dry, dark environment. At higher blend levels, biodiesel may deteriorate natural rubber or polyurethane foam materials. “Biodiesel also has a higher flash point, handles like diesel and is safe to transport,” states the board.

Fuel quality, however, remains a concern for biodiesel users. Biodiesel that does not meet strict quality standards can clog filters and injectors and even increase emissions. NBB advises fleets to be sure they are purchasing biodiesel that meets the American Society of Testing and Materials (ASTM) Specification D 6751, which was released back in 2002. A copy of the D 6751 spec can be purchased for $35 at www.astm.org.

As for ethanol, the gasoline substitute, the American Coalition for Ethanol (ACE) makes similar claims for the straight gasoline substitute: “Ethanol is a clean, renewable, high-performance fuel… up to a 10% blend of ethanol (E10) is covered under warranty by every auto manufacturer that sells vehicles in the U.S. for every make and every model of vehicle. E85 (85% ethanol/15% gasoline) is for use in Flexible Fuel Vehicles (FFVs), which can operate on gasoline or any blend of ethanol up to 85%.”

ACE adds that since ethanol has a lower Btu value than gasoline, it “burns cooler and is gentler on the vehicle's engine — less wear and tear leads to longer engine life.”


The alternative fuel with the longest continuous track record in trucking is natural gas, in both its compressed (CNG) and liquefied (LNG) forms

Just because biodiesel and ethanol appear here to stay does not mean natural gas vehicles (NGVs) are going away. On the other hand, unless there are major technological breakthroughs to increase their range dramatically or a colossal nationwide effort to expand the fueling infrastructure, they'll remain a primary choice only for fleets that are centrally fueled at their own pumps or that have ready access to public fueling facilities.

Natural Gas Vehicles for America (NGVA) points to these key facts:

  • Over 150,000 NGVs now on U.S. roads

  • Over 1,500 NGV fueling stations in the U.S. — over half available for public use

  • Over 50 different manufacturers produce 150 models of light-, medium- and heavy-duty natural gas vehicles and engines

  • About 22% of all new transit bus orders are for NGVs.

The fundamentals of NGVs are fairly straightforward — they operate on the same basic principles as gasoline-powered vehicles. Fuel is mixed with air and fed into the cylinder where it is then ignited by a spark plug to move a piston up and down.

Natural gas can power the same vehicles currently powered by gasoline and diesel — be they light-, medium- or heavy-duty. But because natural gas is a gas rather than a liquid at standard pressure and temperature, some modifications are required for an NGV. These changes mainly involve the fuel storage tank, fueling receptacle/nozzle and the engine.

Most NGVs use CNG, which is stored onboard under high pressure in tube-shaped cylinders attached to the rear, top or undercarriage of the vehicle. These cylinders meet rigorous safety standards, states NGVA, and are made of high-strength materials designed to withstand impact and puncture. In the case of fire, they are fitted with pressure relief devices (PRDs) to provide a controlled venting of the gas rather than letting the pressure build up in the tank.

Natural gas can also be stored on board as LNG. NGVA points out that LNG requires only 30% of the space of CNG to store the same amount of energy. To keep it cold and thus liquefied, LNG is stored on board vehicles in thermal storage tanks — essentially “Thermos bottles.”

At CNG stations, explains NGVA, the gas is typically taken from a local gas utility's line at low pressure, compressed and then stored in the vehicle's storage tanks at high pressure.

Fueling equipment for CNG vehicles can be either “fast fill” or “time fill.” In fast fill, a large compressor coupled with a high-pressure storage tank (called a cascade) fills the tank in about the same amount of time it takes to fuel a gasoline or diesel vehicle.

With time fill, there is no storage system and a much smaller compressor, and vehicles are typically refueled overnight at a rate of about a gallon an hour.

NGVA points out that while LNG can be produced on site from available natural gas, it is typically delivered to a fueling station via tanker truck. Regardless, LNG is then stored onsite in special cryogenic storage tanks. To fuel vehicles, LNG is pumped into the vehicles much like other liquid fuels, although the cryogenic fueling equipment is technically more sophisticated.

There are also LCNG fueling stations. These use LNG to fuel both LNG and CNG vehicles. LNG vehicles are fueled as described and for CNG vehicles, the LNG is compressed as a liquid and then gasified. From there, the high-pressure gas is stored on the vehicle as at a fast-fill CNG station. Since it takes less energy to compress a liquid than a gas, once the LNG is available, LCNG stations are less expensive to operate, according to NGVA.


Hybrid is an unfortunate term that really does little to whet potential users' appetite for this promising fuel-saving and thus cost-saving and environmentally friendly technology.

The even uglier word hybridization refers to the efforts to develop electric and hydraulic drive-assist systems that supplement engines powered by diesel or gasoline — or their biofuel equivalents. At this point, hybrid powertrains may power anything from a car — famously the Toyota Prius — to a medium or heavy truck, or even reefer engines.

The neatest thing about hybrids is users can take full advantage of this technology without switching from fuels they already use or securing specialized vehicles or fueling infrastructure. They save fuel and cut emissions literally on the fly, as the vehicles they power go about their workaday business.

This off-the-shelf aspect of hybrids is helping them gain popularity in trucking. While utility truck fleets were early adopters and continue to be dedicated proponents of this technology, OEMs have responded notably. The list of truck makers that now offer hybrid power on at least some models or are running high-profile tests runs the gamut from the Dodge and Freightliner Sprinter to Workhorse Custom Chassis, Hino, International, Freightliner, Peterbilt and Autocar. Hybrid drive suppliers to the trucking industry include such familiar industry names at Eaton, ArvinMeritor and Parker Hannifin.

All such systems use a hydraulic or an electric drive to supplement the existing powerplant. These can be built in series or parallel setups. Series hybrids have the electric motor turn the vehicle's wheels while the IC engine provides power to charge the electric batteries. Parallel hybrids can be powered by the electric motor, IC engine or via some combination.

Also coming into play are so-called plug-in hybrids. DaimlerChrysler points out plug-in technology lends itself to commercial applications in which the vehicle returns to a domicile after each shift where it can be plugged into the power grid for recharging.


Down the road, fuel cell technology holds the most promise as a viable alternative for trucking and is the likely path to truly electric-powered vehicles. All-electric trucks are unlikely to be commercially viable due to the technological barrier of using an electric motor alone to propel such mass.

Michelin explains that fuel cells generate electrical current through a non-polluting electrochemical reaction that combines hydrogen, the most common element on the planet, and oxygen, producing mainly water and heat as its byproducts. And that is probably clean and green enough to satisfy even the most ardent environmentalist, not to mention all those in trucking seeking to burn less fuel.

According to Ballard Power Systems, a leading fuel cell developer, the technology for vehicles is still in a pre-commercial phase. The firm states it is working to drive down the cost of fuel cells so they become competitive with IC engines. “We expect to reduce the costs of fuel cells through volume production, system simplification and the use of lower cost components,” Ballard says.

OEMs involved in fuel cell vehicle development include DaimlerChrysler, Volvo and General Motors. The application getting the most attention so far is transit buses, but both UPS and FedEx have been involved in test programs for light delivery vehicles in the past several years.

How trucking will move beyond diesel is certainly not crystal clear, but what is clear is that fleet owners will have far more choices than could have been imagined just a few years ago.

And with that choice will come greater responsibility to pick the solution that best suits their fleet and best impacts their bottom line.


Location makes a difference

In August of 2002, the Arlington County, VA, municipal fleet converted one of its underground gasoline storage tanks to handle E85, the blend of 85% ethanol and 15% gasoline. For the next three years, the fleet ran over 100 “pickups, vans and sedans” on the high-blend alcohol fuel without incident, according to Rick Hiller, equipment bureau chief for the county. And then in the aftermath of Hurricane Katrina and the subsequent disruptions to gasoline supplies, the fleet ended its E85 program.

“We were using 26,000 to 30,000 gal. of E85 a year,” Hiller says. “We didn't have any problems with it other than the cost. But you lose some fuel mileage with E85 and in this part of the country it costs more than gasoline. So when Katrina created (gasoline) supply problems, we decided we needed the E85 storage tank for gasoline and we ended the program.”

Currently the fleet, which is committed to using alternative fuels where ever practical, is running all 700 of its gasoline-powered vehicles on E10, the commonly available gas blend that includes 10% ethanol. Since the county fleet consumes 600,000 gal. of gas a year, that 10% blend means it is currently using three times more ethanol than it did with its E85 program, according to Hiller. “And it's cost effective, especially with the prices we're paying now for gasoline,” he adds. “But as long as you kept water out of the [storage] tanks, E85 works well, and if the price ever comes down to the price of regular gasoline, I'd jump right back in again.”

That's what the city of Minneapolis thinks. In May it installed a new 6,000-gal. underground tank just for E85 and is currently running 200 light vehicles on the ethanol fuel.

“We had been using E10, but decided we needed a new tank for E85 rather than convert an older one” to avoid potential problems with incompatible seals and dispensers, says Bill Gauthier, maintenance manager for the Fleet Services Div., City of Minneapolis.

While E85's lower mileage means more frequent fill-ups for, the grains used to produce ethanol are grown all around Minnesota, which means E85 is actually cheaper than gasoline since it doesn't have to be transported long distances. “Even with lower mileage, it's just about break-even on cost,” says Gauthier. “And since we're an urban area, our MPG [with gasoline], was not so great to begin with. “

The real benefit with E85 comes from the “roughly 30% reduction in CO2 and other emissions,” Gauthier says. “Of course, (using E85) also supports the local economy, and there's a lot to be said for that. So far, the E85 performance has been flawless.”


Utility fleet jumps on B2O

As one of the largest utility providers in Tennessee and the Southeast, the Knoxville Utility Board (KUB) takes great pride in providing affordable, efficient, and reliable utility services to its customers. Much of its strength is attributable to its progressive fleet department.

David Forster, fleet supervisor for KUB, says: “We've implemented many technologies that have shown us to be a true pioneer within the field of fleet operations — especially utility fleets.” In 2000, for example, KUB launched a corporate-wide initiative to begin introducing various types of alternative fuels into its fleet vehicles. Today, all equipment — from aerial and bucket trucks to wastewater recycling vehicles — is run on some type of cleaner burning fuel.

“We started the conversions with our utility trucks, switching to a standard 20% biodiesel blend (B20). B20 is now used as an alternative fuel in all fleet equipment that was formerly diesel powered, including approximately 286 utility vehicles.”

According to Forster, there are over 900 pieces of equipment in the fleet, including 575 power units comprised mainly of International and Freightliner medium and heavy-duty chassis, as well as Chevrolet and Ford light trucks. Trailers, utility vans and apparatus, and construction equipment make up the remainder of the fleet.

The utility has been in operation as KUB since 1938. While it started out as an electric utility provider, the company has evolved over the years to include gas, water, and wastewater utility services as well. “There are some 434,000 customers currently using one or more of our utility services,” says Forster. “Amazingly enough, with all the diverse power equipment needed to support four different utilities, we have just one fleet department.”

This fall, Forster notes, KUB will be taking delivery of a brand new 2008 hybrid bucket truck, which is a joint-venture between Altec and International Truck & Engine Co. “There are only 24 of these trucks in use right now, and there will be only 75 to 100 of these vehicles produced next year,” he comments. “They run off a combination of B20 fuel, plus hybrid components. We're very fortunate to be one of just a few utilities around the country who will receive one of these hybrid trucks.”


One path to green

While utilities and other centrally fueled fleets have found natural gas to be a practical alternative fuel, that experience is not always replicated in other trucking operations. Giant package carrier United Parcel Service began extensively testing compressed natural gas (CNG) with its medium-duty delivery vans back in 1989 to assess the benefits and viability of CNG as an alternative fuel. In 2002, the company added liquefied natural gas (LNG) to its alternative fuel mix, powering 11 Class 8 tractors that haul two 28-ft. trailers each between its Ontario, CA, package distribution hub and Las Vegas.

While UPS found that natural gas initially produced far less pollution than similarly sized diesel-powered trucks, subsequent regulatory efforts to make diesel engines cleaner, coupled with a continued lack of refueling infrastructure, have made natural gas a less attractive alternative.

From a high of 1,700 CNG-powered trucks in 2004, UPS now only operates 700 in the U.S.

“Over the years, market forces … as well as the development of new and better alternative fuel technologies have led to reduced infrastructure support for CNG technology,” the company explained in its latest “Corporate Sustainability” report. “As a result, when our U.S. CNG vehicles are retired, they are being replaced with new diesel vehicles that are more fuel-efficient and produce fewer emissions.”

LNG is very dense, providing a large amount of energy for the amount of space it occupies, thus making it an excellent fuel for large trucks that need to travel a long distance before refueling, the company's report notes. However, the higher sticker price for these LNG-powered rigs will probably curtail further investments in the future by the company.

On average, LNG tractors cost $35,000 to $40,000 more than comparable diesel-fueled models, according to UPS. One reason for the higher cost is that LNG yields slightly more than half the fuel economy of diesel, so its tractors are fitted with auxiliary tanks to boost fuel capacity by about 50%, enabling them to go 600 miles before refueling.

There are some cost savings, however. The company's LNG tractor engines use a small amount of diesel fuel while using LNG as the primary fuel source, thus eliminating the need for spark plugs. Since the engine's oil needs to be changed less often, maintenance costs are lower.


Shrinking their footprint

Pepco Holdings Inc. (PHI) operates a fleet of 2,000 vehicles in Washington, DC, Maryland, Delaware and New Jersey. Early this spring, the company announced an ambitious plan to reduce its carbon dioxide “footprint” by implementing a number of measures designed to reduce emissions and conserve fuel, including adding hybrid vehicles to the fleet and switching from diesel to B20 biodiesel for all its diesel-powered vehicles.

Today, PHI has 32 hybrids in service and is pumping B20 at all its fueling sites, according to Frank Cottone, group manager for vehicle resource management at PHI. “We have some hybrid cars, including the Toyota Prius and Highlander and the Ford Escape,” Cottone says, “plus one 42-foot, diesel-electric hybrid bucket truck. The truck [manufactured by International] is part of a pilot project with Eaton Corp.”

The pilot has been a big success, too, Cottone notes, so much so that eight more hybrid trucks are in the budget for 2008. “We have been very pleased with the performance of the hybrid truck,” he says. “We are working with the EPA to track key-on/engine-off hours in order to measure our fuel savings and emissions reductions and the improvements in both areas have been significant.”

This hybrid even saves fuel when the truck is parked, according to Cottone. “We can operate the boom for a while in the hybrid mode,” he explains. “That means we don't have to idle the truck's engine to raise the bucket. The result is lower emissions, less noise and lower fuel costs.

“We have also actually interviewed the driver and he is enthusiastic about the hybrid truck's handling and performance,” Cottone adds. “When the vehicle switches from electrical power in the hybrid mode to the truck's engine, for example, the driver says there is absolutely no shifting of the bucket. That is extremely important to us from a safety standpoint.”

PHI plans to continue to evaluate hybrids, renewable fuels and other technologies to increase the number of alternatively powered vehicles in its fleet, according to company spokesperson Robert Dobkin. “This is becoming the way to do business,” he observes. “It is very clear that this is what our customers want and expect from us.”

In addition to their own environmental initiatives, PHI is also working to help their nearly two million customers reduce their own electricity usage with a number of new programs and incentives.

View more Fleet Owner news relating to alternative fuels, hybrid technologies, fuel conservation and diesel fuel prices.

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