Fuel: Diesel & Beyond

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.

ONE PLUS ONE

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.

MORE TO COME

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.

ETHANOL

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.”
— JIM MELE

BIODIESEL

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.”
— DEBORAH MCGUFFIE-SCHYHOL

NATURAL GAS

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.
— SEAN KILCARR

HYBRIDS

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.
— WENDY LEAVITT

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