June 1, 2008
technology review | Fuel Cell Technology

All charged up

all charged up

Eager to see how its newly developed fuel cell device would fare in trials, East Penn Manufacturing decided to test the unit itself. But round-the-clock DC operations and 4,000-pound loads would make this a rigorous trial.

By James A. Cooke

When it came time to begin testing its prototype hydrogen fuel pack for lift trucks, East Penn Manufacturing didn't have to look far for a beta tester. With a 180,000-square-foot distribution center operating 24 hours a day, the company already had an ideal test lab. Why not test the device itself?

And so, for the past two-plus years, the company has been using eight forklift trucks powered by the device, a hybrid fuel cell/lead-acid battery unit, at its DC in Topton, Pa. The trucks work alongside their 20 battery-powered counterparts at the cavernous facility, which operates around the clock five days a week. As tractor-trailers from the plants arrive at the DC, the forklifts offload pallets of batteries and place them in storage. They also ferry pallets from storage to the loading-dock area when needed. Shuttling pallet loads of batteries is no small task; the loaded skids weigh between 3,500 and 4,000 pounds apiece on average.

Best known for its Deka brand batteries, East Penn Manufacturing Co. Inc. makes batteries and accessories for the automotive, marine, farm equipment, and industrial truck markets. Though a DC operated by a leading battery maker might seem an unlikely proving ground for fuel cells—after all, fuel cells might soon be competing with batteries in the motive power market—East Penn doesn't see the cells as a threat. In fact, it sees them as a potential addition to its product line.

East Penn is not working on the fuel cell project alone, however. In December 2004, the Lyon Station, Pa.-based company began discussions with Nuvera Fuel Cells of Billerica, Mass., about developing a fuel cell-based unit for electric lift trucks. The result of their collaboration is the ReadyPower, a hybrid device that combines Nuvera's fuel cell technology with East Penn's lead-acid battery design. The two companies eventually hope to make the device available commercially.

Before it can begin selling the ReadyPower to customers, however, East Penn first needs proof of concept. Testing the unit on its own lift trucks has given the battery maker a way to validate the concept as well as work out any bugs. "We want this operation to be as seamless as possible for our customers' operations," says Jim Rubright, East Penn's vice president of motive power sales and the executive in charge of the fuel cell project. "They don't have time to experiment with new technology. They need to know it will work and work well, and we plan on proving that to them by using it in our own operation."

Getting the lead out
Although the use of fuel cells to power vehicles is still in the developmental stages, the technology itself is nothing new. First developed in the 19th century, fuel cells later were made famous when the National Aeronautics and Space Administration used fuel cells to supply electricity and water on manned space flights.

Hydrogen fuel cells like the ones used in the ReadyPower units use hydrogen and oxygen to produce electricity. The only byproducts are water and heat, which makes them an environmentally friendly power source. Fuel cells differ from batteries in that they consume reactant (hydrogen), which must be replenished, whereas batteries store energy chemically. The ReadyPower unit consists of a fuel cell stack and a set of "peaking batteries" to provide auxiliary power. The peaking batteries are sealed absorbed glass mat (AGM) units that require no maintenance.

In operation, the fuel cell provides a regular supply of electric power to operate the vehicle and, at the same time, recharge the peaking batteries on board the truck. If the truck needs extra power to, say, lift a heavy load, the unit draws on the batteries for the extra oomph. "If the truck needs more power than the fuel cell can provide, the batteries kick in," explains Rubright.

The ReadyPower unit also contains a tank filled with compressed hydrogen gas. Although the size of the tank may vary, all tanks hold at least 0.6 kilograms of hydrogen. During its trials, East Penn has been experimenting with different sized hydrogen tanks and peaking batteries. (The fuel cell stack, by contrast, has remained a constant size in all models—14.6 by 17.3 by 20.7 inches.) A control panel is plugged into the ReadyPower unit and mounted on the lift truck to let the operator know when his fuel tank is empty.

The ReadyPower unit itself was engineered to be easily interchangeable with a lead-acid battery. "Our design is basically plug and play," Rubright says. "We can pull a lead-acid battery out and put a ReadyPower in its place if we want to, with no modifications to the truck."

Rubright reports that one of the challenges in designing the ReadyPower unit was handling the disposal of the water generated by the system. After some experimentation, East Penn came up with a mechanism for water evaporation as well as reuse. "In some other systems, you have to empty a [water] collection tank," he explains. "Ours is a water-neutral system."

In the design process, East Penn also had to address counterbalance issues— that is, keeping weight distributed evenly in order to prevent the truck from tipping over. The ReadyPower unit meets the same center-of-gravity and counterweight requirements as the lead-acid battery it is replacing.

Rubright reports that the ReadyPower unit has undergone constant tweaking during the last two years of testing. "We've subjected our unit to shock and vibration testing," he says. "And we've [made] a lot of improvements."

Consistent performers
As for the hybrid units' performance, the forklift drivers report several advantages to using the ReadyPower unit over traditional lead-acid batteries. For instance, the hybrids eliminate the need for operators to drive over to a special charging area at the end of a shift and remove a 3,000-pound battery for recharging. Instead, the drivers pull the truck up to a dispenser and refuel the unit with liquid hydrogen. Refueling takes just 30 to 90 seconds. "The operators love it," says Rubright. "And you no longer have to maintain a battery room with charging equipment."

The operators also report that the trucks using the ReadyPower units run "crisp." As Rubright explains, they're referring to the hybrid unit's ability to deliver a steady supply of power throughout the shift, in contrast to the traditional battery, whose voltage drops as the day wears on, making the truck sluggish. "As long as you have hydrogen in the [ReadyPower's] tank," he says, "the truck operates as if it's on a freshly charged battery all day long."

Rubright suspects that the elimination of "voltage lag" has led to increased productivity within the distribution center. In future tests he hopes to be able to demonstrate that operators on ReadyPower-equipped trucks move more pallets per day than their counterparts on traditional trucks do.

A chicken-egg dilemma
Although the beta ReadyPower units have shown considerable promise in testing, the technology still faces some obstacles to widespread adoption. For starters, a distribution facility using this technology needs storage tanks of hydrogen fuel on site. A company could purchase hydrogen from a commercial gas dealer or generate it from natural gas. East Penn plans to offer customers a "Total Power Solution" that provides on-site hydrogen generation, storage, and dispensing abilities.

In its own operation, the company has been producing hydrogen from natural gas at its site through the process of steam reforming. In that process, natural gas (mostly methane) is combined with steam over a catalyst bed to produce hydrogen. "There's a significant advantage to generating your own hydrogen," says Rubright. "The cost per kilogram for generating your own hydrogen can be half to two-thirds the cost of what you buy."

But the main obstacle to wider deployment of this technology remains price. "The industry knows we have to bring the cost down," says Rubright, who declined to give specifics on the actual cost of a ReadyPower unit. "It's the old chicken and egg thing. You have to have economies of scale [to bring down the cost], and at the same time, you're trying to get the technology out there in the market [to develop the needed scale]." He acknowledges that the technology may never be economical for light-duty or short-shift applications.

As for the next step, East Penn is now preparing to expand its pilot beyond its own four walls. Rubright reports that the company has lined up customers to deploy beta ReadyPower units in their own lift trucks later this year.

With more companies signing on to use the hybrid technology, is East Penn worried about the effects on its battery sales? Rubright dismisses that concern. He believes that the traditional lead-acid battery units will continue to be sold alongside units like the ReadyPower. "We envision this as one of the solutions in the bag," he says. "Whatever works best for the customer is what we want to recommend."

Editor's note: To read more about the use of fuel cells to power industrial trucks, see our June 2007 story "fuel cells get hotter."

About the Author

James A. Cooke
James Cooke is a principal analyst with Nucleus Research in Boston, covering supply chain planning software. He was previously the editor of CSCMP’s Supply Chain Quarterly and a staff writer for DC Velocity.

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