day’s observation at an airfield inspired a food supply-chain expert to marshal
engineering muscle behind fast-charge technology for lift trucks.
A. Lewis, energy & supply chain management advisor, University of
California-Davis and president, Glen Lewis Group, Elk Grove, CA
the automotive industry, fast-charge battery systems are the new standard for
powering material-handling equipment. The change had its genesis in the food
industry, however, and the transition occurred in a remarkably short period of
time. The technology was adapted from the aerospace arena, and collaborative
engineering was necessary to create an integrated system. The transition was
driven largely by one individual working outside the typical structures of an
Glen A. Lewis, former director of energy and indirect procurement for Del Monte
Foods, encountered fast-charge technology five years ago and saw it as a way to
enhance the company’s competitive position while also improving enterprise
energy management (EEM) and enterprise asset management (EAM). The effort
became a springboard for a US Department of Energy Best Practices demonstration
project that treats water, gas, electricity and other forms of energy as assets
to be managed and optimized, just as equipment lifecycles and working capital
are optimized. That project was recognized by the state of California with an energy education
and leadership award.
Lewis did undergraduate work in aeronautical engineering and political science
at UCLA and received an MBA from the College
of William & Mary. He held
management positions in operations, engineering and other areas over a quarter
century in the paper-and-pulp industry and at Del Monte Corp. Lewis also leads
an integrated enterprise energy/asset management effort for Gov. Arnold
Schwarzenegger’s Green Action Team. He left Del Monte Foods in February and
formed the Glen Lewis Group, an Elk Grove, CA-based consultancy.
stations resembling gas pumps quickly replenish AC batteries during scheduled
downtime and eliminate the need for swapping DC batteries. Source: PosiCharge
System Group, AeroVironment Inc.
When did you first encounter fast-charge systems?
Lewis: To get ideas on how we could optimize asset utilization at Del Monte, I
benchmarked American Airlines’ flight-line operations at Dallas-Fort Worth
Airport in 2002. American can’t afford to have aircraft assets idle, and
overall equipment effectiveness of ground support is critical.
One of the technologies I saw were fast-charge stations for ground-support equipment.
The convention in food is to use DC batteries for forklifts in distribution
centers and propane-powered internal-combustion forklifts in the plants. Fast
charge had the potential to reduce operating and maintenance costs, increase
asset utilization and extend operating life.
FE: What development work was necessary before bringing the technology to the
Lewis: American Airlines’ charging stations were built by AeroVironment’s
Posi-Charge division. The batteries were manufactured by EnerSys, a leader in
material-handling battery applications. I worked with those firms and with Yale
to develop new AC-powered forklift technologies. I also secured a grant from
the Electric Power Research Institute to evaluate not only operating costs in a
food processing facility but also the impact on power demand and the power grid
if fast charging becomes widespread. Visibility, metrics and knowledge are
needed to turn EEM and EAM from a black box to a glass box.
The charging technology actually had its genesis in the 1990s, when the
California Air Resource Board was promoting electric cars. AeroVironment
developed Posi-Charge to function as service stations for on-road vehicles.
When the electric-car initiative collapsed in 1998, a new market had to be
FE: Was it simply a matter of bundling equipment already available from those
Lewis: Rather than view this as various pieces of vendor equipment, we mapped
out a strategy and took a team approach to develop an efficient system. The
process of charging is the same, but the equipment is different, and the
environment is more intensive than an airfield. The three key vendors
collaborated to take material handling to the next level. You have to be sure
that it works before you take it into a plant, where the rubber meets the road.
FE: What did you learn in the EPRI funded project?
Lewis: The EPRI grant helped quantify the economics and develop a roadmap for
implementation. We also built what I called a lab-rat charger to demonstrate
the technology. The subsequent report was published three years ago. Among the
findings was that a fast charger can charge a battery three to six times faster
than a conventional unit. In a three-shift operation, operational costs for the
battery can be 20-25% less than for conventional batteries. We also recommended
staggered recharging to lower electrical demand charges.
FE: How was the technology deployed at Del Monte?
Lewis: We initially set out to convert distribution centers, where electric
forklifts already were used. As with any change-management endeavor, the people
at some facilities are going to be more receptive to change than others, so you
partner with them first.
Because the manufacturing sites used internal-combustion forklifts, expanding
the technology to the plants was a bigger challenge. Noise equates with power,
and there is the perception that electrically powered lifts have less power.
The first step was to put the technologies head to head and dispel that myth.
I videotaped and interviewed the drivers in the early trials. One of the first
things a driver of a propane forklift would say is, “I’m not breathing fumes
when I’m driving backward now.” What are the work-loss days from pulmonary
disease caused by breathing fumes? It’s a hazardous material, and you can’t
store anything within 75 ft. of propane. By converting to electricity,
insurance premiums are reduced, and non-value-added space is eliminated. Up to
22,000 sq. ft. were freed by taking out propane tanks at some facilities.
Additionally, maintenance costs for AC forklifts are 60-80% lower than with
From my days at UCLA, one John Wooden “Woodenism” that stuck with me is, “It’s
what we learn after we know it all that counts.” You have to be open-minded
when you approach a new way of doing things, and the safety and operation of AC
forklifts is an example. Less noise is a good thing, but people are used to
hearing forklifts and reacting to them. When you reduce decibel levels, drivers
have to be retrained to use convex mirrors, honk their horns more often and use
FE: How does fast-charge compare to DC-powered lift-trucks?
Lewis: A key savings is in eliminating battery changes. Our time studies
indicated it takes 15-20 minutes to change a battery. Over three shifts, that’s
almost an hour of lost productivity per day, per truck. There are several
thousand forklifts at Del Monte. The potential to reduce the size of the fleet
or realize incremental shipping advantages is significant.
In a 24/7 scenario, a plant needs three 48-volt DC batteries. Batteries are
changed at the end of each shift, which requires a hoist and adds the potential
of personal injury. Batteries are recharging constantly, both at peak and off-peak
hours, which increases energy costs and the facility’s carbon footprint and
adds pressure on the electrical infrastructure in growing communities. DC
batteries cost $5,000, so plants realize a $10,000 savings simply by buying two
fewer batteries per truck.
With DC, batteries gradually lose power over a shift. Horizontal and vertical
speeds decline, reducing productivity and increasing maintenance. With AC,
voltage is constant until the supply is totally discharged. That means less
mechanical stress on the equipment. Recharging can be shifted to nonpeak hours,
with complete elimination between 11
and 6 p.m. during peak demand.
Compared to AC, DC forklifts are analogous to a typewriter in a Pentium world.