The U.S. Postal Service (USPS) Washington, D.C., Network Distribution Center (NDC) previously used lead-acid batteries in its powered industrial vehicle (PIV) fleet. The batteries were costly to maintain, short-lived, and posed environmental risks.
Charging and changing lead-acid batteries also posed significant challenges: The vehicle operator had to leave his or her work assignment, go to the battery room, wait for a battery change and then return to work. On average, this process took 20 minutes and resulted in about 96 hours of lost productivity per day.
Each vehicle also required three batteries—one battery in the vehicle, one battery charging and one battery cooling down after charging. In addition, lead-acid batteries have compliance costs associated with their use and also require a great deal of energy to charge.
USPS leadership initiated a Lean Six Sigma review project to find more productive ways to address the challenges. Hydrogen fuel cell technology quickly emerged as a fitting potential solution, and the NDC began a pilot of the technology.
During the pilot program, the NDC PIV inventory was decreased to 85 vehicles from 92 because older PIVs were not compatible with hydrogen fuel cells. The NDC facility was modified with the installation of permanent hydrogen production, storage, and dispensing equipment.
The NDC overcame many hurdles while implementing this pilot, including:
- Older vehicles not being compatible with the new fuel cells. The older vehicles required 22 to 26 volts, which was lower than the voltage output of hydrogen fuel cells.
- A defective circuit board. Discovered after implementation, this defect in the fuel cells caused a complete loss of power.
- Problems with braking. Newer vehicles, which were equipped with an e-brake system, were able to stop the vehicle from rolling away when the battery was completely discharged, but the older vehicles had a mechanical brake.
These issues were fixed by redesigning the electrical system and installing new brake kits on affected vehicles, but they resulted in a 120-day delay. Among the lessons learned from this pilot project, the NDC recommends laying out hydrogen operations and processes fully to ensure efficient and safe operations.
Because of the pilot program’s success, USPS is considering evaluating the scalability of this technology.
In the meantime, the NDC team recommends the following for those considering adopting this technology and process.
- Upgrade PIVs from lead-acid batteries to hydrogen fuel cells is most effective when a facility has more than 50 pieces of equipment with high operational cadence.
- Include a First Article Test or Inspection in the fuel cell procurement process before attempting a full fleet upgrade.
- Invite the local fire department to initial employee training sessions to ease employee safety concerns.
- Plan a refresher training soon after the initial training. Once employees have actually used the fuel cells, they may have additional questions that were not considered during the first training session.
- Procure fuel dispensers from the same vendor as the fuel cells, as the dispensers may be more compatible with the fuel cells, and more data may be easily captured and automated.