As an airport contractor, ACE Parking had some influence to switch its vehicle from diesel to a cleaner alternative fuel. The options included CNG and propane autogas. ACE first tried CNG. After running its shuttle fleet on CNG for several years, ACE began to implement its propane initiative.

“The company decided to switch to propane because of the cost savings and the ease of access overall,” says Kevin Hernandez, managing director of ACE Parking’s ground transportation division.

In the last month, the average cost per gallon for propane autogas is $1.97 compared to $2.44 per gallon for CNG. For ACE Parking’s 29 vehicles at San Diego International Airport, that translates to a fuel cost savings of $12,000 per month.

In San Diego, ACE Parking has 29 shuttles operating specifically at its airport lots and an additional 30 vehicles across the county, according to Hernandez.

The fleet consists of Ford F-550 Starcraft and Ford E-450 Champion Challenger shuttles. The nine F-550 Starcraft shuttles (a F-550 chassis with a Starcraft-manufactured body) operate only at the airport lots. Built on the E-Series cutaway chassis with a Champion Challenger body, the 50 E-450 shuttles range from 2010 to 2016 model-years.

ACE Parking’s airport shuttles average between 36,000 and 40,000 miles per year, says Hernandez.

On-Site Refueling

In addition to cost savings, another advantage for using propane vehicles is easier access to a refueling station.

At San Diego Airport, there is no private CNG refueling depot available. According to Hernandez, ACE’s CNG shuttles had to refuel at the closest public CNG station — about three miles away.

“It was difficult because the station is in a small area,” says Hernandez. “The Clean Energy pumps are located at a Shell station. It would get very busy and it was first come, first serve. Plus, the tight-turning area in the station meant a higher risk of getting into an accident.”

After learning more about ROUSH CleanTech’s propane technology, ACE’s next step was figuring out how to get propane autogas on-site at its airport location. Partnering with propane provider Expo Propane, ACE brought airport officials a proposal to install on-site propane refueling stations.

“The airport bought in and allowed us to put in our own propane filling stations on-site,” says Hernandez. “Expo Propane paid for all the infrastructure and designed it. They did the training, too.”

Once the refueling tanks were installed, ACE Parking started acquiring its new shuttle vans. After ACE purchases a Ford chassis, ROUSH installs the propane autogas unit. Then the shuttle body is put on the chassis.

Out of ACE’s 59 fleet vehicles, 55 are currently running on propane. Hernandez expects that the remaining four CNG vehicles will be switched out for propane within the next year.

Maintaining Vehicles

Around 150,000 miles, ACE starts making decisions on what to do with the fleet vehicle: What is the condition of the engine, transmission, body, and frame? Should it be kept or sold?

“If everything checks out during a maintenance check, then we start looking for a different contract within our company to move the unit,” says Hernandez.

On the other hand, if the shuttles need major maintenance work, ACE will start to liquidate them either by selling outright or at an auction.

With its shuttles on the road between 20 and 21 hours per day, preventive maintenance is very important to the company, says Hernandez.

As an airport contractor, ACE partners with Penske. Each of its vehicles goes through Penske’s preventive maintenance program, which includes oil changes and tire changes.

“So far, performance-wise we haven’t been able to tell the difference between the propane and CNG vehicles,” says Hernandez. “As far as ease of access and the fuel itself, it has been a pretty easy transition to propane.”