CNG has been holding its own as a popular alternative fuel choice for city fleets. In order to keep city vehicles running smoothly on CNG while also saving money in the long run, many cities are investing in CNG stations, often working with private entities or other local jurisdictions to do so. In October 2016, for example, the city council of Olathe, Kan., approved a $3.3 million CNG station that will be built at its public works facility. The city will pay two-thirds of the construction cost, with Johnson County, which is partnering with the city, paying the rest. Olathe also plans to pay $525,000 for station equipment, using state grants. Actual construction was expected to begin in February of this year and will benefit the growing fleets of both Olathe and Johnson County.
With the sheer size of investment that goes into a CNG station, fleet managers will undoubtedly want to keep them in shipshape, especially since a well-maintained station can prolong the lifespan of fleet vehicles.
John Colby, ZJT Consulting, IT director for the city of Milton, Fla., a city of approximately 9,323, shared some information about his city’s CNG station.
“The CNG station at the City of Milton is open 24/7 with (credit card payments) — Visa/ MasterCard/Discover, plus the fleet card,” Colby said, adding that the cost of CNG fuel is $1.95 per gallon.
“Note that this is the equivalent of a gallon (of gas) that now is $2.45 per gallon on average, so yes, it’s cheaper.
“The city has two compressors at the site that compresses natural gas into compressed natural gas and dispenses it 3,200 pounds per square inch and 3,600 psi. We also have bottled CNG for older vehicles that need a lower pressure.”
As for maintaining the station, said Colby, the only challenges they have are the same that normal gas stations have. “That includes equipment failures, electrical breaker resets and so on. We maintain the equipment and have to occasionally call repair folks to repair the gear.”
Bill Davis, director of National Alternative Fuels Training Consortium in West Virginia, agreed.
“Some of the same things you would do for any fueling station, including checking the equipment and doing necessary maintenance at the CNG locations,” Davis said.
“First, you have to do preventative maintenance on your equipment. Pay attention to whatever the manufacturer calls for, but especially cleaning and draining filters, lubing valves when necessary, changing desiccant for the system, checking oil in the compressor, keeping your dispensing station prepared and doing the required inspections per codes and regulations,” he added.
On the West Coast, the city of Covina, Calif., made the investment in a CNG station in 1993, with the station being constructed using grant funds from the South Coast Air Quality Management District’s Assembly Bill 2766 Subvention Funds; it became the first cityowned CNG station in its region. Upgrades, however, became a necessity to modernize it since its construction.
According to the city’s website, this upgrade included “a new compressor and storage vessel and the addition of a new 3,600 psi fueling dispenser that will allow station users with a 3,600 psi tank to obtain a 100 percent fill during fueling.” The new equipment made it possible to provide newer vehicles with a full fill. The current fueling dispenser that fills 3,000 psi was kept to accommodate “legacy station users” who have older vehicles with 3,000 psi tanks, at least until their tanks expire.
Overall the project cost approximately $666,200, with funding coming from AB 2,766 and Mobile Source Air Pollution Reduction Review Committee, which offered matching grant funds. The balance was borrowed from the city’s equipment fund and will be repaid from yearly AB 2,766 grant receipts.
CNG stations are as safe as any fueling station, Davis said, but they are different and employees need to understand the differences if they are working with them.
“They are not ‘bombs’ as some old myths led people to believe,” he said. “There have been no explosions of CNG stations or serious incidents with them. They are safer when fueling than using gasoline or diesel as they are a closed system, and you do not have the fumes emanating from the gas tank.”
Most of the CNG stations Davis has had experience with are open continuously. They have both public and private stations in the area that are open around the clock, and most of them have control units that refill the storage array as it depletes.
“In some cases, because of how refueling takes place, fleet stations may schedule their filling of vehicles and then replenishment of the storage array,” said Davis.
For information and case studies on CNG and other alternative fuels, visit the U.S. Department of Energy’s Alternative Fuels Data Center at http://www.afdc.energy.gov/case.