According to the DOE, propane autogas' high octane rating (104 to 112, compared to 87 to 92 for gasoline) and its cleaner-burning characteristics result in documented engine life up to two times that of gasoline engines. 
 -  Photo: Alliance Autogas

According to the DOE, propane autogas' high octane rating (104 to 112, compared to 87 to 92 for gasoline) and its cleaner-burning characteristics result in documented engine life up to two times that of gasoline engines.

Photo: Alliance Autogas

When the City of Fort Worth, Texas, implemented its alternative-fuel program in 1995 to comply with the 1990 Amendments to the Clean Air Act, the City selected propane autogas because of the fuel's high-mileage range, as well as low infrastructure and operating costs.

Today, the City of Fort Worth operates more than 175 vehicles fueled by propane autogas, the majority of which are Ford F-150 pickups, comprising approximately 5 percent of the City's 3,200-vehicle fleet.

With more than 15 years of operating and maintaining propane autogas vehicles, what's the City's verdict?

"Overall perceptions of propane autogas are good," said Wayne Corum, director of equipment services for the City of Fort Worth. "The biggest challenge is getting operations departments to accept any alternative fuel. The acceptance comes once all of the concerns about vehicle operations are addressed, including power, fueling, and vehicle performance."

Acceptance doesn't seem to be an issue with the City, which has 10 more propane-autogas fueled vehicles on order for 2012.

"We'll continue to add more propane autogas vehicles because there is cost savings in the right application," Corum explained.

The City of Fort Worth is just one of a growing number of public and private fleets making the conversion, including Frito-Lay of North America, ThyssenKrupp Elevator, and American Residential Services.

What exactly is propane autogas? What are the advantages? What's involved with the conversion process? What factors should fleet managers consider before making the switch?

Propane Autogas Defined

Used in vehicles since the 1920s, propane autogas, also known as liquefied petroleum gas (LPG), is the world's third-most common vehicle fuel, behind gasoline and diesel, powering more than 17 million vehicles worldwide.

Listed as an approved alternative fuel under the 1990 Amendments to the Clean Air Act and National Energy Policy Act of 1992, propane autogas is a byproduct of natural gas and petroleum, occurring naturally during oil refining and natural gas processing. The key difference between autogas and vehicular natural gas - whether compressed natural gas (CNG) or liquefied natural gas (LNG) - is the chemical make-up. Although both are hydrocarbon fuels, propane autogas is comprised primarily of propane and butane, while vehicular natural gas consists mostly of methane.  

Most propane autogas vehicles are gasoline-powered vehicles that have been converted to operate using the alternative fuel. Dedicated propane vehicles run exclusively on autogas, while bi-fuel vehicles offer two separate fueling systems that allow the driver to switch between propane autogas and gasoline.  

Propane Advantages

Proponents cite a number of reasons why fleets should switch to propane autogas. The main advantages include:

Homegrown fuel. According to Brian Carney, director of marketing for ROUSH CleanTech, a supplier of dedicated propane-autogas systems for light- and medium-duty trucks, the U.S. is a net exporter of propane, on the scale of 1.5-2 billion gallons per year, with 97 percent of the propane used today coming from North American sources. This translates into increased U.S. energy security, say supporters.

"I like to imagine two barges passing each other on the ocean, one coming from the Middle East on the way to the U.S. carrying crude oil, the other coming from the U.S. on its way to South America full of propane," Carney said. "One is dirtier, more expensive, and sold to us by countries that don't much care for us. The other is clean, cheap, and domestically produced, yet we're shipping it away and buying the other stuff. That doesn't have to be."

Environmental benefits. Propane autogas is touted as one of the cleanest burning of all fossil fuels. According to the Propane Education & Research Council (PERC), tests conducted by the U.S. Environmental Protection Agency show that propane-fueled vehicles produce 30- to 90-percent less carbon monoxide and about 50-percent fewer toxins and other smog-producing emissions than gasoline engines.

Lower maintenance cost and increased engine longevity. The cleaner-burning aspect of autogas protects more than the environment. According to the U.S. Department of Energy's Alternative Fuels and Data Center, propane autogas' high octane rating (104 to 112, compared to 87 to 92 for gasoline) and its cleaner-burning characteristics (low carbon and oil contamination) have resulted in documented engine life of up to two times that of gasoline engines.

Although Carney of ROUSH CleanTech is cautious about recommending longer maintenance intervals for propane-autogas-fueled vehicles, he offered this comment: "As the technology provider for propane-autogas vehicles, we always recommend the same maintenance intervals and schedule the OEM does. That being said, some of our fleet customers conduct oil analyses to determine when the appropriate time for oil changes comes up. A number of our customers using full-synthetic oil report back that they can double their mileage between oil changes due to the cleaner-burning nature of propane autogas. That's not our recommendation, but they have the data to support it and are able to cut oil change costs in half using that data."

Gary Kulp, president of Austin Gutter King, concurred. His company operates four trucks fueled by propane autogas, three Ford F-150 pickups and a Ford E-350 cutaway van, comprising 25 percent of his service fleet. "Propane autogas burns so much cleaner, so we don't have to change the oil very often. We expect the engines to last twice as long because there are fewer hydrocarbons; we're expecting to get about 300,000 miles out of these engines."

As a result of the performance of his existing propane-autogas-fueled trucks, Kulp intends to convert his entire fleet over the next three to four years "as our fleet ages and we buy more vehicles."

Lower fuel price. Carney noted, "Generally, a fleet can purchase one gallon of propane autogas for up to 40-percent less than a gallon of gasoline. This has a dramatic effect on lowering the operating cost of fleet vehicles."

According to the most recent Clean City's Alternative-Fuel Price Report, propane autogas offers $0.86 per gallon savings compared to diesel.

Tax incentives. Fleet managers can also see cost savings through use of various tax credits and incentives available for alternative-fueled vehicles, including propane autogas. These tax breaks help defray the incremental cost of converting vehicles to run on propane, making it a more financially viable alternative to conventional fuels.

Conversion Process

Converting a vehicle to run on propane autogas typically involves installing a new fuel tank, fuel lines, fuel rail, and fuel injectors. The OEM's onboard PCM (powertrain control module) will most likely need to be reprogrammed to ensure the vehicle runs properly on propane autogas.

"We also recommend new-vehicle buyers purchase a vehicle equipped with Ford's gaseous fuels prep package, which contains hardened valves and seats in the engine. It's an inexpensive factory-option from Ford," Carney advised, referring to ROUSH CleanTech's conversion systems for Ford light- and medium-duty trucks. "This ensures no premature wear happens when burning propane or other gaseous fuels, which tend to have less lubricity than gasoline or diesel. It also ensures that the vehicle is covered under the same warranty that it would be were it to stay operating on gasoline."

While the fuel tank (for dedicated propane autogas systems) is designed to go in place of the gasoline tank, conversion suppliers typically offer an "extended-range" tank option that allows for greater fuel capacity, in exchange for less cargo space. For pickup trucks, this option would be an in-bed fuel tank. In cargo and passenger vans, the extended-range fuel tank is installed inside the vehicle (often where the last row of seats would go in a passenger van).

Kulp with Austin Gutter King equips his pickups with an extended-range 60-gallon tank and has been pleased with the performance.

Austin Gutter King operates four trucks fueled by propane autogas, comprising 25 percent of his service fleet. 
 -  Photo: Roush CleanTech

Austin Gutter King operates four trucks fueled by propane autogas, comprising 25 percent of his service fleet.

Photo: Roush CleanTech

"I like [the in-bed propane tank] because it moves weight forward [in front of the rear axle], allowing me to tow more because I no longer have the weight of a 35-gallon gas tank at the rear of the vehicle," Kulp explained. "I also drive quite a bit, but I only fuel the truck once a week, which is half as frequently as I would fill up with a gasoline vehicle.

Conversion Cost

The U.S. Department of Energy's Alternative Fuels and Advanced Data Center estimates the cost to convert a light-duty vehicle in the range of $4,000 to $12,000.

"Typically you're looking at a $10,000 incremental cost or more to convert a light-duty truck or van to propane autogas," Carney said. "That price rises as you go up in GVWR, typically driven by tank size, fuel line length, and complexity of the system."

The Business Case

How do fleet managers justify the added upfront cost to convert vehicles to run on propane autogas? Is there a compelling enough business case for fleet managers to take the risk and make the switch?

"I always go back to the fuel-cost side of things when talking about price," Carney explained. "If you're just going to compare your 'day one' cost to own the vehicle, propane autogas is always more expensive than gasoline. What you have to take into account and ask yourself is, 'What is it going to cost me to operate this vehicle over the 150,000- or 200,000-mile lifecycle before I get rid of it?' When you look at fuel prices of $3.60-plus per gallon for gasoline and compare it to $2.18 for propane (without even subtracting the $0.50 per gallon tax credit from that propane price), you can see that the incremental cost will easily result in a positive return on investment for that vehicle by the time it's ready to be retired."

What fleet applications present the best fit for propane autogas-fueled trucks to generate an acceptable return on investment?

"Our propane autogas trucks are used for light- to medium-duty work truck applications, such as field vehicles for inspectors, supervisors, crew trucks, and for the utility and public works departments," Corum said, referring the City of Fort Worth's fleet. "These vehicles tend to be high-mileage vehicles driven throughout the city on a daily basis, so the economy of scale is favorable. Propane autogas technology was developed for this kind of high-mileage usage."

The key question fleet managers should ask: Will the truck travel a sufficient number of miles, within an acceptable time frame, to recoup the cost of propane conversion and generate an acceptable return on investment?

Fueling Infrastructure

The propane industry has worked with fleets to develop a refueling infrastructure that works best for fleet applications, whether onsite refueling dispensers for centralized fleets or an expanding network of off-site public refueling stations across the United States.

For fleets looking into onsite fueling, what are their options?

"Onsite fueling with propane autogas is a convenient, cost-effective choice for fleets, especially those that return daily to a home base," said Tucker Perkins, president of CleanFUEL USA, a developer of autogas engine conversion systems and refueling infrastructure. "Infrastructure options range from a basic dispenser and tank set up to a complete retail set up."

According to Perkins, dispensers can be equipped with fleet management software, credit card capability, single or dual hose and stainless or vinyl wrapped finishes. Skid units include horizontal or vertical tanks of different sizes depending on fuel load requirement, above or underground tanks, and pump and motor options designed to accommodate fueling needs.

Perkins advised that fleet managers should consider the number and type of vehicles that will be utilizing the system and, subsequently, the gallons of propane autogas used on a daily basis. Type of payment, accessibility to the site, and the need for fleet management software that collects other information (vehicle ID, driver ID, current mileage, miles per gallon, gallons per driver, date, and time) should also be assessed. It is also important to consider the facility layout and requirements of local jurisdiction pertaining to the installation of fueling systems.

What are the estimated costs involved with onsite fueling systems?

Perkins said costs range from $10,000 for a basic dispenser to $50,000 or more for a complete retail style dispenser and tank set up.

Fuel Quality

Are there potential issues fleet managers should be aware of to ensure proper quality propane fuel?

"Fortunately, for those in the United States, the propane autogas that is purchased usually complies with a standard from American Society of Testing and Materials (ASTM) called HD-5, although those in California may be supplied with propane specified as HD-10," Perkins said. "Propane that meets either of these standards is of excellent quality for use as autogas. Fleet managers should specify the use of HD-5 or HD-10 propane autogas from their supplier to avoid any fuel-quality issues."

Vehicle Availability

According to PERC, the biggest challenge to widespread propane usage in fleets has been a limited number of propane-autogas-fueled vehicles to choose from. However, the organization noted that in recent years, the propane industry has invested several million dollars in the development of new fleet vehicles that run on autogas. Here are PERC's highlights of the latest developments in available propane-powered vehicles - and what's in the pipeline:

  • 2012 Chevrolet Express and GMC Savana 4500-series cutaway vans with dedicated propane autogas systems, which are built, sold, serviced and warrantied by General Motors.
  • ROUSH CleanTech, developer of the propane conversion system for the Ford F-450 and F-550 chassis cabs is developing propane autogas versions of heavier trucks, such as the F-650, with funding from PERC.
  • 2012 F-250 and F-350 pickups and E-Series vans and cutaways, equipped to run on propane autogas, are available for purchase through certain Ford Dealers.
  • A project funded in part by PERC and led by Freightliner Custom Chassis is expected to bring to market, as early as 2012, a heavy-duty propane autogas chassis suitable for a range of applications (including the Type C bus from Thomas Built, recreational vehicles and fire engines, among others).

Advice to Fleet Managers

What should fleet managers consider before making a switch to propane autogas?

Perkins offered these tips: "Fleet managers should research certified autogas vehicle availability; there is a large number of OEM-, EPA-, and CARB-certified dedicated vehicle options, as well as EPA-certified bi-fuel conversion options. They should also consider their ability to refuel and the cost of refueling. Propane autogas refueling can be easily added to already existing infrastructure and can be a nearly seamless transition for drivers. The cost of autogas is consistently cheaper than gasoline and diesel and fuel contracts initiated with suppliers can further decrease that cost."

The Bottom Line

Propane autogas offers business fleets a clean-burning, domestically produced alternative-fuel option with a comparatively low cost of ownership for the right vehicle applications. 

"Autogas is a right-here, right-now option and deserves the attention of fleet managers throughout the country," said Perkins.

If the adoption of propane-powered vehicles by the City of Fort Worth, Austin Gutter King, and other public and private fleets are any indications, fleet managers are taking notice.

About the author
Sean Lyden

Sean Lyden


Sean Lyden was a contributing author for Bobit publications for many years.

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