Propane Basics

Propane powers nearly 60,000 vehicles in the United States.1 Fleets around the United States have Propane is a popular choice for many fleet vehicle applications, including school, shuttle, paratransit, and transit buses as well as delivery trucks, vans, taxis, law successfully implemented propane enforcement vehicles, and vocational trucks. Photo by Propane Education & vehicles in many types of applications, Research Council. including school buses, shuttle buses, step vans, and law enforcement How is propane produced autoignition temperature, so it takes vehicles. Propane is also frequently and distributed? significantly more heat for the fuel used in off-road applications, such Propane is a byproduct of natural gas to ignite without a flame or spark. as forklifts, commercial landscape processing and crude oil refining. As of Propane tanks are also 20 times more mowers and equipment, and other 2020, more than 93% of the U.S. propane puncture-resistant than gasoline tanks. 2 farm equipment. The advantages supply was produced in North America. Propane vehicle tanks are equipped Propane is shipped from its point of with pressure relief devices that release of propane include its domestic production to bulk distribution terminals fuel in a controlled manner in the availability, performance, and via pipeline, railroad, barge, truck, or event of overfilling, heat expansion, emissions benefits. tanker. Propane marketers then purchase or fire. The National Fire Protection propane at terminals and distribute the Association (NFPA), U.S. Department of What is propane? fuel to customers, including retail or Transportation, and other organizations provide safety guidelines for propane Also known as liquefied petroleum private fueling stations. vehicles, as well as propane fueling gas (LPG), propane is an odorless Chemically identical to conventional equipment.3 A list of applicable codes and hydrocarbon (C H ) gas at normal 3 8 propane, renewable propane is produced standards is available on the Alternative pressures and temperatures. It is the same from biomass-based feedstocks, including Fuels Data Center (AFDC) website (afdc. propane used for residential heating, used cooking oil, animal fats, or 20% energy.gov/pdfs/48612.pdf), and the cooking, and grills. Propane that is dimethyl ether. Renewable propane is Propane Education & Research Council marketed and sold exclusively for use in currently produced in limited quantities at (PERC) provides training on vehicle motor vehicles is sometimes branded as biodiesel refineries. maintenance4 and fuel dispensing.5 Autogas, to reflect that it is measured, taxed, and dispensed as a vehicle fuel. Is propane safe for Fleets implementing propane vehicles But it is virtually identical to conventional should consider maintenance facility propane. When pressurized in a tank to vehicle use? modifications. These may be required 150 pounds per square inch, it becomes a Just like conventional vehicles, based on several factors, including the liquid with an energy density 270 times propane vehicles must comply with degree of repair work done in the facility greater than that of its gaseous form. all applicable regulations, including and the facility’s physical configuration Federal Motor Vehicle Safety Standards and layout. Fleet managers should also be (FMVSS). Compared to gasoline and aware of the applicable codes and engage diesel, however, propane has a higher their local Authority Having Jurisdiction

1 Propane Education and Research Council. 2021. (propane.com) 2 EIA U.S. Propane Production by Source, 2008-2019 (eia.gov/energyexplained/hydrocarbon-gas-liquids/where-do-hydrocarbon-gas-liquids-come-from-in-depth.php) and EIA U.S. Imports of Propane (eia.gov/dnav/pet/hist/LeafHandler.ashx?n=PET&s=MPAIM_NUS-Z00_2&f=A) 3 National Fire Protection Association, NFPA 58, (nfpa.org/codes-and-standards) 4 Propane Autogas Technician Training (propane.com/safety/safety-articles/propane-autogas-technician-training) 5 Dispensing Propane Autogas Training Program (propane.com/safety/safety-articles/dispensing-propane-autogas-training-program) (AHJ) regarding such modifications. The AHJ will also have information about any local requirements regarding the use or storage of gaseous fuels in underground parking garages or maintenance facilities. The PERC website includes informational videos that cover these topics.6

How do propane vehicles work? Propane vehicles have been widely used and refined for decades.

• Operation. Propane vehicles operate much like gasoline vehicles with spark-ignited engines. There are two types of propane fuel-injection systems This illustration of a bi-fuel vehicle highlights both the propane and gasoline fuel available: vapor and liquid injection. system components. Photo from AFDC. In both types, propane is stored as a liquid in a relatively low-pressure tank. The liquid injection technology What propane vehicles (CARB) regulations for applicable states, allows more precise control of the fuel are available? and FMVSS for the appropriate vehicle delivery, resulting in improved engine weight classification). For a list of EPA Light-, medium-, and heavy-duty performance and efficiency. compliant propane conversion systems propane vehicles are available for various and engines, see the EPA website at epa. • Performance. A propane vehicle’s applications in either dedicated or bi-fuel gov/vehicle-and-engine-certification/ power, acceleration, and cruising speed configuration. Buyers can purchase lists-epa-compliant-alternative-fuel- are similar to those of a conventionally vehicles through OEM dealerships conversion-systems. fueled vehicle. Bi-fuel vehicles or have existing in-service vehicles have two separate fueling systems, converted to propane. Note that the list is not necessarily enabling the vehicle to run on either comprehensive. EPA adds conversion Certain OEMs also offer propane “prep propane or gasoline. This provides the systems upon request of the system’s packages,” which allow a qualified flexibility of using either fuel, which manufacturer and advises checking the system retrofitter or vehicle modifier typically provides bi-fuel vehicles a list periodically for updates. Customers (QSR or QVM) to install a propane fuel greater range than dedicated propane should ask to verify a manufacturer’s delivery system before the vehicle is or gasoline vehicles. Extra storage EPA or CARB certificate. delivered to the customer. tanks can increase range, but the System manufacturers may perform the tank size and additional weight affect To find available propane vehicles and conversion themselves or work closely payload capacity. Because a gallon of engines, see the AFDC’s Vehicle Search with a QSR/QVM, also referred to as an propane has 27% less energy than a at afdc.energy.gov/afdc/vehicles/search. “upfitter” or “installer.” A well-qualified gallon of gasoline, the fuel economy QSR/QVM will have established of propane vehicles is slightly lower. How can I find reliable procedures, best practices, and technical However, propane has a higher training for the installation process. It pump octane number than gasoline and approved propane is important to understand these and (104–112 compared to 87–92 for conversions? review documentation on conversion gasoline7) and some original equipment Conversion systems must be compliant practices, procedures, and training when manufacturers (OEMs) offer dedicated with all safety and emissions regulations considering any conversion equipment engines optimized to take advantage for the states or regions where the vehicle and services. For more information, of this higher rating. This can result is intended to operate (e.g., emissions consult the AFDC Propane Vehicle in improved performance and fuel certified as compliant in accordance with Conversions page (afdc.energy.gov/ economy over non-optimized engines. U.S. Environmental Protection Agency vehicles/propane_conversions.html) (EPA) or California Air Resources Board or What Fleets Need to Know About

6 Fleet Garaging Requirements (propane.com/safety/safety-articles/fleet-garaging-requirements) 7 AFDC Fuel Properties Comparison (afdc.energy.gov/fuels/fuel_properties.php)

2 Alternative Fuel Vehicle Conversions, Life-Cycle Environmental and Economic Retrofits, and Repowers (afdc.energy. Transportation (AFLEET) tool (greet. gov/files/u/publication/afv_conversions_ es.anl.gov/afleet) helps estimate retrofits_repowers.pdf). petroleum use, emissions, and cost of ownership of light- and heavy-duty Clean Cities coordinators can help vehicles for a variety of fuels. prepare vehicle specification and locate reliable providers to ensure a quality Lower maintenance costs are also often installation. Clean Cities also provides reported, particularly for high-mileage technical assistance to help fleets ensure vehicles. Also, propane’s low-carbon and quality control for converted vehicles. low oil-contamination characteristics may result in longer engine life.8 How much do propane vehicles cost? Is it easy to fuel a While the initial purchase price of propane vehicle? propane vehicles may be several Fueling a propane vehicle is similar to Fueling a propane vehicle is similar thousand more than that of comparable fueling a conventional vehicle and takes to fueling a conventional vehicle conventional vehicles, propane vehicles about the same amount of time. There and takes about the same amount can provide an acceptable return on are minimal concerns around spillage of time. Some attendant training is investment. A light-duty conversion may and ground contamination because the required, however. Photo by Werner Slocum, NREL 57379. cost several thousand dollars, while a new fuel is dispensed through a sealed fueling propane vehicle may have incremental connector and hose assembly. As with costs greater than $10,000. However, all vehicles, however, individuals should new vehicles to be equipped with the propane school buses are close to cost recognize proper safety precautions— quick-release “Type K15” connector parody with comparable conventional such as not smoking—when fueling. beginning on January 1, 2020.3 For diesel buses. Fleet managers should also vehicles with the ACME connector, there consider costs for fueling infrastructure The “Type K15” quick-release nozzle is an adapter for the Type K15 nozzle. if they do not currently have access to improved the fueling experience by Because some training is required, propane fueling sites (see station map allowing one-handed fueling and not propane may only be dispensed at public image), as well as the potential cost of requiring the use of personal protective stations by a qualified attendant (similar any upgrades that may be required to equipment such as gloves and face shield, to a full-service gasoline or diesel pump). their maintenance facilities. which are required for the older ACME connector. The K15 also substantially Likewise, drivers or attendants will need Today, many states offer incentives limits fugitive emissions compared to some training to operate private pumps. and tax credits that reduce the cost of other connectors. NFPA 58 requires all propane vehicles and infrastructure, and shorten the payback period. For the latest information on these types of incentives and tax credits, visit the AFDC’s Federal and State Laws and Incentives section at afdc.energy.gov/laws. Also contact your Clean Cities coordinator to learn about other local incentives and tax credits that may be available.

Thanks to typically lower fuel costs, particularly for fleets that negotiate fuel contracts, the upfront cost of vehicles and infrastructure can be recovered relatively quickly because of the lower cost per mile to operate Thousands of fueling stations across the country provide propane. To map propane vehicles. For help determining return stations near a specific address or city, use the Alternative Fueling Station Locator on investment, the Alternative Fuel (afdc.energy.gov/locator/stations). Source: AFDC Alternative Fueling Station Locator Data.

8 AFDC, Propane Vehicles (afdc.energy.gov/vehicles/propane.html)

3 How much does propane How do propane vehicle fuel cost and where is emissions compare with it available? those of gasoline vehicles? Propane can be priced lower than Tailpipe emissions from propane gasoline or diesel fuel. However, fleet vehicles are often comparable or even managers should carefully consider their lower than those of conventionally options when establishing private fueling fueled vehicles with modern emissions or using public sites. To find stations in controls, depending on vehicle type, your area, visit the Alternative Fueling This Colorado school district started drive cycle, and engine calibration. Station Locator or download the mobile with one 1,000-gallon storage tank Based on calculations from Argonne app from the AFDC website at afdc. and later expanded its capacity by National Laboratory’s AFLEET tool, energy.gov/stations. The Station Locator adding a second tank. Photo by Dennis for example, school buses running on includes both public and private stations. Schroeder, NREL 31321. propane can reduce nitrogen oxides (NOx) emissions by nearly half compared • Public fueling stations. There are For current information on retail to diesel vehicles. Vehicles with near- more than 2,600 public propane fuel prices, refer to the Clean Cities zero NOx engines can enable even larger stations in the United States. The Alternative Fuel Price Report (afdc. reductions. When considering a wells- Station Locator tool allows users to energy.gov/fuels/prices.html). This report to-wheels emissions analysis, propane search for public and private propane provides regional average retail prices for use reduces GHG emissions by nearly fueling stations and defaults to showing both public and private stations, so it can 13% compared to gasoline vehicles. only public “primary” stations. Primary potentially serve as a barometer on retail For renewable propane, life cycle GHG stations must be staffed during regular fuel pricing in your area. emissions are approximately half of business hours, must not require drivers conventional propane, according to to call ahead to fuel, must accept credit estimates from the Propane Education & cards as a payment type, and must be How much does it cost Research Council (PERC). able to fuel vehicles at a rate of 8–12 to install a propane gallons per minute or faster, or at a rate fueling station? similar to filling a gasoline vehicle. Where can I learn more Users may expand their search to Propane fueling infrastructure is very about propane? similar to that of gasoline and diesel. include all propane stations by using To learn more about propane as a The fuel is stored onsite, typically in the “include stations with limited transportation fuel, visit the AFDC’s aboveground tanks ranging from 1,000 to fueling” checkbox. To obtain the best Propane Fuels and Vehicles section 30,000 gallons.9 fuel price at public fueling stations, (afdc.energy.gov/fuels/propane. fleet managers should negotiate The cost of establishing propane html), contact your local Clean Cities competitive pricing. Using stations infrastructure can be as low as $40,000, coordinator (cleancities.energy.gov/ without such an agreement may result depending on the size and number of coalitions.html), or visit the PERC in paying higher prices. storage tanks and dispensers, whether website (propane.com). For case studies infrastructure is already in place (e.g., and successful stories about propane • Private fueling stations. The price vehicles, see the AFDC Case Studies of propane is typically based on the electricity lines), and payment system 9 page (afdc.energy.gov/case). volume that a fleet uses. Local propane requirements. marketers are present in most every However, local propane marketers often community across the United States. provide new fueling infrastructure at In addition to providing fuel, they little or no cost for customers under can provide expertise in establishing a fuel supply contract. Note that all private fueling infrastructure. A local infrastructure must comply with Clean Cities coordinator can also local codes and standards, and it’s provide assistance for establishing important to involve the local AHJ infrastructure. It’s important to consult early in the process. Infrastructure costs with a number of local fuel providers are documented in the report, Costs and establish a fuel contract that Associated with Propane Vehicle Fueling For more information, visit: secures fuel at a fixed cost, regardless Infrastructure.9 afdc.energy.gov of seasonal commodity price or supply fluctuations. DOE/GO-102021-5555 • June 2021

9 Costs Associated with Propane Vehicle Fueling Infrastructure. 2014. (afdc.energy.gov/files/u/publication/propane_costs.pdf)

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