Propane Benefits and Considerations
Also known as liquefied petroleum gas (LPG), propane is a domestically produced, well-established fuel. Using propane as a vehicle fuel increases energy security, provides convenience and performance benefits, and improves public health and the environment.
In 2015, the United States imported almost half of the approximately 19.4 million barrels of petroleum per day it consumed and transportation accounted for nearly three-fourths of total U.S. petroleum consumption. With much of the worldwide petroleum reserves located in politically volatile countries, the United States can be vulnerable to supply disruptions.
The vast majority of propane consumed in the United States is produced here and distributed via an established infrastructure. Therefore, fueling vehicles with propane is one way to diversify U.S. transportation fuels and increase the nation's energy security in the process.
Vehicle and Infrastructure Availability
A variety of light-, medium-, and heavy-duty propane vehicle models are available through original equipment manufacturers (OEMs) and select dealerships. For options, see the Alternative Fuel and Advanced Vehicle Search, the Model Year 2018: Alternative Fuel and Advanced Technology Vehicles spreadsheet, or the Clean Cities Vehicle Buyer's Guide or the Clean Cities Guide to Alternative Fuel and Advanced Medium- and Heavy-Duty Vehicles.
While propane vehicles can cost several thousand dollars more than comparable gasoline vehicles, the cost of propane is typically lower than gasoline, so the return on investment can be quick. In the case of school buses, propane models can cost on par with comparable diesel vehicles depending on manufacturer bids. Fleets and consumers also have the option of economically, safely, and reliably converting in-use light-, medium-, and heavy-duty gasoline vehicles for propane operation using qualified system retrofitters. It's critical that all vehicle and engine conversions meet the emissions and safety regulations and standards instituted by the U.S. Environmental Protection Agency, the National Highway Traffic Safety Administration, and state agencies like the California Air Resources Board. Learn about propane vehicle conversions.
By using the AFDC Station Locator tool, fleets and private users can identify public and private stations near them. Propane stations are categorized as either primary or secondary, and the methodologies section explains the categories, based upon their experience fueling vehicles. Fleets can use existing public infrastructure or work with local propane marketers to establish private infrastructure. It is important that fleets understand the important elements of negotiating a supply contract. Costs will depend on the volume of fuel that’s indicated in the contract and the complexity of the equipment being installed. Learn more about the cost of propane infrastructure.
Fuel Economy and Performance
Propane at primary infrastructure sites typically costs less per gallon than gasoline and offers a comparable driving range to conventional fuel. Propane has a higher octane rating than gasoline (104 to 112, compared with 87 to 92 for gasoline) and potentially more horsepower, but its lower British thermal unit (Btu) rating per gallon results in lower fuel economy. However, the price per gallon can quickly offset the lower fuel economy.
The potential for lower maintenance costs are one reason behind propane's popularity for high-mileage vehicles. Propane's high octane rating, combined with its low-carbon and low oil-contamination characteristics, has resulted in improved engine life compared to conventional gasoline engines. Because the fuel's mixture (propane and air) is completely gaseous when entering the engine's combustion chamber—and does not require an enriched fuel mixture for combustion such as with many liquid fuels—cold start problems can often be reduced.
Public Health and Environment
Compared with vehicles fueled by conventional diesel and gasoline, propane vehicles can produce lower amounts of some harmful air pollutants and greenhouse gases, depending on vehicle type, drive cycle, and engine calibration. Learn more about propane emissions.