Propane autogas fuels this work truck and walk behind mower. More than 270,000 vehicles across the United States depend on public propane refueling stations or private stations located at a fleets home base.

Propane autogas fuels this work truck and walk behind mower. More than 270,000 vehicles across the United States depend on public propane refueling stations or private stations located at a fleet’s home base.

Credit: Propane Education & Research Council

Propane autogas is the world’s leading alternative fuel and the third most popular fuel in the U.S. At one-half the cost of diesel and gasoline, it’s a clean-burning fuel that doesn’t dirty engines as much as gasoline and diesel.

Government agencies are increasingly specifying propane autogas, also known as liquefied petroleum gas (LPG), for buses, lawn mowers, pickup trucks, police cars, shuttles, and street sweepers.

A growing portfolio of products from manufacturers and aftermarket upfitters provide equivalent horsepower, torque, and towing capacity as conventional fuels at a much lower cost of ownership. Although known as propane, when used to fuel vehicles it’s called propane autogas because it’s calibrated for on-road use.

Vehicles that run on propane autogas emit 12% less carbon dioxide, 20% less nitrogen oxide, and up to 60% less carbon monoxide than gasoline vehicles.

They work like gasoline-powered vehicles with spark-ignited engines. Propane is stored as a liquid in a relatively low-pressure tank (about 150 psi) and travels along a fuel line into the engine compartment. The supply of propane to the engine is controlled by a regulator or vaporizer, which converts the liquid propane to a vapor. The vapor is fed to a mixer located near the intake manifold, where it is metered and mixed with filtered air before being drawn into the combustion chamber where it’s burned to produce power, just like gasoline.

Application, refueling affect vehicle type

Propane autogas vehicles can either be conversions from gasoline vehicles or purchased new. Therefore, the first step in specifying a vehicle is deciding on a dedicated or bi-fuel vehicle and then converting a small test fleet to determine the right setup.

  • Dedicated: Manufactured to run solely on propane autogas.

Generally about 10% more than diesel counterparts.

Good for fleets with a defined route and centralized refueling.

  • Bi-fuel: A gasoline (not diesel) vehicle that’s been converted to run on either propane autogas or gasoline. EPA-certified conversion kits sold by aftermarket suppliers can be installed on existing vehicles. For a list of bi-fuel conversion vehicle options and to find out if your existing vehicles can be retrofitted, visit Using bi-fuel is less expensive than buying a new vehicle and good for long-range applications because drivers can switch to gasoline if a refueling station is out-of-reach.

Product offerings used to limit a fleet manager’a ability to take advantage of alternative fuels, but the number of light- and medium-duty propane autogas vehicles has surged in recent years. Engines and fueling systems are also available for heavy-duty vehicles like street sweepers and transit buses.

Refueling is comparable to filling up with gasoline or diesel. The main difference is that a propane autogas nozzle is threaded into the fuel tank to eliminate spillage and prevent fuel theft.

Accessibility also has been a concern of fleet managers. But with about 2,500 refueling stations, such as gas stations and hardware stores, propane is readily accessible and is the only alternative fuel with fueling stations in all 50 states. To find locations in your state, visit the U.S. Department of Energy’s Alternative Fuels Data Center.

Although you’ll have to add propane autogas equipment to your existing fuel stations, federal incentives cover up to 30% of the installation cost. Some propane retailers will pick up the cost when a fleet agrees to a fuel contract. Costs will depend on the contract and equipment complexity.

Fifteen propane autogas refueling stations can be installed for the cost of one compressed natural gas station.