According to the California Energy Commission Autogas has been used as a transportation fuel since 1912. Today, there are about over half a million LPG-powered vehicles running in the U.S., “and growing,” says Mike Taylor, business development manager at the Propane Education and Research Council. These vehicles have access to almost 3,000 public filling stations in the U.S. Elsewhere in the world, propane powers nearly 25 million cars and trucks. Over 70,000 fuel stations offer Autogas worldwide.

An Autogas station for fleets costs only $10,000 to $15,000, and consists of a simple steel storage tank, a pump and dispenser. It can be set up quickly on a fleet’s premises, Taylor says, and “a supplier will work with any long-term customer. He’ll put in the station for free, in return for a modest upcharge on the per-gallon price. Mobile refueling is available if you’re trying to make up your mind about switching over your fleet. Fill rates are equivalent to gasoline and diesel,” or 5 to 7 gallons per minute. Autogas prices vary around the country and according to agreements with suppliers. A typical per-gallon price is $2 to $2.50, though a consumer might pay $3 at a U-Haul outlet. Because propane is a popular heating fuel in rural areas, prices temporarily spiked during extremely cold weather last winter. But Taylor says a lot of that was due to supply interruptions, and users with contracts were not affected.

Current propane engines are based on gasoline blocks, as are scores of available conversion kits. A complete professional light-truck conversion can cost anywhere between $9,000 to $12,000. Converting a midrange truck with gasoline engines may cost a little more. Cummins Westport dropped its Autogas 5.9-liter ISB in 2009 for lack of sales, but Taylor says that can change. “Our growth is Class 1 through Class 7,” he says. “We haven’t pursued the over-the-road market. But we are experimenting with dual-fuel, and with dedicated diesel-block-type engines.

Now there is the (gasoline-block) 8.8-liter Power Systems International engine that gives you benefits of diesel. There’s also the 8-liter Powertrain Integration Pithon engine that Freightliner Custom Chassis is using in the S2G.” Taylor says PERC is funding two R&D projects, though he declined to name the companies involved.

“We are developing engines that will fit in the heavy-duty market, for delivery and regional carriers.”

Fleets such as Frito-Lay and United Parcel Service run hundreds of Autogas-fueled trucks, and in March UPS announced that it was acquiring 1,000 more LPG “package cars”. Fuel-system suppliers such as Roush CleanTech offer testimonials from commercial and municipal customers who appreciate the fuel’s low price, clean-burning characteristics and gasoline-like performance.