Summer is here, and that means grilling – and propane. But Curtis Donaldson, president of CleanFuel USA, hopes the gas will soon be able to fuel more than just barbecues.

Propane is cleaner burning than gasoline, and – while Donaldson admits it isn’t the perfect alternative – it has a few big advantages over cellulosic ethanol or algae-based biodiesel for vehicles, he says.

It’s available now. It won’t take Nobel Prize-quality breakthroughs in research and development to bring it to market and it’s not outrageously expensive.

Propane prices, like gasoline and diesel, have grown. But while they are higher than they’ve ever been, propane prices haven’t risen as much. It costs about $2.30 per gallon, not including a 50 cent-per-gallon federal credit, Donaldson said.

It also is domestically produced.

These factors, among others, are driving the rekindled interest behind propane, a relatively clean fuel that’s largely a byproduct of natural gas or crude oil processing, to fuel trucks and fleet cars. Roush Performance sells a Ford F150 pickup truck modified to run on propane, for example, and several municipalities are studying ways to put more propane cars into their fleets.

In a few weeks, CleanFuel hopes to unveil a deal with an oil company to install propane dispensers (i.e., pumps) at its stations.

CleanFuel doesn’t refine fuel. Instead, it produces dispensers. It is also working with General Motors on a 6-liter engine for shuttle buses that will run on propane. GM already sells an 8.1-liter propane engine for larger trucks.

Although Americans mostly know the fuel as the stuff that lights up their gas barbeques, liquefied propane has been part of the transportation-fuel market for decades. There are roughly 10 million propane vehicles worldwide and 200,000 in the United States.

Interest grew rapidly in the 1970s, but dwindled with declining oil prices. Like methane (otherwise known as natural gas), propane occurs naturally as a gas, but can be compressed into a liquid fuel.

The company, along with many propane retailers, largely targets owners of delivery cars and fleets. Propane requires a special dispenser, and delivery vehicles fill up at central stations often owned by the owner of the cars.

Making a play to the larger consumer market would require a large overhaul of the nation’s energy infrastructure. It’s a challenge ethanol companies know well. Ethanol refiners have tried to expand the footprint for blends of 85 percent ethanol and 15 percent gasoline for years, but to date, only about 1,400 stations have ethanol pumps.

That difficulty could be part of the reason why the propane market is dwarfed by the size of the market for petroleum-based fuels today. The United States consumes more than 145 billion gallons of liquid fuel per year, or 400 million gallons per day, according to the Energy Information Administration and other estimates.

And growing the market more quickly than supply could drive up prices for propane, reducing its advantage.

“We can be a fuel for everybody, but we can probably put 1.5 billion gallons [per year] into the market right now without a disruption of supply and demand,” Donaldson said.

Still, the fleet market is sizeable enough for smaller companies or divisions of large ones. Fleet owners own roughly 15 million buses, trucks and cars. The market has also drawn the attention of electric-car companies like Miles Automotive and Zenn Car, as well as Oorja Protronics, which makes a methanol fuel cell for forklifts.

Propane engines get about five percent lower gas mileage than regular engines. The emissions reductions, meanwhile, can be substantial. According to a study conducted by Argonne National Laboratories, total hydrocarbons emissions in light-duty vehicles built specifically to run on propane could be reduced by 40 percent, while heavy-duty vehicles could reduce emissions 80 percent.

“Unlike natural gas, propane is not a greenhouse gas (GHG) when released directly into the atmosphere,” Argonne scientists wrote in the summary of their report.

After studying the entire life cycle of propane used in converted light-duty vehicles, the laboratories concluded that propane reduced greenhouse-gas emissions by 21 percent to 24 percent, all together, and petroleum use by 98 percent to 99 percent.

Propane dispensers also cost less than other alternative fuel dispensers, such as compressed natural gas – another popular fleet-car fuel – or ethanol. Putting propane into a station might cost $35,00 before federal tax credits, Donaldson said, while a dispenser for compressed natural gas can cost $600,000. 

Another advantage: If you’re going to a barbeque, you can always siphon fuel off the engine in a pinch.