As Triangle motorists adjust to paying record prices of more than $3.18 a gallon for gasoline, Ronald Orr thinks we might like to hear about a different kind of gas that costs less than $2.

Orr, a retired engineer, has a fleet of six cars and trucks that run on CNG -- compressed natural gas.

There are only a few places you can buy the fuel around the Triangle, and there aren't any dealers in North Carolina that sell the only new CNG car on the market -- the Honda Civic GX.

So why is Orr an evangelist for CNG?

Unlike gasoline, natural gas is abundant in the United States, relatively cheap and squeaky clean.

"It's the only alternative fuel that's demonstrably cheaper than gasoline, unlike ethanol and biodiesel," said Orr, 68. "With them, you pay more to be green. And CNG essentially doesn't pollute."

A new listing by the American Council for an Energy Efficient Economy ranks the CNG-fueled Civic as the nation's most environmentally friendly "green" car, above the vaunted Toyota Prius. Prius and other hybrids get better fuel economy -- but they still burn gasoline, which can't touch natural gas for its low levels of carbon, nitrogen, sulfur and other emissions.

"That car is considered the cleanest internal combustion engine in the world," said Tobin Freid, who heads the nonprofit Triangle Clean Cities Coalition. "Driving that car is the equivalent of carpooling with 64 other people."

Orr keeps a couple of CNG-fueled Dodge vans in Chapel Hill, where he is coming this week to visit his daughter and new grandson. (He spends most of his time in California, and that's where the rest of his CNG vehicles are -- including a Civic and a Ford Crown Vic.)

Most of the nation's CNG vehicles are in state and local government fleets. Raleigh has 15 Civics and eight other cars, trucks and vans that burn compressed natural gas.

Where to fill up

When Orr is in the Triangle, he fills up at Raleigh's CNG fuel stop on New Bern Avenue, with PSNC Energy on Cabarrus Street, or at other government fleet stations in Chapel Hill and Hillsborough. Since CNG is not a liquid, it is measured in the energy equivalent of a gallon of gas.

The city of Raleigh's posted price Monday for a CNG gallon was $1.63.

Honda markets the Civic GX only in California and New York, the only two states with more than a scattered number of fueling stations. Orr says a family friend in California bought a Civic GX because it qualified him for the freeway express lanes otherwise reserved for carpoolers -- and because he could buy the fuel for about $1.50 a gallon.

Some CNG drivers who heat their homes with natural gas invest about $4,000 extra to install a home device that compresses the gas and refills the car overnight.

Orr keeps tabs on the locations of fuel stations around the country, so he knows where he can drive and where he can't. Because CNG is a gas, it takes up more space than liquid fuel. The tanks are bigger and stronger -- like scuba air tanks, Orr said -- and the size limits how far the vehicle will go between fuel stops.

150 miles per tank

Raleigh's CNG Civics are driven mostly by city inspectors who get about 27 miles per gallon -- about 150 miles per tankful -- in the city. The fuel tank takes up much of the trunk of the Civic, and part of the cargo bed of a pickup truck.

"It's easy for them to run through a tank a day, and they have to manage their routes accordingly to make sure they make it back to the station to refuel," said Travis Brown, the city of Raleigh's fleet superintendent.

But he says the CNG cars perform well, and they could be worth the investment for drivers who, like Orr, are serious about energy issues.

"If you want a vehicle that's going to help the environment, that would help us have less dependency on foreign oil, that might be the way to go," Brown said. "Especially if you're just going to use it for commuting here within the city, it would be great."