As chance would have it, I was planning to drive to a baseball game in Milwaukee last month when General Motors called to send over a Chevrolet pickup that runs on gasoline and compressed natural gas (CNG). The road trip became a good opportunity to test a bifuel truck over long distances.
Equipped with a 6.0-liter V-8 engine, six-speed automatic transmission, 4:10 rear axle and four-wheel drive, the 2015 Chevrolet Silverado 2500 crew cab behaved much like a standard three-quarter-ton pickup. Rated to tow up to 13,000 lb, this truck also included a $9,500 CNG option that, according to GM, gives the truck a combined range of 650 miles.
The CNG package didn't come from the factory, but it was coordinated with the factory. After installing a special engine, GM shipped the truck to an authorized upfitter. There, a fuel tank was installed in the bed, along with extra plumbing. This work preserved the vehicle's original power-train warranty.
I topped off the truck's 36-gallon gasoline tank and its CNG tank, which holds the equivalent of 17 gallons, and headed out from Indianapolis on Interstate 65. Locating filling stations turned out to be easier than expected with a mobile app called CNG Fuel Finder. My first stop was in Gary, Ind., where I found a pump at a ready-mix-concrete plant that Mokena, Ill.-based Ozinga Bros. operates. The detour took me a few miles off the beaten path, but with prices equal to $2.56 per gallon of gasoline, I happily filled up for less than $24.
The truck would have made it the rest of the way to Miller Park without another fill-up, but range anxiety set in, prompting me to pull over to a truck stop in Sturtevant, Wis. The pump was not clearly labeled, so I had to flag down an attendant, who directed me to the big-rig lanes. As I waited for the natural gas to finish dispensing, the Chevy, sandwiched between two 18-wheelers, looked comically small. Even stranger was the receipt, which said I paid, at just $1.99 per gallon, a grand total of $15.59 for the fill-up. Victory was in the air: The Milwaukee Brewers beat the Toronto Blue Jays 6-1.
Driving more than 560 round-trip miles on natural gas, the Chevy ran the bases well, but it didn't execute flawlessly. Finding fueling stations wasn't a problem, but more fill-ups were required. Also, the engine always started up on gasoline and then switched to CNG—I could feel a shudder when the transition took place. This meant I could not let the gasoline tank run empty, or I'd be stuck.
GM's integration of the truck's fuel readouts was a bit confusing. A large button on the center console allowed me to switch between fuels, which was convenient; but, rather than adding a separate CNG fuel gauge, GM had the dashboard needle automatically switch over without warning. I had to scroll through the instrument cluster's digital display to check the level of the fuel I was not using. Still, the truck gave an accurate estimate of remaining mileage on either fuel—at most, about 200 miles on CNG—and power was adequate. The engine on CNG produces 301 horsepower and 333 lb-ft of torque, GM says. On gasoline, it is rated at 360 hp and 380 lb-ft.
Key Stats
Finding a place to refuel a CNG vehicle is less of an issue today than it was in the past, so variations in local gas prices and annual mileage are bigger concerns to a fleet owner looking to recoup an investment. GM offers only the bifuel option on its heavy-duty trucks—a standard model like this starts out at $42,655. The CNG package, trailering equipment, navigation system and other options on this tester pushed the sticker price to $58,800, including delivery charges.
GM is not required to provide fuel- economy estimates for this truck size, but I calculated an impressive 16 mpg on CNG alone. When about a gallon of gasoline burned for startups was factored in, that figure dropped by a trivial amount. With U.S. gasoline and CNG prices at $3.46 and $2.11 per gallon, respectively, it would take three to four years driving 30,000 miles annually to reach a payback. Using CNG 75% of the time, GM estimates saving $2,000 per year.
