Says the butcher: “We eat what we sell.” Says Kwik-Trip: “We burn what we sell.” That’s natural gas, sold in liquefied and compressed form at 15 of the 430 retail filling stations the company operates in Wisconsin, Minnesota and Iowa. Currently, 34 of the firm’s own trucks and tractors use LNG and CNG because managers wanted experience with both types.
“We wanted to look at them both, to learn the advantages and disadvantages, to learn how to spec them, so that as we talk to fleet customers we can speak to our experiences,” says Joel Hirschboeck, superintendent of alternative fuels at the company’s headquarters in La Crosse, Wis. Its vehicles have Cummins Westport 8.9- and 11.9-liter gas engines, which can burn either CNG or LNG.
Which is better – LNG or CNG? “It’s what fits your application,” he says. “LNG’s biggest advantage is more energy in a smaller container. Of course, infrastructure is important, and CNG is less costly for that.”
An LNG truck or tractor has a range of approximately 600 miles with a 119-diesel-gallon-equivalent tank. A CNG truck uses two 45-DGE tanks with a 450-mile range. More bottles would give more range for a CNG vehicle, but they also would add weight and cost.
“We don’t need the longer range, so we will go toward CNG and refuel en route on the longer runs,” Hirschboeck says.
The shortest-range tractors in the fleet are a pair of yard “goats,” but they run on LNG “because at the time we ordered, there wasn’t a good CNG solution for fuel storage – the chassis were too small to mount the tanks. But now they do have CNG capability.” The yard tractors are from Capacity and Autocar, and have Cummins ISL G engines.
“We’ve had good success with that engine, and use it in straight trucks, too,” he says. “It works well with diminishing loads. We have a couple of demo units with the ISX12 G, one 350 horsepower and one 400, and we’re seeing good success, too.” The 12Gs are in tractors that gross up to 80,000 pounds.
The company does a lot of driver training, with two to three hours up front plus ongoing training. Drivers need to learn more about the system itself, plus how to manage low-end torque, and the fact that your foot on the floor at higher speeds doesn’t give any more horsepower.
“Natural gas gives pretty close to diesel performance in our application and the way we’ve got our trucks set up, including governing at 60 mph,” he says.
Tractors are a little bit of everything, including Peterbilt 384, Kenworth T440, Freightliner M2-112 and Volvo VNM.
“We wanted to individually understand the product lines and also the corporate support structures,” Hirschboeck says. “We’re working with the different dealerships and OEMs to understand where their service and support are on natural gas vehicles. They’ve been good with all of ‘em, especially at the local dealer level with shop support, and they’ve all got trained technicians.”
Vehicle price premiums range from $30,000 to $60,000 each, depending on the tank package, Hirschboeck says. “We had Agility (the fuel system supplier) come out and install the vehicle tank systems on site, and we now can install the systems on our own. We have 15 natural gas stations, and the cost for each was $750,000 to $1.5 million,” with LNG equipment being more expensive.
Natural gas fuel is half the price of diesel, so the break-even point for vehicles is 200,000 miles.
Kwik-Trip sells about 1,000 gallons of natural gas a day, including to the public, and the fleet’s trucks use the same public facilities.
They pump at 10 to 12 gallons per minute; most have two dispensers with four nozzles, standard and transit (for buses).
“We run 24/7, so LNG boil-off from truck tanks (when they warm) is not a problem. We can hold LNG for seven days. But we can turn any venting from on-site storage tanks into CNG, automatically – they’re set up for that.
“It’s a very safe fuel,” Hirschboeck says. “All trucks have safety measures, with positive nozzle locks so there’s no leakage while fueling, like you can have with gasoline and diesel.”