Why Natural Gas-Powered Vehicles?

They offer a variety of environmental and cost-saving benefits


Clean Energy Fuels Corp., the largest provider of natural gas fuel for transportation in North America and a global leader in the expanding natural gas vehicle market, is continuing development of its America’s Natural Gas Highway. This is a network of LNG and CNG fueling stations at strategic locations along major trucking corridors to form the backbone of a national transportation fueling infrastructure.

The first phase includes 150 fueling stations with approximately 70 anticipated to be open in 33 states by year’s end and the balance in 2013. Many will be co-located at Pilot-Flying J Travel Centers.

“It’s amazing the amount of infrastructure activity that’s happened in the past five years,” Douglas observes. “It may not be too long before we’ll see enough natural gas stations along key interstate corridors for trucks to be able to travel from Los Angeles to New York and back.”

OPERATING RANGE

Along with checking the natural gas fuel availability on truck routes, it is important to take into account operating range, says Douglas. “In general, if your operating range is over 400 miles, it’s usually best to go with LNG. Under 400 miles, CNG can be an option.

“CNG can be used up to 66,000 pounds gross vehicle weight (GVW), with some severe duty applications going up to 80,000 pounds GVW.”

In addition to available fuel type, be sure to check each station’s ease of truck accessibility and its capability to fill commercial truck volumes, he adds. Most CNG stations compress the gas into onsite storage cylinders which can then dispense the natural gas fuel into truck fuel tanks as quickly as diesel fuel.

“Drivers can refuel CNG-powered trucks without needing to go through special training,” he notes. “LNG is a cyrogenic fuel and so those vehicles must be refueled by properly trained individuals.”

ONBOARD FUEL TANKS

As far as fuel tank selection, there is sometimes a tendency to overspec when choosing natural gas tanks since operators are in the habit of carrying a two-to-three day supply of fuel on their diesel trucks, says Douglas.

“In many cases, it’s often impractical to carry much more than a day’s supply of natural gas. Natural gas fuel tanks also can be expensive, so consider carrying only enough fuel for a full-day’s work, plus a 10 percent reserve.”

He advises specifying Type 4 CNG cylinders, which are the lightest weight, but also the most expensive option. Type 4 tanks have a plastic core and are fully wrapped with a composite, such as carbon fiber.

Other less expensive options are Type 2 and Type 3 CNG tanks. These have a steel or aluminum core and are composite wrapped.

Kenworth, like other truck OEMs, offers a number of tank options for order on its natural gas trucks. Fuel tank placement depends on the type of truck, chassis configuration, equipment specification choices and how much fuel is needed to be carried.

“It’s important to carefully consider the possible impact of tank placement choices on wheelbase length, weight distribution and turning radius,” Douglas says.

The fuel savings, coupled with the longer trade cycles of some vocational trucks, can make a positive return on investment (ROI) on NGVs attainable now, even without government incentives, he says, and notes that the Clean Cities Alternative Fuel Price Report can be a help in determining whether the savings from alternative fuels can provide a high enough ROI. Updated every three months, it offers a comparison of CNG, gasoline, diesel and biodiesel fuels on a straight price comparison basis and an energy-equivalent basis.

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