INDIANAPOLIS, Ind. — Much of the buzz at this year’s Green Truck Summit revolved around the potential of natural gas to lower operating costs for fleets.

Natural gas, in liquefied or compressed form, is quickly gaining credibility in high-mileage applications.

A Class 8 truck could cost $55,000 to upfit to natural gas, but Bill Zobel, senior vice-president, business development with gas supplier Trillium USA, noted a truck consuming 22,000 gallons of fuel a year would deliver a 1.8-year payback when the spread between diesel and natural gas prices is $1.50 per gallon. It’s currently closer to $2 per gallon.

A payback of less than two years is sure to get truck operators talking. The knock against natural gas has traditionally been the availability of the fuel – or lack thereof – and the cost of the equipment. However, in his opening remarks at the Green Truck Summit, US Secretary of Energy Dr. Steven Chu pointed out natural gas supplier Clean Energy has promised to build 275 natural gas fueling stations by the end of this year. He said there will soon be a fueling station every 150 miles or so in the US, and natural gas trucks will have the capacity to travel up to 500 miles between refills.

As for the cost, Gordon Exel, vice-president and general manager Americas with Cummins Westport pointed out the cost of a natural gas engine is on par with the cost of a traditional diesel. It’s the fuel tanks that are to blame for the considerable up-charge, and Chu noted work is underway to develop lower-cost, higher-capacity tanks made of composite materials.

Vancouver, B.C.-based Westport Innovations recently announced a 10-year extension to its joint venture with Cummins, which will see it roll out a 12-litre natural gas engine within a year. Exel said the companies have already built test units of the 12-litre. The 9-litre ISL G has been enormously successful for Cummins Westport. The engine’s emissions are well below EPA-mandated NOx and particulate matter limits, performance is on par with diesel engines in every category but range.

“Fuel mileage is duty-cycle driven,” Exel said. “We say we’re 10% worse in fuel economy than a diesel compression ignition engine, but under load we’re very close. At high idle, that’s probably our weak spot.”

Ironically, however, the ISL G has made huge gains in transit bus operations, which is a notoriously high idle application. Since Cummins Westport natural gas engines are spark-ignited, fleets will have to replace the spark plugs regularly at a cost of about $50 to $60 a pop. However, Exel said that translates to a cost of about a penny or a penny and a half per mile, which is more than offset by the fuel savings.

“It gets lost when you look at it from a fuel savings perspective,” he said. “It gets lost; it’s background noise.”

Speaking of noise, the ISL G is about 10 decibels quieter than its diesel equivalent at idle, Exel added. The ISL G requires a different motor oil than the Cummins ISL diesel and fuel filters must be inspected daily. Besides that, there’s not a lot to differentiate between the diesel and natural gas ISL engines; there’s an 80% parts commonality Exel said. To calculate whether a transition to natural gas will deliver savings, Exel said fleets can easily work it out on the back of a napkin by calculating the up-charge, annual mileage and the current spread between gas and diesel prices.

Once you’ve decided to invest in natural gas trucks, the next issue is to source the fuel. Trillium’s Zobel advised fleets to “select a vendor based on reputation and customer service; low cost is not always the best value.”

Mistakes fleets have made include: relying on stations that take a half-hour or more to fill up a truck; sourcing gas from stations that don’t temperature-compensate their equipment, so the truck leaves the pump at less than capacity; signing on with unreliable providers who are frequently out of service; filling up at stations that don’t accept credit cards; and relying on filling stations that are not truck-friendly. Because natural gas fueling infrastructure is relatively cheap, fleets deploying multiple gas-powered trucks may have the opportunity to convince a supplier to build a fueling station on their own premises. Zobel also said fleets can consider building a private or public/private filling station of their own, or lease or even lease-to-own the fueling equipment.

If choosing to fuel up at their own terminal, fleets will have to consider the benefits of fast fill versus time fill infrastructure. Fast fill will fill a truck within minutes while time fill requires a truck to be plugged in overnight to be fueled up. There are cost savings to be had with the latter method if trucks are off-duty overnight, Zobel explained.

“Those are two options available at two different price points,” he said.

Finally, fleets transitioning to natural gas should be good neighbours and advise nearby residents, businesses and local first responders. The fuel is safe to use, experts advised, but its best to err on the side of caution and be up-front about its use. Training is available to first responders, so they can learn how to safely approach a natural gas-powered truck that’s been involved in an accident.

“First responders are concerned about all these new vehicles,” said Al Ebron, executive director of the National Alternative Fuels Training Consortium. “They don’t understand them. But word is getting out to them that they don’t have to be afraid of it and after they go through the training, they have not been concerned afterwards.”

Besides, Ebron added, “They have a safe track record. I’d rather have a natural gas cylinder in my car than the gasoline tanks we all ride around on.”