Natural gas remains one of the most talked about subjects in the trucking industry of late, and that’s not likely to change anytime soon. There is now a fairly expansive line-up of viable natural gas vehicles available and the fuel remains plentiful and inexpensive when compared to diesel. But the early adopters have had mixed experiences with the equipment, including trailblazers Bison Transport and Robert Transport, who both were at the first-ever Natural Gas Vehicle Infrastructure Canada Conference held in Toronto Oct. 1-2.

Many of the first fleets to use natural gas are also getting into the gas distribution business, building fuelling sites on their own properties that they’re opening to the public in the form of commercial cardlocks. With that in mind, they have some good incentive to speak glowingly of the technology and to help build a market. That’s why I was so impressed to hear the candid – and sometimes less than glowing – reports from Trevor Fridfinnson, sr. vp., Bison and Yves Maurais, engineering manager with Robert. It’s not that they’re down on gas – they just want their peers to make informed decisions before jumping in. So here are some of the highlights of their presentations:

Bison has 15 LNG Peterbilts, which have been pulling Twin-53s between Calgary and Edmonton since the start of the year. Robert now has 115 LNG Petes, which have been in service for two years. Bison envisioned a two-year payback on their gas trucks, which Trevor admitted is “not going to be possible…Where it ends up, I think that remains to be seen because we think there are further efficiencies that can be drawn out of this particular model, but suffice it to say, it is an extended timeframe.”

So what went wrong? In Bison’s case, fuel mileage hasn’t been as good as they had hoped. The gas trucks are getting about 5 mpg (in an LCV application, remember) compared to 6 mpg for the diesels. This is in part because the LNG tanks require a longer wheelbase, and of course a larger trailer gap, which hurts fuel economy. Range is about 450 miles between fills, well shy of the 550 Bison was hoping for. But the real killer has been maintenance costs, which are tracking at 7-8 cents per mile, about double the diesels. “These (LNG) trucks have had an inordinate amount of issues,” Trevor said. While he said Bison remains committed to its natural gas project, Trevor was non-committal about adding more LNG trucks. Enthusiasm, even among customers, has waned as a result of the disappointing results.

Robert’s Yves Maurais had a better story to tell. Robert’s LCV tractors are getting fuel mileage that’s about equal to the EPA07 Cummins ISX engines the 15L Westport GX engines were built upon. One surprise discovery for Robert was that the diesel to nat-gas consumption rate was about 10% diesel, or about double what they were expecting. (The Westport engine is compression ignited, and requires a burst of diesel to initiate the combustion process). The big complaint from Yves was the weight; the trucks were overweight on the steer axle by US standards the first time they were filled with fuel!

Another problem encountered by Robert was that the in-cab methane detectors sucked power. Not to be deterred, the company’s now installing solar panels on the cab roof to power the methane detectors. One thing Yves pointed out, which should come as good news to Trevor and others who are earlier in the deployment process, is that the natural gas trucks seemed to have a longer break-in period. Yves thinks the natural gas trucks will achieve fuel economy equal to their diesel counterparts, it just takes longer. “These trucks have been in service now for 18 months to two years, so we’re figuring out that the break-in period of these engines is a lot longer than a regular diesel engine,” he said. “It could be up to 200,000 kms before we get optimal fuel consumption.” Go here for a more detailed report from the conference.