The fifteen-liter dual-fuel, diesel-natural gas engine may be ready to take to the highways, before the highways are ready for it.

Cummins Inc. announced on January 15 that it has paused development of its 14.9 liter ISX15 G natural gas-powered engine, citing the uncertain demand for such engines, in light of lagging infrastructure support development and the cost of on-board tanks.

Christy House, the On-Highway Marketing Communications Director for the engine manufacturer, says that “market timing uncertainty” has prompted the decision. Cummins introduced the ISX15 G in March of 2012, and expected to begin production later this year.

“While we believe natural gas power will continue to grow in the North American truck market, the timing of the adoption of natural gas in long haul fleets preferring fifteen-liter engines is uncertain,” House said. “We believe the adoption of natural gas in long haul fleets will be paced by a variety of factors beyond the engine, and include fuel tank technology and public fueling infrastructure.”

As an alternative to buying new natural gas power, conversion systems are available for installation on diesels in late-model trucks as well as in newly assembled glider kits. Conversion systems are dual-fuel, allowing a truck to run on both natural gas and diesel. But while natural gas may be a cheaper fuel for trucks, equipping a truck with fuel tanks is over half of the high cost of aftermarket natural gas conversion. And while natural gas fueling stations are spreading along America’s major arteries of commerce, they may have a long way to go before they can support widespread long-haul trucking.

House says Cummins plans to re-evaluate the future of the engine later this year. Cummins seems to be taking a cue from its partner in natural gas technology development, Westport Innovations. Westport discontinued its version of the fifteen-liter dual-fuel, diesel-natural gas engine in October of 2013, due to low sales. It plans to work more directly with truck manufacturers to develop natural gas technology.

The ISX15 G is a spark-ignition engine, similar in design to the smaller 11.9-liter ISX12 G that went into production in 2013. Asserting its commitment to natural gas, Cummins offers that “heavy-duty fleets desiring natural gas power currently have the option of the Cummins Westport ISX12 G, which is available in a wide range of heavy-duty truck OEMs.” While the “12G” provides up to 400 horsepower, it may not be powerful enough to get heavy tractor trailers over the mountains in western North America.

The 15G was only one of many projects that were on the drawing board at Cummins last year. Earlier in January, the corporation was honored with the 2013 Newsmaker of the Year award from Diesel Progress North American magazine. Cummins is a third-time recipient of the Newsmaker of the Year award, previously recognized in 2002 and in 2007.

“New engine platforms, integrated powertrains and all kinds of engine business news… Cummins was in the news all year,” according to publisher Mike Osenga. Cummins made the news by expanding its relationship with Navistar, cooperating with Eaton in developing the SmartAdvantage™ Powertrain, and introducing a wide range of engines.

In addition to development news, Cummins’ Jamestown Engine Plant in New York built its 1.5 millionth engine last summer.