On a recent episode of Truck Tech, Alan Adler interviewed natural gas technology leaders Hexagon Agility, Cummins, and Kenworth who have partnered for more than a decade to ensure RNG heavy-duty trucks are spec’d right for duty cycle and operation, resulting in diesel-like performance.
In the debut podcast, Alan Adler sits down with Sarah Abernethy of Kenworth, Puneet Jhawar of Cummins, and Eric Bippus of Hexagon Agility to explore how others in the heavy-duty truck space can make RNG Class 8 trucks a reality for their fleets.
Recent rulemaking by the Environmental Protection Agency (EPA) on Phase 3 emissions mandates stronger standards in reducing greenhouse gas emissions. Part of the Phase 3 final rulemaking requires a greater total percentage of certain fleet segments to be made up of zero-emissions vehicles. The good news, according to the OEM, trucks equipped with the Cummins’ X15N engine are set to meet stringent EPA and California Air Resources Board (CARB) regulations for model years 2024 and 2027.
Adler said industry analysts estimate that RNG could grow to power nearly 20% of all heavy trucks in North America. Leading fleets, including UPS, Frito-Lay, Wegmans and others, are betting big on RNG to reduce emissions and fuel costs.
RNG is a biofuel produced from organic materials such agricultural, wastewater, landfill, or food waste and can produce carbon-negative results when fueling on-road heavy-duty trucks.
For Cummins, the engine maker and Hexagon Agility, a leading provider of RNG fuel systems, the RNG opportunity led to expanded relationships with various OEMs, dealers and long-haul heavy-duty fleets.
Enter the X15N, bigger bore with bigger potential
Kenworth Class 8 T680 and T880 models equipped with X15N commenced production late August 2024. Class 8 trucks have higher powertrain and torque requirements that older RNG engines couldn’t meet. The previous generation of natural gas engines by Cummins, the ISX12N, released in 2018, boasted 320-400 horsepower and 1,150-1,450 lb.-ft of torque. The recent release of the X15N rated up to 500 horsepower and 1,450-1,850 lb.-ft of torque reached parity with an internal combustion diesel engine.
Sarah Abernethy, marketing manager at Kenworth Powertrain, told Adler: “What’s exciting about the X15N is that you shouldn’t feel too much difference between your diesel truck and an X15N. This engine is designed to have diesel-like performance, which is a next step in natural gas technology, so that’ll give drivers the performance and power and all that they need to do the heaviest loads and all the jobs that they’ve been doing with a larger bore 15-liter diesel engine with a natural gas engine.”
A big bore engine also means a bigger market share, but it must work with existing power trains. Abernethy said, “We’ve mated this engine to the Endurant HD 12-speed transmission. Cummins and Eaton have worked really hard to make sure that the shift points and the drivability of the trucks have been tuned to the point of what drivers are expecting from a 15L.”
An added benefit of the X15N engine is the ability to meet both EPA and CARB regulations for model year 2024 and 2027 trucks. Abernethy noted that customers with environmental, social and governance goals are now able to tackle loftier emissions reduction goals.
With fuel systems from Hexagon Agility, class 8 trucks equipped with the X15N get up to 1,200 miles range. This means RNG trucks have parity with diesel in both power and range. Because RNG fuel systems are installed behind-the-cab or rail mounted, Abernethy said that key considerations for the specifications of a natural gas truck compared to a diesel engine, is to understand your wheelbase needs, body layout, frame space and range.
She adds that having conversations with dealers is important, as fleets have various configuration needs for their trucks.
A fuel-agnostic platform takes the HELM
For Cummins, innovation comes in the form of a fuel-agnostic platform called HELM: higher efficiency, lower emissions and multiple fuels. The system works by using a common engine architecture below the head gasket, with the components of various fuel times existing as a platform above the head gasket.
When looking at the X15N engine, Puneet Jhawar, former general manager of alternate fuels at Cummins, told Adler it has generated tons of interest and will begin full regular production in a few months, first with the PACCAR family, which includes both Kenworth and Peterbilt. Later it will come to Freightliner. “2025 we should see the Freightliner coming out as well,” Jhawar said.
Jhawar felt now was the time to bring the engine to the U.S. market.
“We’ve got over 40,000 installations globally on this platform and it has run about 2 billion miles, and the feedback has been a resounding success,” he said. “The engine itself in the U.S. has run about a million miles on the road in addition to the test units.”
Jhawar added trucks powered by natural gas have 90% lower nitrogen oxide emissions than new diesel trucks, depending on the type of natural gas used, whether compressed natural gas (CNG) or RNG.
Details fleets need to consider when switching to RNG
For fleets looking to switch from diesel to RNG, the first step is to understand fueling infrastructure and range . Looking at the vehicle from the eyes of a fleet owner, Eric Bippus, EVP of sales and systems development at Hexagon Agility, showcased a Kenworth T880 sleeper truck. It included a 175-diesel-gallon-equivalent (DGE) behind-the-cab and dual 30 DGE side mounts, which can also be swapped for 45-DGE side-mount options. The roughly 265-DGE enables approximate 1,200-mile range depending on payload and terrain.
“The early days of natural gas back around 2012, 2013 and 2014 was all about the return on investment and what is the price difference between diesel and compressed natural gas. Today that ROI and price difference is an important piece for fleets which are for-profit businesses and must be able to deploy technology at scale, which also has a payback.”
Bippus added, “It’s no longer just about the ROI, it’s about, ‘Hey, I can really decarbonize my heavy-duty fleet with a viable option.”
The upcoming Phase 3 emissions rules from the EPA set to go into effect in 2027 are expected to close the selling gap between a RNG/CNG versus a diesel truck. Part of this is due to the added emissions requirements on diesel engines, which according to Bippus could add $25,000 to $40,000 to the cost.
For Hexagon Agility, there’s growing excitement based on user feedback. That brings the opportunity for more market penetration in a diesel truck market that Bippus estimates is 97% diesel for the roughly 350,000 vehicles produced each year. Even a market penetration of 10% could see 35,000 to 50,000 RNG/CNG trucks going into the market every year.
To learn more about Hexagon Agility, visit www.hexagonagility.com.
