The trucking industry is heaving its way towards a new direction. Fuel prices are rising, emissions laws are tightening, and fleets need cleaner, cost-effective alternatives to diesel.
For this reason, Cummins built its X15N engine.
According to the brochure, it is a powerful 15-liter natural gas engine designed for long-haul trucking. But what really seems to set it apart is its ability to run on renewable natural gas (RNG)—a fuel that is said to be able to slash emissions by up to 97% all while still keeping performance on par with diesel.
Never heard of RNG before?
RNG is one of the most overlooked forms of fuel out there. It is made from organic waste, like manure from dairy farms or food scraps. Instead of letting methane escape into the air—a gas that’s far worse for the climate than CO2—RNG captures and converts it into clean energy. In fact, some sources say RNG-powered trucks can achieve negative emissions, meaning they remove more carbon from the atmosphere than they produce.
With nearly 70% of commercial natural gas trucks in the U.S. already using RNG, it’s clear the industry is moving in this direction. But to make the transition successful, trucking companies need an engine that can deliver power, efficiency, and reliability—and that’s exactly what the X15N was built for.
This engine offers diesel-like performance without the downsides
Cummins designed the X15N to match and maybe even exceed the performance of traditional 15-liter diesel engines. It delivers between 400 to 500 horsepower and up to 1,850 lb-ft of torque, making it ideal for heavy-duty, long-haul trucking. Plus, it’s hundreds of pounds lighter than previous diesel models, meaning trucks can carry more cargo and maximize profits.
And it’s not just numbers on paper—this engine has been tested in real life. In real-world trials, the X15N successfully hauled heavy loads up Loveland Pass in Colorado, which is a brutal 12,000-foot climb. It really proved its strength and durability out here. Cummins has also logged over 1.5 million test miles in the U.S., with another 3.5 billion miles of experience from similar engines used in China.
Cummins says that the X15N is up to 10% more fuel-efficient than its predecessor, the ISX12N. And because it runs on natural gas instead of diesel, it eliminates the need for diesel exhaust fluid (DEF), which will ultimately cut down on maintenance costs.
Refueling is also easier than ever. North America already has over 1,500 compressed natural gas (CNG) stations, and RNG can use the same infrastructure (eliminating the hassles that this type of fuel is facing). Some fleets are even building their own private fueling stations, allowing them to lock in stable fuel prices instead of dealing with market fluctuations.
It’s a reliable engine that has been built for the future
Cummins understands that uptime is everything in trucking. That’s why the X15N comes with advanced digital tools like:
- Remote Monitoring – Detects issues before they cause breakdowns.
- Over-the-Air Updates – Keeps the engine running at peak efficiency.
- Predictive Diagnostics – Helps fleets plan maintenance before problems occur.
These features are meant to keep trucks on the road longer and out of the repair shop.
Big fleets are already making the switch
Major trucking companies are already buying the X15N. Over 40 fleets have placed orders, and surprisingly, 30% of them have actually never used natural gas before.
Analysts predict that by 2030, around 20% of Class 8 trucks could run on natural gas.
To meet demand, Cummins’ says its Jamestown Engine Plant is ramping up production. Right now, Kenworth and Peterbilt are offering trucks with the X15N, and but the company says that more manufacturers are expected to follow in 2025.
The X15N gives fleets a practical way to cut down on their immediate emissions today (just like this engine does)—without sacrificing performance or reliability. Whether powered by CNG or RNG, this engine is a major step toward a cleaner, more sustainable future for trucking.
