Natural Gas Infrastructure Is Scaling Fast for HD Fleets

Nopetro Energy stresses that RNG is a drop-in fuel that integrates seamlessly with existing CNG infrastructure, eliminating the need for large-scale system overhauls.

August 1, 2025

Jorge Herrera

Nopetro Energy says it currently operates and maintains 15 RNG fueling stations, serving municipal fleets and some of the world’s biggest companies. (Nopetro Energy)

A significant shift is transforming the heavy-duty transportation sector: the rapid advancement of natural gas and renewable natural gas (RNG).

Engineers and fleet designers face a real-world challenge: deploying clean, reliable fuel systems. Natural gas, particularly RNG, is answering that call. Backed by engineering breakthroughs and nationwide infrastructure growth, this solution is no longer a future consideration, it’s ready now.

The current state

Natural gas engines have evolved rapidly in recent years. While they have long been used in transit and refuse fleets, they lacked the power and range for over-the-road heavy-duty trucking.

The latest generation of 15-liter engines now offer the torque, durability and operational range needed for Class 8 trucks, while delivering both a lower total cost of ownership and significantly reduced emissions compared to diesel. For engineers looking for clean fuel solutions, this marks a turning point.

Most recently, Cummins started full production of the X15N natural gas engine. It is the first 15L natural gas engine designed with flexibility to perform across a range of heavy-duty applications, including haul line and vocational. It also is designed to meet the demanding performance standards of Class 8 fleets while offering significantly lower emissions and operating cost profile.

Prior to moving into full production, the X15N was extensively tested by some of North America’s largest and most-demanding line-haul, regional haul and vocational fleets under some of the toughest operating conditions. Early feedback showed its durability and diesel-like performance, representing a significant milestone in sustainable fleet performance.

RNG is surging

Medium- and heavy-duty trucks represent approximately 23% of the GHG emissions in the U.S., according to the Inventory of U.S. Greenhouse Gas Emissions and Sinks 1990-2022. The hauling capacity and distance necessary for heavy-duty transportation burns a lot of energy with very few options for clean alternatives – at least until now.

At RNG fueling stations, biogas sourced from landfills, farms and wastewater treatment plants are cleaned and compressed for use in heavy-duty vehicles. This process makes RNG a drop-in fuel that integrates seamlessly with existing compressed natural gas (CNG) infrastructure, eliminating the need for large-scale system overhauls.

While the batteries of electric and hydrogen vehicles weigh them down and significantly limit their range, RNG vehicles can perform the same as diesel vehicles in terms of range, refueling time and reliability. Heavy-transportation and power-generation carbon emissions can both be reduced by up to 400% when using renewable natural gas. Plus, RNG supply has surged 400% since 2018, according to a McKinsey report, with 44% more projects in the pipeline this year, the Coalition for Renewable Natural Gas announced.

Fast refueling and long range are just a couple reasons natural gas is an ideal energy source for trucking, transit buses, municipal fleets and waste collection vehicles. Natural gas, including RNG, is compatible with existing infrastructure across the country, while battery-powered vehicles require the expensive and timely installation of charging stations. Natural gas is more cost-effective than diesel and electric, and it generates long-term savings on maintenance.

Corporations benefit as well. RNG can help meet sustainability goals without sacrificing efficiency. A recent Executive Order is also prioritizing natural gas as part of the country’s clean energy infrastructure strategy, and additional proposed bipartisan legislation like the Renewable Natural Gas Incentive Act of 2025 is supporting the future of RNG.

Conclusion

CNG/RNG are commercially viable, scalable and emission-reducing solutions that are available now. While other energy sources, especially clean alternatives, are restrictive in their limited use, technological and socioeconomic factors have allowed CNG/RNG to become an alternative that does not sacrifice low-cost and efficiency. For engineers planning long-term fueling in

Jorge Herrera is CEO and co-founder at Nopetro Energy , based in Miami. He wrote this article for SAE Media.