Cummins: Natural Gas Engines Outperform Diesel on Cost, Emissions, and Maintenance
Natural gas engines provide heavy-duty fleets with 13–17% lower greenhouse gas emissions, quieter operation, simpler maintenance, and consistently lower fuel costs compared to diesel, according to Cummins.
13–17%
27%
Consistently lower than diesel since early 2000s
What Happened
Cummins has published a detailed comparison of natural gas and diesel engines for heavy-duty commercial fleets, highlighting natural gas as a strong alternative. The company notes that natural gas engines deliver similar performance and drivability to diesel but are quieter, require simpler maintenance, and offer more convenient refueling options. Fuel costs have been consistently lower and more stable for natural gas since the early 2000s, decoupled from oil price swings.
- Often quieter
- Standard and time-fill overnight
- Simple, maintenance-free exhaust system
13–17%lower well-to-wheel
Compared to diesel when using virgin natural gas; RNG can achieve sub-zero net emissions.
- Fast-fill: uses a compressor and storage system; refuels in about the same time as diesel.
- Time-fill: compresses gas directly into vehicle cylinders overnight; drivers connect and leave without waiting.
Why this matters
For fleet managers, switching to natural gas can cut fuel and maintenance costs while reducing environmental impact, with renewable natural gas offering the potential for net-zero emissions.
Terms in This Story
- Renewable Natural Gas (RNG)
- Biogas captured from organic waste such as animal manure or landfill decomposition, which can achieve sub-zero net greenhouse gas emissions when used as vehicle fuel.
- Well-to-wheel emissions
- A measure of greenhouse gas emissions from the entire fuel lifecycle, including extraction, production, and combustion in the vehicle.
- Exhaust aftertreatment
- A system of sensors, filters, and converters used to reduce pollutants in engine exhaust, typically required on diesel engines but not on natural gas engines.
- Compressed natural gas (CNG)
- Natural gas that is compressed to high pressure for storage and use as a vehicle fuel, typically used in heavy-duty trucks.
Summarised from the linked release; details can be imperfect — always verify against the original source.