Petroleum-powered internal combustion engines (ICE) are widely used in off-highway vehicles, using fuels such as diesel or gasoline. However, ICEs can use alternatives to traditional liquid fossil fuels that can be low-carbon or carbon-neutral, helping off-highway machinery meet global sustainability goals and not contribute to the pollution problem often faced by large machinery.
Alternative fossil fuels such as compressed natural gas (CNG) and liquid petroleum gas (a mix of propane and butane) have a lower emission factor than gasoline and diesel. Burning a certain amount of natural gas or propane will release less CO2 than burning the equivalent amount of gasoline or diesel. Off-highway vehicles operating on oilfields can use unwanted natural gas as an alternative to diesel for the mechanical drives, saving money, reducing emissions, and helping secure the fuel supply.
Renewable diesel, biodiesel, ethanol and biogas are obtained from energy crops or from organic waste. Biogas is fully interchangeable with natural gas and can be injected into natural gas pipelines or used on its own. Hydrotreated Vegetable Oil (HVO) is obtained by processing lipids such as vegetable oil, tallow or used cooking oil, which is made of paraffinic hydrocarbon. The fuel is derived from the same feedstocks used to produce biodiesel. However, instead of using the transesterification process, HVO is produced via the hydrotreated process. HVO is sometimes referred to as renewable diesel, or green diesel.
Advances in chemical engineering and other disciplines have also made it possible to synthesise methane, hydrogen, diesel and more from non-fossil feedstock such as carbon dioxide (CO2) and water using renewable electricity. These synthetic fuels are sometimes known as e-fuels.
Biofuels release the carbon which was taken from the atmosphere by the crops from which they are made, becoming net-CO2 free fuels. Switching to CNG or LPG can result in significant CO2 reductions, despite being fossil fuels. Using a fuel with a greater ethanol or biodiesel content or full conversions to biodiesel, HVO, ethanol, renewable natural gas, hydrogen, or an e-fuel may also be an option. Clean-burning fuels also have the benefit of not requiring systems to remove non-carbon emissions, making work environments such as underground mines far safer as well as cutting costs on expensive equipment and meeting sustainability goals.
Alternative fuels can be cheaper than fossil fuels, natural gas, for example has been consistently cheaper than gasoline and diesel when measured on a gasoline gallon equivalent basis. In addition to being low, the price of natural gas is also stable over time.
Additional benefits include:
- Shelf life: Unlike gasoline and diesel, natural gas and propane have an unlimited shelf life, as do hydrogen and ammonia-based e-fuels. This is also true of several newer biodiesel and synthetic diesel formulations, which can last up to 10 years.
- Environmental compatibility: Biodiesel and renewable diesel are also biodegradable, non-toxic and produce less fumes. LPG and natural gas are not likely to result in any soil or water contamination if spilled, since they would simply vaporize.
- Reduced maintenance needs: Natural gas and propane tend to burn cleaner than liquid fuels. A lesser amount of soot thus makes its way into the engine’s oil. Some operators take advantage of this by extending oil change intervals. When a large fleet of vehicles is involved, this can easily result in a savings of tens of thousands of dollars or more.
- Performance: Biodiesel and ethanol blends also have higher cetane and octane ratings than unblended diesel or gasoline, providing improved performance and acceleration.
To discover the latest innovations and trends in zero-emissions off-highway machines, meet with solution providers and hear talks from industry leaders, attend DZOMUSA – the 7th Design and Development of Zero-emissions Off-highway Machinery Summit taking place in Louisville, Kentucky, USA on December 10-11, 2025.
For more information, visit our website or email us at info@innovatrix.eu for the event agenda. Visit our LinkedIn to stay up to date on our latest speaker announcements and event news.
