Diesel has powered off-highway machinery for generations, but rising emissions pressure and tightening regulations are reshaping expectations for how these machines will run in the years ahead. A comprehensive review of 115 studies published over the past 15 years offers a data-driven look at where alternative powertrains for off-highway vehicles stand today, and where the technology is headed next. The research covers five main categories: hybrid, full-electric, biofuels, biogas, and hydrogen, across forestry, industrial, construction, and agricultural machinery.
Hybrid and Full-Electric Lead the Pack
Among all the options studied, hybrid and full-electric solutions consistently showed the greatest potential to replace diesel engines. Full-electric powertrains can achieve zero local emissions during operation, while hybrid and full-electric technologies posted the highest Technology Readiness Levels of any category, reaching 6.9 to 7.4 in industrial machinery. Real-world testing backs this up: hybrid systems have cut fuel consumption in bulldozers by up to 28 percent, reduced total energy use in electric-hybrid forklifts by 55 percent, and improved efficiency in excavators by as much as 48 percent.
Full-electric machines bring their own advantages, particularly a more compact motor and the ability to fine-tune torque and speed more precisely than a conventional diesel engine. Cable-charged equipment, such as electrified cranes, has shown energy consumption reductions of 30 to 47 percent, making it especially well suited to machines that operate within a fixed area. Still, battery reliability and cost remain the central hurdles for wider adoption of alternative powertrains in off-highway vehicles, especially in cold-weather conditions where battery performance and disposal present ongoing challenges.
Biofuels, Biogas, and Hydrogen: Lower Emissions, Lower Readiness
Renewable fuels tell a different story. Biofuels such as rapeseed oil have delivered fuel consumption up to 8 percent lower than diesel, alongside notable cuts to nitrogen oxide, carbon dioxide, and particulate matter emissions. Biogas has shown similarly strong results, with one agricultural tractor demonstrated to increase torque by up to 40 percent while cutting total lifecycle emissions by roughly 80 percent. Hydrogen, meanwhile, produces zero emissions at the point of operation and has improved efficiency in dump trucks by close to 29 percent in early testing.
Despite these gains, biofuel, biogas, and hydrogen powertrains for off-highway vehicles remain earlier in their development curve. Technology Readiness Levels for biogas in construction machinery, for example, sit as low as 2.5, and hydrogen adoption is currently limited mostly to smaller equipment, such as forklifts, due to high fuel cell costs and constrained production capacity. Expanding these fuels will depend heavily on scaling up local production and bringing down manufacturing costs.
What Comes Next
Looking ahead, the outlook favors continued momentum for electrification, particularly in industrial settings where charging infrastructure is easier to establish and operating areas are more contained. Forestry and agricultural machinery face a tougher path, since remote work sites make charging access and fuel distribution more difficult. That gap is expected to keep hybrid solutions relevant in these segments for longer, serving as a practical middle ground between conventional diesel and full electrification.
Future research priorities are clear: improving battery reliability and compactness, scaling up biofuel and biogas production, and lowering the cost of hydrogen fuel cells and distribution. As these pieces fall into place, the review anticipates a steady shift away from diesel across nearly every off-highway segment, with the pace of change varying by machine type and operating environment.
For manufacturers and fleet operators alike, the message is consistent: alternative powertrains for off-highway vehicles are no longer a distant possibility but an active, fast-developing field. Understanding the trade-offs between hybrid, electric, biofuel, biogas, and hydrogen options will be essential for planning fleet investments over the next decade.
To discover the latest innovations and trends in zero-emissions off-highway machines, meet with solution providers and hear talks from industry leaders, book your place to attend the 8th Design And Development Of Zero-Emissions Off-Highway Machinery Summit, taking place February 24-25, 2027 in Chicago, Illinois.
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.
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