New data from the seventh annual State of Sustainable Fleets report reveals that fleet operators are distributing their equipment bets across multiple fuel types rather than concentrating orders on any single technology, as policy uncertainty and tariff pressure suppress overall vehicle purchasing.

Battery-electric medium-duty and heavy-duty truck registrations rose 21% in 2025, and fleets running them report lower operating costs than the vehicles they replaced. However, hydrogen fuel cell trucks remain commercially unviable for most operations, with fuel costs averaging $18.86 per kilogram after incentives, an 89% to 135% premium over diesel. Industry analysts say hydrogen must reach $8 to $10 per kilogram to compete on total cost of ownership.

Natural gas has become the near-term alternative of choice. The Cummins X15N 15-liter natural gas engine finished its first commercial year with 71% of operators reporting savings over diesel. Leading fleets including Walmart, Amazon, UPS, FedEx, and Werner placed X15N orders during its debut year.

Propane adoption has quietly expanded. The market burned an estimated 1.8 million more gallons in 2025 than the prior year. More than 23,000 propane school buses now serve 1,100 school districts across 49 states, with many Midwest districts locking in fuel prices between $1.32 and $1.90 per gallon equivalent. California's transportation sector leads in renewable diesel adoption, displacing nearly three-quarters of conventional diesel used in state transportation in 2024.

Source: FreightWaves / State of Sustainable Fleets 2026 -- https://www.freightwaves.com/news/state-of-sustainable-fleets-2026