The transition to zero emissions technology in America’s truck and bus fleets continues, albeit slowly, with battery-electric power now fueling 7% of transit buses, 0.4% of school buses, and 0.1% of commercial trucks, according to the Engine Technology Forum (ETF). Despite this progress, traditional fuels like gasoline, diesel, natural gas, and propane remain dominant.

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ETF’s analysis of S&P Global Mobility TIPNet data of US Commercial Vehicles as of December 2023 shows that 99.9% of commercial vehicles, from delivery trucks to 18-wheelers, are still powered by internal combustion engines. Diesel leads the pack at 76%, followed by gasoline at 22%, with natural gas and propane trailing. However, advanced near-zero emissions diesel technology is on the rise, showing a 4% increase over 2022.

Emerging zero-emissions technologies, such as battery electric and fuel cell vehicles, currently make up a small fraction of the fleet. Electric vehicles are more common in transit buses (7.8% EV), while electric-powered commercial trucks (Class 3-8) number over 20,000 units, and school buses about 2,000 units.

As of December 2023, 61% of all commercial diesel trucks on the road were model year 2010 or newer, a 4% increase from 2022. These newer models feature advanced emissions controls, resulting in near-zero emissions. California leads the nation in the adoption of advanced diesel technology, with a 13.3% increase compared to 2022.

“Advanced diesel and natural gas technologies are helping communities experience cleaner air and lower greenhouse gas emissions,” said Allen Schaeffer, Executive Director of the Engine Technology Forum. “From 2010 through 2030, these newer diesel trucks will save approximately 1.3 billion tons of carbon dioxide emissions, 130 billion gallons of fuel, and significant amounts of particulate matter and nitrogen oxide emissions.”

Renewable fuels are also playing a growing role. In 2023, over 2.8 billion gallons of renewable diesel and 1.9 billion gallons of biodiesel were consumed. Renewable diesel production capacity could reach 5.9 billion gallons per year by the end of 2025. Additionally, more than 79% of the natural gas used in transportation in 2023 was renewable natural gas (RNG), with California achieving an average carbon intensity score of -126.42 grams of CO2 equivalent per Mega Joule for Bio-CNG/RNG, the lowest of any clean fuel option.

Schaeffer emphasizes the importance of continued investment in new technology internal combustion engines (ICE) to ensure progress toward clean air and climate goals. “Replacing older vehicles with new advanced ICE technology delivers substantial benefits. It would take more than 60 current generation diesels to equal the emissions of a single heavy-duty diesel truck built in the 1990s.”

Battery electric and fuel cell vehicles currently make up only 0.1% of the commercial truck population. Of the largest trucks (Class 8), 97% are powered by diesel. For diesel trucks in Classes 3-8, 61% are equipped with the latest emissions technology.

California leads in the adoption of EV technology in commercial trucks and buses, followed by states like Pennsylvania, Washington, New York, and Massachusetts. Indiana has the highest percentage of advanced generation diesel trucks, with 82% of Class 8 trucks being model year 2010 or newer.

Schaeffer concludes, “While electric and hydrogen options develop, internal combustion engines will dominate our goods movement and public transport sectors for decades. Continued innovation and the expansion of renewable fuels will ensure ongoing progress and reduce the greenhouse gas emissions burden in the future.”

Key Findings:
– The newest generation of advanced diesel trucks (2010+ MY) outnumber electric trucks (any model year) by 367:1.
– For every electric Class 8 truck, there are 240 new generation advanced technology diesel trucks.
– For every electric transit bus, there are more than 5 new generation advanced technology diesel buses.
– For every electric school bus, there are 155 new generation advanced technology diesel buses.