May 6, 2026. The Transport Project (TTP) announced that 94 percent of all on-road fuel used in natural gas vehicles in calendar year 2025 was renewable natural gas (RNG), surpassing the previous year’s record-breaking level.
Captured above ground from organic material in agricultural, wastewater, landfill, or food waste, RNG can produce carbon-negative results when fueling on-road vehicles like short- and long-haul trucks, transit buses, and refuse and recycling collection vehicles. California Air Resources Board data confirms that the annual average carbon intensity (CI) value of California’s bio-CNG vehicle fuel portfolio in its Low Carbon Fuel Standard (LCFS) program for 2025 was carbon negative and below zero at -198.32 gCO2e/MJ.
RNG use as a transportation fuel grew 13 percent over 2024 volumes, up 94 percent from 2021 levels. TTP reports that in 2025 a total of 806 million gallons (GGE) of natural gas were used as motor fuel. Of that, 755 million gallons (GGE) were from renewable sources.
“The Transport Project members continue to work to further decarbonize America’s natural gas motor fuel, introducing increasing amounts of RNG into the national distribution network to advance fleet sustainability goals,” said Dan Gage, President of The Transport Project. “CNG trucks in the United States run on domestic RNG today. And RNG is a reliable, proven, more affordable and price-stable alternative to diesel especially given current global events.”
RNG use as a motor fuel in 2025 displaced 11.01 million metric tons of carbon dioxide equivalent (CO2e). Put into perspective, RNG motor fuel use last year:
- Lowered greenhouse gas emissions, equivalent to removing the GHG from over 28 billion miles driven by the average passenger car;
- Eliminated CO2 emissions, equivalent to removing CO2 emissions from over 2 billion gallons of gasoline consumed; and
- Sequestered carbon, equal to growing over 182 million tree seedlings for ten years, or over 11 million acres of U.S. forests for one year.