Skip to content

California Fleets Fueled With Bio-CNG Achieve Carbon-Negativity For Second Straight Year

Bio-CNG Below Zero Again with Annual Average Carbon Intensity Score of -44.4 gCO2e/MJ for 2021

Washington, DC – Natural Gas Vehicles for America (NGVAmerica) and Coalition for Renewable Natural Gas (RNG Coalition) today announced that California fleets fueled with bio-CNG achieved carbon-negativity last calendar year for the second straight year.  

Ninety-eight (98) percent of all on-road fuel used in natural gas vehicles in California in 2021 was renewable natural gas (RNG). According to data from the California Air Resources Board (CARB) the annual average carbon intensity score of bio-CNG in that mix was -44.4 gCO2e/MJ.1

Moreover, the carbon intensity of California’s bio-CNG remains well below zero today.  Data from Q1 2022 puts the carbon intensity average of bio-CNG at -61.4 gCO2e/MJ.  Q2 2022 data is expected to be released at the end of this month.2

“For the second straight year, California fleets fueled with bio-CNG achieved carbon-negativity in their 2021 transportation operations,” said NGVAmerica President Dan Gage.  “And since 98 percent of natural gas dispensed in California for use as a motor fuel is from renewable sources, California natural gas vehicle (NGV) fleets consistently achieve a zero-carbon footprint and virtually eliminate criteria pollutant emissions that contribute to asthma, heart disease, and poor air quality.”

In addition to their negative greenhouse gas (GHG) emissions, ultra-low NOx medium- and heavy-duty RNG-fueled trucks and buses perform at levels that are 95 percent below the federal nitrogen oxide (NOx) standard and 98 percent below the federal particulate matter (PM 2.5) standard.3

“RNG facilities address methane emissions from society’s inevitable waste streams, mitigate the environmental impacts of those emissions and convert captured methane into domestic, renewable, clean fuel and energy,” stated Johannes Escudero, Founder & CEO of RNG Coalition. “These numbers highlight the critical role that RNG is playing in decarbonizing the medium- and heavy-duty transportation sectors today.” 

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.  

RNG use as a transportation fuel in California grew 163 percent over the last five years.  NGVAmerica and RNG Coalition report that in 2021 a total of 178.37 million gallons (DGE)4 of natural gas were used as motor fuel in the state.  Of that, 174.28 million gallons (DGE) were from renewable sources.5

Data from CARB’s Low Carbon Fuel Standard program confirms that bio-CNG remains the only net-zero carbon motor fuel in California’s alternative motor fuel portfolio, which includes ethanol, biodiesel, renewable diesel, bio-CNG, bio-LNG, electricity, alternative jet fuel, and hydrogen.

Aggressive decarbonized transportation goals over the next decade will only be achieved by prioritizing the transition of heavy-polluting, heavy mileage commercial fleets to cost-effective carbon-negative solutions like RNG trucks that are commercially available now, accruing and compounding significant clean air and carbon reductions today.

Details of today’s report – including graphics – can be accessed at: NGVAmerica’s website HERE and RNG Coalition’s website HERE

Dan Gage (NGVAmerica)
Lesley Dalton (RNG Coalition)

1 California Air Resources Board, Low Carbon Fuel Standard Program, Certified Fuel Pathways
2 California Air Resources Board, Low Carbon Fuel Standard Program, Certified Fuel Pathways
3 Cummins, Inc.
4 DGE = diesel gallon equivalent.
5 Total Natural Gas in Transportation Figure derived from U.S. EIA’s Annual Energy Outlook (2022) and RNG numbers derived from U.S. EPA Renewable Fuel Standard Program reporting with adjustments made based on fueler member reporting.



NGVAmerica is a national trade association of sustainability solutionists and experts in the clean transportation field.  Our roughly 200 members are dedicated to the development of a growing, profitable, and sustainable market for vehicles, ships and carriers powered by natural gas and biomethane.  NGVAmerica member companies produce, distribute, and market natural gas and biomethane across North America, manufacture and service natural gas vehicles, engines, and equipment, and operate fleets powered by clean-burning gaseous fuels.  Find out more at:

Coalition for Renewable Natural Gas is the non-profit association of renewable natural gas in North America. Membership is comprised of 360+ companies, labor organizations, municipalities, colleges, and universities. Find out more at: