Carbon negative bio-LNG could gain traction in the U.S.

While compressed renewable natural gas (C-RNG) also known as bio-CNG gets plenty of attention for having the lowest carbon intensity (CI) value of all transportation fuels, you don’t hear much about the fuel in second place: liquified renewable natural gas (L-RNG) also known as bio-LNG. 

According to CARB, bio liquified natural gas (LNG) is second only to compressed renewable natural gas (RNG) in terms of its negative carbon intensity values.California Air Resources BoardThe most recent CI fuel values published this week by the California Air Resources Board (CARB) show bio-CNG clearly in the lead with its best score at -600 followed by bio LNG with -400. Both fuels get negative scores since they're obtained from methane which CARB and the EPA consider to be much more devastating to the ozone layer than carbon dioxide.

But according to the 2023 State of Sustainable Fleets report from Gladstein, Neandross & Associates, it’s compressed RNG that’s largely favored among fleets.

“Fleets have fully replaced their fossil-based CNG with renewable natural gas in California during the past two years, and growth is strong nationally,” states the report, which was published earlier this month.

Industry experts say renewable LNG is more widely used in Europe and that its prospects in the U.S. are mostly limited by availability. 

“It’s all about the infrastructure for LNG fueling, storing, etc. Generally the industry moved to mostly CNG,” said Dave King, Cummins North American on-highway product manager for natural and renewable gas engines. “CNG vehicle fuel systems have improved for packaging on the vehicle. The fuel does not weather in the vehicle system. And fueling infrastructure grew for CNG. For CNG you can put a compressor station on a pipeline and have a fast fill CNG station. For LNG you have to liquify the gas, transport by tanker vehicle, etc., and have cryogenic storage at the refueling facility.”

Eric Bippus, executive vice president at Hexagon Agility, also doesn’t see bio-LNG overtaking bio-CNG in the U.S. and noted that most of Hexagon's LNG customers are in Europe. However, he thinks it's possible the fuel may gain some ground in the U.S. thanks to its negative carbon value, increased energy density and Cummins new 15-liter X15N,  which can run on either compressed or liquified natural gas. Hexagon displayed its Bio LNG Cryoshelter tank earlier this month at the Advanced Clean Transportation Expo in Anaheim, California where Bippus said it attracted attention from both European and U.S. fleets.