The focus on clean energy is mostly monopolized by sources like solar, wind power, and so on. An often overlooked power source is Renewable Natural Gas (RNG), a purified form of biogas produced from organic waste coming from cattle ranches, treatment plants, landfills, etc.
According to data from California’s Air Resources Board (CARB), RNG-powered vehicles in the state removed more carbon dioxide from the atmosphere than they emitted for the first time last year. Between 2019 and 2020, the use of RNG in fleets of trucks and other vehicles grew by 25 percent. During the past five years, this shift towards RNG has risen by over 170 percent.
92 percent of all on-road fuel used in vehicles using natural gas last year was RNG. The 2020 average carbon intensity score of bio-CNG (Compressed Natural Gas form of RNG) in the mix was -5.845 gCO2e/MJ. The carbon intensity of the state’s bio-CNG continues to decline.
“This verified data means their trucks and buses leave a zero-carbon footprint while virtually eliminating criteria pollutant emissions that contribute to asthma, heart disease, and poor air quality,” Dan Gage, President of NGVAmerica, an organization promoting the use of biomethane and natural gas for transportation, said in a statement.
RNG-fueled trucks and buses that use ultra-low NOx (nitrous oxide) natural gas engines perform at levels that are 98 percent lower than the federal particulate matter PM2.5 standard and 95 percent below the NOx standard. Johannes Escudero, founder and CEO of RNG Coalition, stated that RNG addresses the problem of waste pollution as well as helps in achieving carbon neutrality.
An overlooked fuel source?
Out of 164.8 million gallons of natural gas used as motor fuel in California last year, 152.4 million gallons came from renewable sources. The use of RNG as motor fuel displaced 1.83 million tons of CO2 equivalent in 2020.
To put this into perspective, this would be like (a) lowering greenhouse gas emissions equivalent to what is emitted by a passenger car that drives for 4.6 billion miles, (b) sequestering the amount of carbon equivalent to what is captured by 2.24 million acres of American forests a year, or (c) eliminating CO2 emissions equivalent to the energy use of 220,118 homes in the state for a year.
Back in November 2020, a report at Trucking Info had cited CARB data to claim that the energy weighted carbon intensity of California’s natural gas vehicle fuel portfolio in the Low Carbon Fuel Standard (LCFS) program was below zero.
Todd Campbell, chair of the California Natural Gas Vehicle Partnership (CNGVP) and vice president of public policy and regulatory affairs at Clean Energy, said to the media outlet that the milestone of negative carbon emissions was “extremely significant” since a “growing volume” of heavy-duty natural gas vehicles were already running on California roads.
“When combined with the fact that most natural gas vehicles recently placed into service are powered by near-zero emission engines, the natural gas vehicle industry is providing the most substantial and cost-effective contributions towards California’s goals to reduce criteria and greenhouse gas emissions while eliminating the use of diesel in favor of renewable, low carbon fuels,” Campbell stated.
Switching to RNG
Among the many companies shifting their fleets to RNG is SoCalGas, the primary provider of natural gas to Southern California. In April, the company announced plans to convert 200 Ford F-250 service pickup trucks to run on renewable natural gas. The new fleet is predicted to remove more than 2,000 metric tons of CO2 equivalent annually. This is the same as removing 1,800 passenger cars from roads for a year.
“In order to achieve our sustainability goals, we work to build strong relationships with innovative partners to help us continue delivering technologies to further decarbonize the transportation sector,” Sandra Hrna, vice president of supply chain and operations support at SoCalGas, said in a statement.
By 2030, the company aims to replace 20 percent of its traditional natural gas supply with RNG. As part of this transformation, SoCalGas worked with fleet owner Total Transportation Services Inc. (TTSI) to replace its 40 diesel trucks with natural gas ones.
“In our experience, near-zero emissions natural gas trucks are the closest direct replacement for diesel trucks in terms of their power and speed, the 600-mile range they provide between refueling, the ability to fast-fuel in about 10 or 15 minutes, and most importantly, their ability to compete on a cost-per-mile basis,” Vic LaRosa, CEO and President of TTSI said to Diesel Progress.