RNG Revolution: The North American Renewable Natural Gas Industry Has Boomed over the Past Decade and Potential Remains Vast.

by Anna Simet (Biomass Magazine) ... Particularly for those feeling the heat when it comes reducing carbon footprints, interest in renewable natural gas (RNG) as an alternative vehicle fuel is an all-time high, and for good reason. Not only does it meet the most stringent emissions requirements, but for utilities and companies at which large vehicle fleets are essential for operating, making the switch is relatively easy and inexpensive. Announcements of transitions for large vehicle fleets are made almost daily—for example, in early September, the New York Metropolitan Transportation Authority inked a deal with Clean Energy Fuels Corp. to fuel the MTA’s 800 transit buses with RNG. Less than a week later, CEFC announced that, in just a 45-day period, it had made new and extended deals for the supply of more than 20 million gallons of RNG for municipal and refuse vehicle fleets and fueling stations across the country.

Coincidentally, California happens to be the heart of North America’s RNG boom, where conventional on-road natural gas is being rapidly displaced by RNG. In 2019, 77% of all on-road fuel used in natural gas vehicles in the state was RNG, according to the Coalition for Renewable Natural Gas, and its use as a transportation fuel has increased 210% in the past five years.

As for bright spots in further building out the industry, Escudero (Johannes Escudero, executive director of the RNG Coalition) says landfills still represent the largest, stationary feedstock, so it continues to be the lowest-hanging fruit from a development standpoint. “However, due to the environmental and economic incentives included in recent policies, there is an increased effort to develop RNG production facilities from livestock waste (primarily dairy manure) and wastewater treatment facilities,” he says.

The U.S. EPA’s Landfill Methane Outreach Program, which tracks projects via its Landfill and LFG Energy Project database, indicates landfill-gas-to-energy projects are operating in 48 states, roughly 75% of which generate electricity. Breaking down numbers for the U.S., there were roughly 399 operational LFG-to-electricity projects operating in August, 99 direct-use projects, 58 RNG pipeline injection and nine RNG local use, according to LMOP data.

According to the EPA AgSTAR project database, as of March 2020 there were 255 operational digester projects utilizing livestock manure in the U.S. Nearly 80 percent of these are at dairy farms, 14 percent are at hog farms, and the remaining utilize mix of animal manure, including poultry and beef cattle. Most of these projects generate electricity—roughly 84 percent—and many also recover waste heat for cogeneration. More than 20 manure-based digester projects are currently producing RNG from their biogas, with a variety of RNG end uses including electricity, vehicle fuel and pipeline gas. The RNG Coalition asserts there are 8,000 large farms and dairies are potential candidates for ag waste/manure-to-RNG production.

One of the relatively few food waste-to-RNG projects is CR&R Environmental Services’ AD project in Perris, California, which uses residential and commercial yard and food waste. Though the project has an initial maximum capacity of 83,600 tons per year, additional phases are planned to build out capacity to four times that amount. In 2018, CR&R began injecting RNG into the SoCalGas fossil natural gas system via a newly built 1.4-mile pipeline, which CR&R extracts the RNG back out of to fuel about 400 of its waste-hauling trucks. READ MORE