Renewable natural gas (RNG)—also known as biomethane—is a model alternative fuel.
Produced from waste feedstocks, RNG delivers benefits throughout the fuel cycle. Making RNG captures greenhouse gas (GHG) emissions from agricultural waste and landfills, and NGVs that run on RNG deliver the same low-pollutant and greenhouse gas emissions they achieve when running on conventional natural gas.
RNG has the lowest carbon intensity (CI) values of all fuels rated for California’s Low Carbon Fuel Standard. According to the California Energy Commission (CEC), RNG from landfill gas and dairy digester biogas reduces life-cycle GHG emissions to 85–90 percent below those of diesel fuel, while RNG derived from high-solids anaerobic digestion can reduce life-cycle GHG emissions to roughly 115 percent below those of diesel.
We can put proven technologies to use right now to convert California’s vast waste feedstocks—from dairies, wastewater treatment plants, municipal solid waste plants, agriculture and landfills—to clean-burning RNG.
Waste Management’s fuel production facility at the Altamont Landfill in Livermore already generates as much as 13,000 gallons of RNG per day. The company expects to fuel its entire California NGV fleet with RNG in the near term.
Waste Management estimates that California’s current recoverable RNG resources could displace more than 900 million gallons of diesel fuel annually. That’s about 25 percent of the diesel fuel used for transportation in California each year.
As of March 2016, the CEC had awarded nearly $51 million in grant funding from the Alternative and Renewable Fuel and Vehicle Technology Program to support biomethane production projects.
Clean Energy is already selling RNG under the Redeem brand at the majority of its public CNG and LNG stations in California, and it’s pricing the fuel on par with conventional CNG and LNG.
For RNG to reach widespread availability, however, we need to address distribution and scale challenges. RNG can be delivered by truck, but injection into the natural gas pipeline system is essential to realizing the fuel’s full potential. In recognition of that fact, the California Public Utilities Commission has authorized $40 million in interconnection incentives for biomethane producers through 2020.
Currently, RNG production costs are relatively high due to the small scale of most non-landfill production facilities and other factors common to emerging technologies. But larger projects, competitive pricing for equipment and contractor services, and reduced costs for interconnecting with utilities should result in lower costs over time.