Aemetis Inc., a renewable natural gas (RNG) and renewable fuels company, has received certification from the California Air Resources Board (CARB) for a new LCFS Tier 2 fuel pathway for the Aemetis Advanced Fuels Keyes ethanol production plant utilizing renewable dairy biogas as a process energy input.
The new pathway reduces the carbon intensity (CI) of Aemetis’ fuel ethanol from 67.3 to 65.6 – utilizing dairy biogas from two dairies with an average CI score of -426. Aemetis began operating two anaerobic dairy digesters and a four-mile private pipeline in September 2020 near the company’s ethanol biorefinery in Keyes, Calif. The new ethanol pathway certification from CARB is effective as of Oct. 1, 2020.
The Aemetis Central Dairy Digester Project is a collection of dairy lagoon anaerobic digesters that are built, owned and operated by Aemetis Biogas LLC utilizing waste animal manure to generate renewable methane gas to produce negative CI RNG for transportation use to displace diesel fuel. An estimated 25% of methane emissions in California are produced by dairy waste lagoons.
Once complete, the Aemetis Central Dairy Digester Project is expected to include over 30 dairy digesters in the current phase (with plans to expand to more than 52 dairies), and utilize 36 miles of private pipeline owned by Aemetis, a centralized gas clean up unit located at the Aemetis Keyes ethanol biorefinery, an RNG onsite fueling station and an interconnection to PG&E’s natural gas pipeline.
“This is another significant step in our multi-year plan to decarbonize the Keyes ethanol production facility,” says Eric McAfee, chairman and CEO of Aemetis Inc. “This CARB approval is our first utilization of negative CI dairy biogas to produce transportation fuel. The Aemetis Keyes biorefinery is expected to serve as the hub for the processing and distribution of our negative CI RNG and allow us to serve multiple markets with low or below zero CI liquid and gas renewable fuels.”
The company plans to begin construction of the next five dairy digesters and the additional 32 miles of biogas pipeline in the second quarter, with five more dairy digesters set to begin construction in the third quarter and five digesters beginning in the first quarter of 2022 for a planned total of 17 dairy digesters and a 35-mile biogas pipeline.
Photo: Eric McAfee