U.S. EPA Widens Allowable Feedstocks For SAF

 LanzaJet plant
Credit: LanzaJet

LanzaJet has received approval from the U.S. Environmental Protection Agency (EPA) to use ethanol in the production of sustainable aviation fuel (SAF) and generate credits under the Renewable Fuel Standard (RFS) program. 

This is the first approval for a so-called “biointermediate” step in renewable fuel production and unlocks the potential to use new feedstocks in the production of SAF.

LanzaJet plans to use ethanol produced from sugarcane to produce alcohol-to-jet SAF at its first plant on Soperton, Georgia. Planned to become operational in 2023, the Freedom Pines Fuels plant can produce 10 million gal. of SAF and renewable diesel per year. The EPA calculates the fuels will achieve a 54-66% greenhouse gas reduction when compared to fossil fuels.

Armed with the first-ever EPA approval for a biointermediate feedstock, LanzaJet plans to seek approvals for additional sources of ethanol, including novel waste feedstocks such as captured industrial CO2 emissions.

For the wider industry, the fact that renewable fuels made with a biointermediate step can now generate credits under RFS is a major step forward. Previously, RFS regulations required renewable fuel producers to bring all their raw feedstocks to the refinery for preprocessing where the finished fuel is produced, requiring large and expensive facilities.

The issue has not been critical for initial commercial-scale plants producing SAF from fats, oils and greases, an industry expert says, because preprocessing is relatively straightforward and there is an established supply chain and delivery networks for these bio-feedstocks, making it economically feasible to concentrate all production activity at the refinery site.

But several startups plan to use feedstocks that require significant preprocessing, where it can make sense to do the processing closer to the feedstock. Before the RFS rule change, the requirement to do all significant processing in one location was prohibitive. Allowing a step to take the biomass and prepare it before going to the refinery was necessary to unlock new feedstocks, the expert tells Aviation Daily.

In addition to LanzaJet and ethanol, examples include Fulcum BioEnergy, which will convert municipal solid waste into a biointermediate for delivery to fuel refineries. Alder Fuels plans to convert forestry and agricultural waste into a pyrolysis oil that will be upgraded into a “biocrude” than can then be refined into SAF in existing petroleum refineries.

The EPA’s biointermediate rule includes detailed tracking and reporting to ensure compliance with the RFS, the expert says, adding that the rule so far allows only one biointermediate stage as the agency is not yet comfortable extending that tracking process to more than one step.

Graham Warwick

Graham leads Aviation Week's coverage of technology, focusing on engineering and technology across the aerospace industry, with a special focus on identifying technologies of strategic importance to aviation, aerospace and defense.