Most of the ethanol made in the US today is blended with gasoline for use in cars. ADM, one of the largest ethanol producers, plans to divert half its supply to be made into jet fuel instead.
ADM and the biobased chemical maker Gevo have signed a letter of intent that calls for Gevo to take 3.4 billion L per year of ADM’s corn ethanol output and convert it into 1.9 billion L of sustainable aviation fuel (SAF) and other hydrocarbons starting in 2025. ADM makes the ethanol at three plants in the Midwest.
CEO Juan Luciano said in an investor call that ADM is reducing its exposure to ethanol for blending with gasoline because of volatility in that market. ADM is also selling an ethanol plant in Peoria, Illinois, to Houston-based BioUrja Group.
The core of Gevo’s process is a set of methods to convert ethanol to ethylene. From there, CEO Pat Gruber explains, Gevo dimerizes, oligomerizes, and hydrogenates the ethylene to C8–C12 hydrocarbons, which it then separates into kerosene-type jet fuel, octane, and other valuable hydrocarbons.
Gevo has a related process for making jet fuel from isobutyl alcohol, including yeast engineered to produce the four-carbon alcohol from sugar and starch. The two firms are looking to deploy that technology at a new facility at ADM’s site in Decatur, Illinois, which is already equipped with carbon-capture and sequestration equipment.
Gevo’s isobutyl alcohol–based jet fuel process is certified in the European Union as emitting 75% less greenhouse gases than petroleum-based fuel manufacture. Gruber says renewable electricity, carbon capture, and control over biomass sourcing and plant design can result in a biofuel process that removes CO2 from the air over its full life cycle, a central motivation for Gevo’s collaboration with ADM. “Who cares unless we decarbonize?” Gruber asks. “It doesn’t count unless we decarbonize.”
Researchers at Harvard University, the Massachusetts Institute of Technology, and the US Departments of Energy and Agriculture recently estimated that corn-based fuel ethanol has half the carbon footprint of gasoline (Environ. Res. Lett. 2021, DOI: 10.1088/1748-9326/abde08; Biofuels, Bioprod. Biorefin. 2021, DOI: 10.1002/bbb.2225). Ken Colombini, communications director at the Renewable Fuels Association, says the members of his trade group are targeting net-zero carbon emissions by 2050.
“As the lifecycle carbon footprint of ethanol continues to shrink and the economics of ethanol-to-jet fuel processes continue to improve, we expect to see more ethanol producers exploring opportunities in the SAF marketplace,” says Geoff Cooper, president and CEO of the Renewable Fuels Association. The group’s members would also be open to switching to isobutyl alcohol, he adds.
Gruber says the ADM projects will combine Gevo’s internally developed technology with engineering packages, catalysts, and equipment licensed recently from Axens North America, an established player in olefin conversion processes. That relationship is exciting, he says, because ethylene and isobutylene are feedstocks for a huge range of polymers and specialty chemicals.
“We know the technologies work” for biobased chemicals, Gruber says. “Finally, the marketplace is becoming ripe so we can commercialize them; that’s what’s changed.”
This story was updated Oct. 28, 2021 to correct the attribution of the Renewable Fuels Association’s quote and its statement about isobutyl alcohol. They were from Geoff Cooper, RFA's president and CEO, not Communications Director Ken Colombini.