Sustainable aviation fuel, or SAF, is key to aviation’s lower carbon future. But achieving that future will require new pathways, methodologies, approaches — and partnerships. We sat down with Todd Becker, president and chief executive officer of biorefining company Green Plains, to learn more about a new cross-industry joint venture that aims to develop one such pathway.
United Airlines, energy infrastructure specialists Tallgrass and biorefiner technologists Green Plains are working together in a new joint venture partnership — Blue Blade Energy — to use technology developed by the US Department of Energy’s Pacific Northwest National Laboratory (PNNL) to convert ethanol into SAF via an alcohol-to-jet fuel (ATJ) process.
“Blue Blade Energy is a first-of-its-kind collaboration in the SAF industry, combining partners with direct ownership to the infrastructure, pipelines, and feedstock supply necessary for success, backed by demand from one of the largest airlines in the world,” Becker tells us. “This joint venture revolves around PNNL’s innovative technology, which is completely unique in the ATJ space, converting ethanol to SAF via ketone intermediates. The new catalyst converts ethanol to a carbon-oxygen molecule bond, easier to break for conversion than the carbon-carbon bonds used in many existing ATJ technologies. This jump over the traditional olefin step results in a single-step conversion, eliminating one operational unit.”
The catalyst is also particularly robust, tolerant to impurities in water and other oxygenates, requires less energy intensity throughout the process, and is thus overall lower in production carbon impact.
“We believe the PNNL technology can be a game changer in efficiently converting low-carbon alcohol to sustainable aviation fuel,” Becker says.
In total, the partnership hopes to produce more than 135 million gallons (614 million litres) of SAF annually, United’s largest single source to date. For contrast, United today uses 10 million gallons of SAF.
Also on the agenda is the carbon accounting and verification of the end result. “Tracking carbon intensity from the corn kernel to the jet fuel tank is incredibly important to the joint venture,” Becker notes. “We are currently exploring options to determine the best solution for tracking and certification.”
Why ethanol as a feedstock?
Ethanol is an established plant-to-fuel feedstock, with standard automobile petrol/gasoline already containing up to 10 percent ethanol (marked as E10) as standard.
“Ethanol is an inherently renewable, sustainable fuel made from American-grown corn,” Becker explains. “It is traditionally used for surface transportation, blended with gasoline to reduce greenhouse gases, by about 46 percent, and particulate matter emitted from the tailpipe. But alcohol-to-jet technologies offer ethanol a crucial role in aviation decarbonisation as well.”
Indeed, the scale that corn-to-fuel ethanol has already achieved is one of the reasons that it is particularly suitable to achieving the required volumes for aviation. The US alone has over 17 billion gallons of annual ethanol production capacity.
“Low-carbon ethanol through an alcohol-to-jet technology is the most promising and effective path to large-scale SAF to help aviation reduce its scope 1 and 2 emissions,” Becker argues. “ATJ will be key to realizing success in SAF at scale, as suitable vegetable and waste oils are not produced in the enormous volumes needed to supply the demand of jet fuel that will be required to make a meaningful impact.”
A key objective for new SAF pathways is to ensure that feedstock production does not use resources that could otherwise be used for food crops.
“The corn used in ethanol production is field corn, not the sweet corn we enjoy on the cob,” Becker explains. “In fact, only 10 percent of corn grown in the US is processed for direct human consumption. And, contrary to belief, acreage for all US corn production has remained relatively steady, even slowly declining, in recent decades, while new techniques and seed varieties have in fact resulted in increased yields on existing acres.”
The corn processed as part of the biorefining to ethanol is not entirely removed from the food chain, however. Approximately a third of each kernel can be used to feed fish, poultry, cattle and other farmed animals after the Blue Blaze processing.
“Green Plains has invested in innovative technology that can produce an extremely high quality, high protein, optimal yeast content ingredient. Our corn fermented protein ensures we continue to use our existing feedstock to its fullest potential,” Becker says.
The Blue Blade partnership model is itself notable
United is participating in Blue Blade via its United Ventures arm. Like many airlines, it foresees a substantial need and is, through this and other moves, trying to signal to the market its commitment to SAF as a future fuel source.
Airline involvement is particularly welcome, Green Plains’ Becker enthuses. “Original partners Tallgrass and Green Plains didn’t want just an offtake agreement to purchase the fuel produced with PNNL’s technology — we wanted a partner to be involved in producing the fuel. We believe this is the best model. Each of us brings expertise in our respective sectors, and a founding interest in the success of the project.”
Those areas of expertise mean that Tallgrass will be in charge of the technology around research and development, building the pilot production plant, and the later construction of the full-scale SAF production facility. Green Plains, meanwhile, will provide the low-carbon ethanol feedstock and operate the facility once into the full production phase, leveraging its expertise within the ethanol industry. United’s involvement includes purchase commitments for up to 2.7 billion gallons of SAF (which works out to some 20 years of production at 135 million gallons per year), as well as involvement with development, certification and into-wing logistics.
“Each partner’s role is clearly defined along our respective areas of expertise, complementing each other’s strengths,” Becker explains. “We truly believe we have the best team assembled for the optimal chances of success from PNNL’s tech, as well as the joint venture.”
The construction of the pilot production plant is planned for 2024, while the commercial facility could begin production as early as 2028.
Author: John Walton
Published 27 July 2023
Image: Courtesy 0f United – UA SAF Truck and Plane
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