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The Inflation Reduction Act has brought sustainable aviation fuels (SAFs) into the spotlight. Aviation accounts for over 2% of global greenhouse gas emissions, and there is a lot of R&D geared toward finding ways to reduce the airline industry’s carbon footprint.
Bio.News spoke with experts at Gevo, a renewable chemicals and advanced biofuels company, to understand their ethanol-to-olefins (ETO) technology and how it aims to make aviation more sustainable.
The following has been edited for length and clarity.
Bio.News: When was ETO technology developed?
Gevo has been working on converting ethanol into olefins since roughly 2015. The first-generation technology targeted specific olefins such as propylene or isobutylene but suffered from poor yields. Gevo began development on the current generation of ETO in 2019, focusing on combining ethanol dehydration and olefin oligomerization (or growth) processes into a single step, which could bypass the selectivity challenges posed in the earlier generation technology.
Bio.News: What are the commercial uses of ETO technology?
There are multiple commercial uses of ETO. We are working on one with LG that is the direct production of propylene from ethanol in a single step. ETO can also be used to produce a mixture of olefins like what is produced in the steam cracking of naphtha, the process used to produce the vast majority of crude oil-derived olefins today. In this way, Gevo’s technology can help chemical producers consider ethanol as a renewable, low-carbon, direct replacement for naphtha derived from crude oil.
However, the most important commercial use of ETO for Gevo is that our ETO process allows us to install more capacity to produce jet fuel at a lower capital cost and energy use. The ETO process is significantly more capital and energy efficient than dehydration of ethanol to ethylene, the first step in existing processes to produce jet fuel from ethanol. We believe that once ETO has been commercialized, its lower costs will enable Gevo to build more ethanol-to-jet capacity from the same amount of capital, and its lower energy use will make the process easier, i.e. cheaper, to decarbonize.
Bio.News: What role does ETO play in SAFs?
Existing, commercial-scale technologies to convert ethanol into SAFs rely on dehydration of ethanol to ethylene, which is generally the most expensive and energy-intensive portion of the process, and then convert that ethylene into higher carbon number olefins needed for fuels in separate steps. By combining ethanol dehydration with formation of higher olefins, we have drastically reduced the amount of energy it takes to produce aviation fuel from ethanol and reduced the downstream reaction steps, all of which saves capital.
Bio.News: Gevo has claimed to use low-carbon corn for its ethanol. What makes it low carbon?
Gevo’s low-carbon approach involves using sustainable farming practices, such as cover crops and reduced tillage, to reduce carbon emissions associated with corn cultivation. The company will also source corn from farmers who utilize regenerative agriculture techniques to improve soil health, increase carbon sequestration, and reduce greenhouse gas emissions.
SAFs may be a game-changer in aviation. Both Boeing and Airbus have pledged to make their fleets capable of handling SAFs by the end of the decade. However, Boeing’s CEO recently announced that SAFs will never have cost parity with conventional aviation fuels. Still, there is a concerted effort by the government and private sector to scale climate-friendlier transportation methods.
