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Something is brewing — literally, with yeast — in the agricultural lands of rural America, from Luverne, Minn., to Lake Preston, S.D., to northwestern Iowa. Hundreds of thousands of gallons of carbon-neutral gasoline, jet fuel and diesel are being produced on a scale that could be worth billions of dollars.

These sustainable fuel sources aren’t some pie-in-the-sky fantasy. They’re drop-in ready for internal combustion engines and the existing infrastructure that powers them, from gas station pumps to commercial airliners to boats, all the while reducing air pollution. Best of all, these biofuels emit zero particulates, sulfur and nitrogen, thereby reducing air pollution and greenhouse gases.

“We are on a crusade to solve the greenhouse gas and transportation problem,” says Patrick Gruber, CEO of Englewood, Colo.-based Gevo. “We know we can solve it.” The company is a leading U.S. producer of energy-dense liquid hydrocarbons and renewable chemicals.

Gruber, who holds a Ph.D. in chemistry from the University of Minnesota, invented the compostable plastic cup with green bands that’s used in cafés. He cofounded Gevo in 2007 to produce biofuels with patented yeast strains and organic matter, namely corn.

CEO Patrick Gruber

CEO Patrick Gruber

Gruber says that while the growing use of electrification and testing of hydrogen fuel cells might make biofuels obsolete, it’s also true that measuring only exhaust emissions is a false, inaccurate representation of overall environmental impact. Electric vehicles and boats don’t produce emissions directly, but they still rely on electricity from the grid, which in the United States gets 60 percent of its power from fossil-fuel sources, according to the U.S. Energy Information Administration.

The basic premise of Gevo’s biofuels is that they start with corn. The corn is sourced as a carbohydrate, meaning carbon bonded to hydrogen. Then the corn and yeast are brewed to create simple alcohols related to the desired fuel, such as isobutanol (a building-block compound of Gevo’s aviation fuel). This fermentation process connects hydrocarbons by adding more hydrogen.

Once these alcohols are created, a chemical process strips the remaining oxygen, then puts the necessary amount of chain links together to create the desired fuel. Gasoline has a carbon chain length of eight; jet fuel, 12; and diesel, 18. “Conceptually, it’s incredibly simple,” Gruber says. “Learning how to do it in a practical sense took a lot of effort.”


The main challenges preventing boaters from filling up with renewable gasoline or diesel are market forces and public policy, including subsidies for the fossil-fuel industry that keep traditional fuels cheaper. However, in states such as Washington, Oregon and California, which have green tax credits or emissions penalties, Gevo is competitive.

“The marine industry is also segregated,” Gruber says. Until now, most of Gevo’s existing track record has been with the aviation industry, in part because it’s centralized. But as regulators begin to hold boaters accountable for carbon emissions, he says, there will need to be incentives to switch to renewable fuel sources. It’s also safe to imagine that alternative energy sources, such as electric and hydrogen power, are likely to enter the aviation market last, due to the myriad demands of flight (longer distances, higher speeds, etc.) on batteries. In the shorter term, real financial penalties for carbon pollution, like in the European Union, incentivize airlines to make the switch to more eco-friendly fuels.

Gevo’s plant in Luverne, Minn., produces isobutanol and ethanol.

Gevo’s plant in Luverne, Minn., produces isobutanol and ethanol.

“For boats, they are going to get held accountable for their carbon emissions. That’s in the tea leaves. It’s coming,” Gruber says. “Carbon benefits need to be available for boats.”

“This is about trying to get CO2 emissions down, leveraging what exists and getting it done sooner rather than later,” he says, adding that he sees large center consoles as an opportunity in the boating sector. “When you see the market demand for how boats are being powered, they are going to these outboard motors. Good. I want to optimize a fuel for [them]. I’ll bet you we can get those running better and going farther per tank of gas. I bet we can get some fuel efficiency increases.”

He pauses, then adds: “We’re working on that.” 

This article was originally published in the June 2022 issue.



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