Utilizing fermentation CO2 to produce next generation coproducts
The opportunity in carbon capture utilization and sequestration has fired the imagination of the ethanol industry. While multi-state pipeline projects involving sequestration have run into roadblocks as of late, utilization developers are hoping to gain momentum and transform wasted CO2 into a new coproduct.
Converting corn to ethanol generates significant amounts of pure carbon dioxide during fermentation. A 100 MMgy plant emits roughly 1,000 tons per day. Collectively, that’s 45 million tons of CO2 produced each year by U.S. ethanol plants.
Currently, about 10% of this is already utilized by the merchant market, primarily for food and beverage use, supplying about 40% of the estimated 9 million tons U.S. demand annually. The world’s merchant market for CO2 tops 22 million tons. Not only is there more ethanol CO2 supply than market demand, but food and industrial use generally doesn’t reduce an ethanol plant’s carbon intensity score, as the CO2 ultimately gets released to the atmosphere.
Sequestering CO2 is one route to reducing ethanol’s CI, but only a few ethanol plants are located above geologic formations suitable for sequestration, and the big pipeline projects to connect facilities to sequestration sites have run into roadblocks. Enhanced oil recovery (EOR) is another route, but again, require pipelines or proximity to oilfields. Just two Kansas plants capture their CO2 for EOR, Bonanza BioEnergy and Arkalon Energy, which gets pipelined 15 and 90 miles away, respectively. Looking at the current pathways approved by the California Air Resources Board for the California low carbon fuel standard (LCFS) indicates that neither plant has EOR factored into their CI scores.
Given the limitations for sequestration for many producers, utilization may just be the route that a big portion of industry has to consider to lower ethanol’s CI and, potentially, turn it into new coproducts such as chemicals and other fuels. Ethanol Today spoke to four developers of CO2 utilization projects.
LanzaTech
LanzaTech focuses its work on transforming carbon waste into fuels and chemicals. The company commercialized its technology in China, feeding bacteria off-gasses from a steel plant to produce ethanol. Since then, it has developed fermentation processes to convert carbon-rich gases to other chemicals, such as acetic acid, isopropanol, acetone, butanol, succinct acid and isoprene, as well as protein for animal feed.
LanzaTech has several projects focused on utilizing industrial waste gases, primarily in Europe and China. In the U.S., the company recently announced a project with Technip Energies USA to produce ethylene from CO2 that garnered $200 million in DOE funding. LanzaTech’s fermentation technology using CO2 and green hydrogen will first produce ethanol, followed by Technip Energies’ Hummingbird process to convert ethanol into ethylene.
“Ethylene is a key building block for thousands of chemicals and materials and is often referred to as the world’s most important chemical,” a LanzaTech spokesman explains in a reply to emailed questions. “The project will be the first in a portfolio of projects to capture CO2 emissions from steam crackers into sustainable ethylene.” While corn ethanol fermentation would provide a pure CO2 stream, the LanzaTech fermentation technology requires hydrogen. “Until green hydrogen is readily available at commercial scale, the use of a pure CO2 stream as feedstock for recycled carbon ethanol may be limited,” the spokesman explains.
Other projects in development are targeting renewable electricity for electrolysis to provide the hydrogen for catalytic conversion of CO2 to E-fuels, looking at the growing demand for renewable natural gas and the expected demand for green methanol as the maritime industry decarbonizes.
CapCO2 Solutions
“Methanex is the largest methanol broker in the world, and when I talked to them and described what’s possible at ethanol plants, they’re like: ‘They’re sitting on a gold mine,’” explains Jeff Bonar, CEO of CapCO2. “The CO2 is pure, with very large quantities and in a place that already has good logistics for creating new fuels and moving them to places.” The price of conventional methanol, he says, has been averaging $500 per ton, though it currently commands closer to $900 per ton.
One driver for a transition to green methanol is the maritime industry. Bonar points to Maersk. “The best known and largest container company has made a heavy commitment to green methanol. They have four ships on the water now and will have something in the 20s by 2030. Right now, the world only makes 13% of the green methanol needed to run the ships they’re planning on operating on green methanol by 2030.” A European company, Maersk is partly responding to EU policies, but Bonar adds, “A lot of consumer brands want to be able to say we have zero carbon tennis shoes or whatever. They need to ship things on green methanol ships, and they’re committed to using the space.”
One attraction of methanol is that any engine currently running on diesel can utilize methanol with minor modifications, Bonar explains. Other alternative fuels in consideration like hydrogen or ammonia require major engine upgrades, plus massive modifications to infrastructure, unlike methanol which can be transported and stored within existing systems.
CapCO2 is targeting a cost of $560 per ton for green methanol, Bonar says, utilizing a European technology developed by Methylennium Energy. CapCO2 recently pivoted from its first announced pilot project to another located in Minnesota, which it expects to announce shortly and be operational by the end of the year. The modular unit fits in a shipping container. “The average sized ethanol plant will need 10 to 15 to process all of their CO2,” he says.
A prerequisite for green methanol production is renewable electricity, Bonar adds, used to generate the hydrogen needed in the conversion process. CapCO2’s system is attractive to renewable electricity providers, he says, because it can be turned on and off in a matter of 10-15 minutes, unlike conventional methanol equipment that has to run 24/7. “They love the idea of someone who will buy the electricity when other people don’t want it.”
Storm Fischer’s Vision
Storm Fischer Hydrogen is taking a different development approach—tapping into off-the-shelf technologies at a much larger scale to convert all of the CO2 from an 80-100 MMgy plant.
“We’re a clean hydrogen and E-fuels development company,” CEO Judson Whiteside says. The hydrogen itself may be a viable product in the future and will be needed for sustainable aviation fuel and green ammonia. But to start with, Storm Fischer is focused on E-methane and E-methanol, building on its experience in biogas.
Storm Fischer has over 15 years of experience in developing and operating biogas-based renewable natural gas (RNG) facilities. Seeing a growing demand for green methane, the company sold its biogas assets, which included North America’s largest food-waste biogas plant in London, Ontario, and turned its focus to hydrogen and E-fuels. E-methane is a source of renewable natural gas, which fits in existing infrastructure and now has a well-established market.
The market for green methanol, on the other hand, is relatively new, though conventional methanol, mostly derived from natural gas, is one of the top five base chemicals. Methanol also fits in existing infrastructure, generally transported by rail with existing storage and port facilities.
Storm Fischer plans to use off-the-shelf technologies. “We crack the water, make hydrogen and pair that with biogenic CO2 sources,” Whiteside says, “and we make either E-methane or an E-methanol product through a catalytic conversion process.”
“Our preferred choice for biogenic CO2 sources is ethanol facilities,” Whiteside says. The volumes line up with the size of their planned projects, producing roughly 120,000 tons of methanol annually from an 80-100 MMgy ethanol plant. Plus, many ethanol facilities are located in good renewable power markets, particularly wind markets in the plains’ states from Texas to the Dakotas. The scale of Storm Fischer’s facilities calls for a significant power load around 200 megawatts, Whiteside explains. “It fits really well in terms of the wind project sizes that we’re seeing, between 100 to 300 megawatts.”
“We can procure power from existing sources,” he says, “but we really like new sources that are being proposed. Some of those projects are challenged in the early stages economically because of the current power markets, whereas we come in and we bring a load that can benefit their economics.” He also expects to layer on solar projects because they typically are easier and faster to develop than large wind projects.
Storm Fischer is close to lining up the three key elements for its first commercial project — the ethanol producer supplying the CO2, the renewable power supplier and the off-take agreements—after which the detailed engineering needed to finalize financing will begin. The targeted completion date for that first project is 2028.
RCT-Lena
Adkins Energy’s project sheds light on other dimensions of developing a new fuel from its fermentation CO2. In Lena, Illinois, Adkins expects to have its demonstration plant operating by late fall, says COO Bill Howell. Adkins Energy has formed a joint venture with RCT-US called RCT Lena, utilizing Polish technology from Real Carbon Tech to produce methanol or DME (dimethyl ether useable in diesel engines).
“Our goal is to lower the carbon intensity score on the ethanol that we’ve been making for 20-plus years, so it becomes a viable feedstock for other clean chemicals. And to diversify our product line,” Howell says. He recently stepped back as CEO of Adkins Energy to focus on the new project and become CEO of RCT-US.
The modular unit planned for Adkins’s demonstration project is sized at 800 to 1,000 tons/year. “It’s a small unit,” Howell says. “A 200 ton-per-year unit was the pilot done in Warsaw, Poland, so this is the next step up.”
Other necessary steps are underway, he says. “We are currently having the process analyzed to see what the drop in CI would be for the ethanol and also get clarification on the 45Q model and pathway created so the DOE can give us the approval.” Initial indications are it will qualify for 45Q and will result in a CI reduction between 25 and 30 points. “We’re still waiting for that data to be finalized, and at the same time we have a second company that will do the review and validation which will set us up to go to the DOE for approval.” With Adkins’ CI currently scoring a little over 50 points, the project will put Adkin’s ethanol in good range for becoming a sustainable aviation fuel feedstock, Howell says.
One of Howell’s challenges has been sourcing renewable power. “We have all these data centers coming online that require tremendous amounts of electricity putting stress on the grid system,” he says. “Getting enough electricity is going to be a challenge, so we’re looking at all kinds of possibilities.” Adkins already has combined heat and power and claims 100% nuclear power. But while nuclear power is considered zero emission, it’s not considered a qualifying source for E-fuels in Europe—a target market for E-fuels. “At some point I think they’ll end up switching that,” he says. “Today we are focused on solar, wind or hydro.” Illinois, he explains, allows users to identify which power source they want to use, so as long as a utility sources one of the renewables and the renewable electricity, credits are available to claim. “The issue is how much do you want to pay,” Howell says, “and availability.”
Howell considers CO2 utilization a great opportunity for the ethanol industry. “We need to change our mindset from thinking about CO2 as a waste product and start recognizing the value this material has. We just have to get innovative enough to figure out how to use it properly,” he says. Producers also need to recognize where they are in the organizational life cycle—one he learned about in studying about a totally different sector, but could see applies to businesses. “Companies start out growing the business, reach a satisfying level, and then they begin to decline. Years later, they’re no longer there. What we’re trying to do is identify the right technology, create a new future and start the growth process all over again.”