Verbio Grand Opening

Germany’s Verbio has unveiled its first North American biorefinery in Iowa. After completion of its second phase of construction next year, it will produce both RNG and ethanol. The biogas is cellulosic, the alcohol will be corn derived.
By Katie Schroeder | July 19, 2022

Towering over the skyline outside Nevada, Iowa, the sprawling Verbio biorefinery is an impressive anomaly, not by its appearance but its capability. In early May, a grand opening was held for the first-of-its-kind renewable natural gas plant, the only industrial-scale RNG operation in the U.S. using corn stover as a feedstock. “This marks the formal launch of our company as an emerging leader in the renewable energy field, [and specifically] in the production of renewable natural gas,” Greg Northrup, president of Verbio North America Holding Co., told the government officials, community members and corporate representatives on site for the startup celebration and plant tour. “This is the third leg of the stool in renewable fuels for Iowa. You’ve been doing ethanol for years; you’ve been doing biodiesel. Now, we add to this piece of the equation, renewable natural gas.”

Earlier this year, the plant started producing stover-derived RNG at what it calls the “ethanol-gallons-equivalence” rate of 7 MMgy. When the second phase of its plan is complete early next year, the biorefinery will be producing RNG at the equivalence of 19 MMgy while, notably, also producing 60 MMgy of ethanol—actual ethanol—from corn itself. The ethanol and RNG processes will be integrated; thin stillage from the ethanol process will be used as a supplementary feedstock for RNG alongside corn stover. “Integration of the ethanol production process with the renewable natural gas process will result in higher efficiencies and improved sustainability,” Verbio’s founder and CEO, Klaus Sauter, said at the grand opening. “No one has a higher output of renewable sustainable energy per metric ton of biomass than Verbio.” The company currently has 10 locations across Asia, Europe and now, North America. Sauter explained that the integration of these processes allows Verbio to achieve lower emissions, giving them opportunities in low-carbon markets. The company also plans to produce corn oil, nitrogen fertilizer and, eventually, synthetic natural gas from CO2.

The RNG Process
“Sometimes I’m asked, when did we start injecting renewable natural gas?” said Greg Faith, general manager of Verbio Nevada. “It was Saturday, November 6, at 9:43 in the morning. I was standing out there with the Alliant guys as they were valving us in, and I texted … and I said, ‘We did it.’” As the biorefinery produces RNG from corn stover while making progress on the ethanol plant and preparing its systems to incorporate thin stillage, it continues to enhance its feedstock supply network. 

 Eric Phipps, agronomy and operations manager at Verbio, explained that Verbio acquires its stover within a 45-mile radius of the plant. Phipps’ department contracts the acres, chops and bales the stover, and transports it to the biorefinery. He explained that they also deal with humus management.  “Basically, the farmer gets paid for the bale, we’re responsible for all the other expenses,” Phipps said. “We do all the trucking, we do all the baling, we do all that kind of stuff. So, once the contracts are in, it’s kind of a one-stop shop, the grower is off the hook on any of that.” Verbio plans to bale at least 40,000 acres of corn stover this year, while using some bales left over in storage from the facility’s previous purpose.

Production manager Aaron Chadwick said that once the bales are put in storage, the material handler will come and check the moisture percentage of the bale. “Once he checks the moisture, it will determine which line it’s on,” Chadwick explained. “We have two lines, we have a south line, which is our line one, and a north line, which is our line two. Our south line will run our lower moisture bales, 25% and under, while our north line will run 25% up to 45%.”

The corn stover is then loaded onto the conveyer belt and sent through the hammer mill to break up the large pieces, which is then filtered through a screen. The hammer mill was a source of plugging early on, but these issues have been worked through. “At this point, we add water to it, mix it up and send it out to our digesters for food,” Chadwick said. “Right now, we’re running about five tons an hour, we want to get to 10 tons an hour in the future.” The particles then spend 25 days in the fermentation tanks, switching between tanks every half hour.

Corn ethanol wet cake, when used for RNG, will be treated as its own process stream, going to separate fermentation tanks than the crop residue RNG. “Ultimately, we’ll take that thin stillage, and we’ll concentrate it up into a syrup product and that’ll get mixed into our wet cake [and fed] into our digesters,” Verbio chemical engineer Blake Logan explained. The fermentation tanks have 10,000 cubic meters capacity with space for 3,000 cubic meters of gas at the top. “The pressure from fermentation as it’s producing will actually push it to the header and then ultimately to gas refining,” Logan said. Any unfermentable material in the tanks will float to the top and be removed and sent to solids separation. He explained that this material becomes digestate which has a variety of uses including biofertilizers and bioplastics. Sauter explained that the digestate—also known as humus—will be “principally returned” to farmers and used as a fertilizer.

When the biogas comes off the fermentation tanks, it is made up of 50 to 60 percent biomethane, 40 to 50 percent CO2 and some moisture and other impurities, according to a Verbio engineer onsite. The plant then cleans the CO2 until it is 99 percent methane, the same purity as natural gas derived from fossil fuels. After the majority of the CO2 is removed, the biomethane is run through an activated carbon filter and zeolite mole seize beds. Verbio then uses an online gas analyzer to measure the product’s purity and make sure the gas meets specs before it is compressed to grid pressure using a screw compressor. The gas is analyzed again before it is injected into Alliant Energy’s grid. The RNG is then used both regionally and throughout the country. Some RNG will also be used onsite as Verbio plans to utilize the low-carbon fuel to power clean-burning CNG vehicles at the complex, according to Sauter.

 “I’m proud of the teamwork between Verbio and the many employees at Alliant Energy to develop standards and regulations for renewable natural gas, as well as construct interconnection options for this site,” said Terry Kouba, senior vice president of Alliant Energy. “We’re finding new ways to provide reliable, renewable natural gas service for our natural gas customers.”

Lawmaker Support
Government officials at the local, state and federal level were present to offer their support and congratulations for Verbio’s accomplishment. “I couldn’t be more grateful to Verbio for choosing to invest in our state. And I can promise, without hesitation, that you will not be disappointed that you did,” Iowa Gov. Kim Reynolds said at the event. She outlined the importance of biofuels to Iowa’s economy, explaining that renewable fuel makes up $4 billion of the state’s annual GDP. She also referenced the technology used to make RNG at Verbio. “It’s a remarkable testament to the countless uses of corn and how many more are just waiting to be discovered and unleashed,” Reynolds said.

Senator Chuck Grassley planned to visit the grand opening but had to stay in Washington D.C. due to scheduling conflicts. He sent a video with his comments and congratulations. “As many of you know, this is the first of its kind plant in the United States and will surely benefit Iowa farmers. It will provide good paying jobs in central Iowa,” Grassley said.

Other government officials in attendance included U.S. Reps. Randy Feenstra and Marionette Miller-Meeks, as well as Brett Barker, mayor of Nevada. Miller-Meeks highlighted Iowa’s reliance on renewable energy, noting that the state produces 50 percent of its energy from renewable sources. Feenstra praised the cooperation between the government, private industry and local stakeholders, and said that Verbio’s refinery should serve as a “blueprint” for plants across the state. A member of the German Parliament, Oliver Grundmann, was also in attendance to support the Germany-based Verbio.

Moving Forward
In the future, Verbio hopes to build more plants throughout the U.S. as well as expand its coproducts at the Nevada biorefinery. One of the things the company hopes to make in the future is synthetic renewable natural gas. “With renewable hydrogen, produced from electricity coming from wind and solar farms in Iowa, Verbio will produce synthetic natural gas and hopefully in near future, synthetic chemicals with another big German chemical company,” Sauter said. “It’s the next challenge on our trip for a decarbonized and a sustainable global economy.”

In closing, Sauter expressed his excitement about being a part of the U.S. biofuels market and commitment to growth. “I am very excited about the future here and knowing that what we are doing is a win-win-win-win, for farmers, rural communities, the environment, sustainable renewable energy, our partners and, finally, the shareholders.”

Verbio represents a unique example of how the versatile corn plant can be as a feedstock for multiple renewable fuels. Sauter mentioned that Verbio is “examining potential cooperation arrangements with other ethanol manufacturers in order to increase the production capacity of renewable natural gas in the United States.” If successful, Verbio’s forthcoming integration of ethanol production with stover-based RNG may be one of the fullest extractions of value from corn, kernel to stalk, achieved to date.

Author: Katie Schroeder
Contact: [email protected]