Verbio’s Iowa Plant Combines RNG and Ethanol Production
Verbio’s Nevada, IA biorefinery is the first in North America to combine ethanol and renewable natural gas production at an industrial scale. Aerial photo courtesy of Verbio; ground-level photos by Jerry Perkins.
Verbio is firing up ethanol production in central Iowa, making it the first industrial-scale biorefinery in North America to combine ethanol and renewable natural gas (RNG) production using corn and corn plant residue as feedstocks.
Verbio began producing RNG from corn stover at its Nevada, IA plant in December 2021 at a capacity of 7 million ethanol gallons equivalent (EGE) per year with the completion of the first phase of its project to turn the plant into a biorefinery. Phase II is now being completed with the commissioning of corn-based ethanol production, eventually at a rate of 60 million gallons of ethanol a year. An additional 19 million (EGE) of RNG will be produced from the ethanol plant’s wet stillage, according to CEO Claus Sauter, who said Verbio has spent $250 million upgrading the plant to produce ethanol.
The plant will have 100 employees once ethanol production begins. Verbio has more than 1,200 employees in the United States, Canada, Europe, and Asia and operates North American production sites in Iowa, Indiana, and Canada.
Verbio purchased the Nevada, IA plant from DuPont for an undisclosed amount in November 2018. DuPont built the plant to produce 30 million gallons a year of cellulosic biofuels made from the leaves, stalks, husks, and cobs of corn plants known as stover.
Verbio collects stover for its RNG production from farms within a 30- to 60-mile radius of the plant. The company completed its second harvest of corn stover in early November 2023, when it secured stover from 45,000 acres of farmland for producing RNG this year.
Corn for ethanol processing is also procured locally and stored in two, 500,000-bushel steel storage tanks erected by Sukup Manufacturing Co., Sheffield, IA. The company estimates it will need 20 million bushels of corn to produce 60 million gallons of ethanol annually.
Strategically Located
“One of the reasons we are in the Midwest is because corn is cheaper here than anywhere else in the world,” Sauter noted. “There is an economic logic behind using corn to make renewable biomass-based materials.”
Verbio has developed a unique technology which integrates RNG and ethanol production, Sauter told Processing Journal during an exclusive interview and tour of the Nevada plant, which incorporates advanced technology currently being used at the company’s plants in Germany. Verbio’s in-house research, development, and plant engineering teams developed its corn stover-to-RNG technology and the biorefinery concept of combined ethanol and RNG production between 2008 and 2014.
The technology enables Verbio to produce green renewable molecules from different biomass feedstocks and agricultural residues for a wide range of sustainable applications, Sauter stated. Those applications include not only biofuels and bioenergy, but also feed, food, agricultural, and chemical products. Processing includes using raw materials in multiple ways by recycling processes that leave little waste. Carbon dioxide emissions are reduced by as much as 90% for RNG, compared with products from fossil sources.
Producing products with lower carbon intensity (CI) provides Verbio with an advantage in the marketplace because its ethanol can command a premium price. “We have a much lower CI score than traditional ethanol plants because we produce more ethanol with 50% less natural gas, and we get more energy from each bushel of corn,” Sauter noted.
In addition to RNG and ethanol, the Verbio process yields humus – a soil amendment – and organic fertilizers, which the company sells to local farmers through its Verbio CropCare sustainable fertilizer product line. The company is looking at more widely marketing its Verbio CropCare products through multiple options including, but not limited to, working with existing distributors and applicators. Corn oil extracted from the ethanol process will also be sold.
Company Origins
Verbio is based in Zörbig, Germany, but the company’s main focus is now on the U.S. renewable fuels market, so Sauter is spending more of his time on this side of the Atlantic. “I am a farmer’s son,” said the 57-year-old who grew up on a farm in Bavaria in southern Germany. “Our approach is very simple: We have a background in agriculture, and we want to make the cheapest renewable molecules for the marketplace.”
Between 2001 and 2019, as renewable energy, especially biofuels, became more prominent as a way to cut carbon emissions, Verbio – founded and led by Sauter – built two ethanol plants, two biodiesel plants, and four RNG plants. Sauter said that Verbio started producing RNG from stillage in 2010 in Germany, where the company was founded. In India, Verbio uses rice straw to produce RNG.
Verbio’s approach combining RNG and ethanol production is unique, Sauter added. “Our intention is to grow with this unique set-up. The biggest challenge is to find available talent. We are looking for engineers to be a part of our company.”
Verbio was founded in 2006. The founders and their families own 72% of Verbio’s stock, which trades on the stock exchange in Frankfurt, Germany. Sauter describes himself as “a trader searching for new markets. The focus on having a lower CI is part of our DNA. We never fired our ethanol plants in Germany with coal.”
In 2015, the company decided to go global, Sauter noted, adding, “Our timing was perfect.”
He said Verbio considered purchasing Abengoa Bioenergy, which owned a cellulosic ethanol plant in Hugoton, KS. The plant opened in 2014 using wheat and corn stover as feedstocks and was designed to produce 25 million gallons of cellulosic ethanol a year. It was integrated with a 21-megawatt biomass-to-electric-power cogeneration plant.
Abengoa, the Spain-based parent company of Abengoa Bioenergy, filed for Chapter 11 bankruptcy protection in 2016 because of excess debts, and its assets were sold to satisfy creditors.
Verbio passed on purchasing the Abengoa plant, Sauter said, because the company felt it did not have sufficient knowledge of the U.S. renewable energy market at that time. By 2017, however, Verbio decided to enter the U.S. market for renewable fuels. “We were 99% sure it was a dead end to try to make ethanol from cellulose,” Sauter noted, so Verbio utilized the technology it developed for its European and Indian operations to make RNG from corn stover through an anaerobic digestion process.
Verbio’s Advantage
After purchasing the DuPont cellulosic ethanol plant in 2018, Verbio added anaerobic digesters to the plant and started to make RNG, which is cleaned and inserted into a natural gas pipeline operated by Alliant Energy Corp. that passes by the plant. Alliant provides regulated energy services to approximately one million electric and 425,000 natural gas retail customers in Iowa and Wisconsin.
“We also have a second process to produce additional RNG from wet stillage, a by-product of the ethanol production process, by putting it through anaerobic digestion to make biomass-based RNG to sell to other markets for processing as a feedstock for methanol, which can be made into renewable hydrogen,” Sauter explained.
DuPont equipped the plant to produce ethanol from corn stover. To make ethanol from corn kernels, Verbio needed to install grain receiving infrastructure, add corn storage, bring in hammer mills, and put in ethanol storage.
Capturing carbon dioxide from ethanol and RNG production to lower the plant’s carbon footprint also is being considered at the Nevada plant, he added. “We see big potential for marketing carbon dioxide, but we are not sure yet how or when it can be monetized.”
Jerry Perkins, contributing editor