More Green Downstream

Farmers using a new microbial nitrogen fertilizer from Pivot Bio have reduced carbon dioxide equivalent emissions by more than 932,500 metric tons since 2022. With feedstock accounting for half of the carbon intensity of a gallon of ethanol, the impacts of such products and measures could be enormous.

Drawn to the potential of alcohol-to-jet (ATJ) sustainable aviation fuel, the ethanol industry is mobilizing to reduce its carbon footprint to thresholds required in the Inflation Reduction Act, with most producers looking first to carbon capture. But reducing on-farm, or so-called “Scope 3” agricultural emissions has been a point of interest with many significant players—Cargill and ADM among them—looking to develop technologies and partnerships to reduce synthetic nitrogen use or get lower-carbon intensity fertilizer on the market and on farms.

“On-farm emissions, and their potential to lower future emissions could impact ethanol producer CI scores enough to fulfill the requirements of SAF feedstock,” says Mick Henderson, general manager of Commonwealth Agri-Energy in Hopkinsville, Kentucky. “Reduced use of fossil-based fertilizers ... could be the largest impact to on-farm CI scores, which could then impact the CI scores of ethanol plants that use their products as our feedstock.”

A surge in recent activity surrounding the development of low-CI fertilizer and microbial advancements that improve the uptake of nitrogen could help accelerate widespread emissions reductions in corn cultivation. The U.S. Department of Energy is playing no small part, providing funding of up to $36 million to kickstart research and market adoption.

Sustainable and Economical 
The U.S. DOE’s Advanced Research Projects Agency-Energy announced in July the Technologies to Emend and Obviate Synthetic Nitrogen’s Toll on Emissions (TEOSYNTE) program to lower the CI of corn and sorghum cultivation through the use of less synthetic fertilizer. The funding will support the development of technologies that help reduce nitrous oxide emissions by 50% from a 2009 baseline, the year with the highest level of greenhouse gas emissions recorded in the U.S., according to Steven Singer, ARPA-E program director.

“Also, lowering synthetic fertilizer will lower the costs of production for farmers,” Singer says. With the increased price of fertilizer impacting farm economies, Singer anticipates farmers will readily explore options to reduce usage. “I think farmers are pretty eager to see these technologies, but, of course, they want these technologies verified, and they want to know that these new biologicals will work for them.

“This is where an improvement in sustainability also will be an economic benefit. It’s not like the farmer will have to pay more to get the sustainability benefit,” Singer says. “If it works, they will actually save money, and that makes this approach particularly attractive.”
Proposals for the funding were due Aug. 13, and Singer anticipates announcing those selected for funding—approximately seven to nine projects—in early 2025.

“We decided to focus on corn and sorghum because today, in the U.S., those are the [primary] two crops that are made into ethanol,” Singer says. “Ethanol is approximately 10 percent of our transportation fuel for light-duty cars, and converting ethanol to a jet fuel is one of the pathways that is being looked at for sustainable aviation fuel.

“We wanted to focus on something that would be relevant to today’s energy system, and the production of ethanol is [exactly that], but also relevant to the future of liquid transportation fuels, which is sustainable aviation fuel.”

In particular, TEOSYNTE will focus on genetic manipulations of plants and microbes. “We’re using the inherent biology in the plants—corn and sorghum—and the microbes that associate with those plants to reduce the use of fertilizer and help the plants take up nitrogen more efficiently,” Singer says.

The research and development phase of TEOSYNTE is expected to take about four years. “At the end of four years, what we want is technologies that have been proven out in the field,” Singer says. “Then we’re looking to find pathways to the marketplace of these technologies and eventually to these farmers who plant these crops.”

Singer looks forward to reviewing proposals as the head of the program. “There are always people that you don’t anticipate coming up with really good ideas. That’s one of the exciting things about being a program director—you get to see all those ideas. I’m actually really excited.”

Complementing TEOSYNTE is ARPA-E’s Systems for Monitoring and Analytics for Renewable Transportation Fuels from Agricultural Resources and Management (SMARTFARM) initiative. For the past three years, the program has been developing large-scale data sets and new technologies to measure on-farm emissions including nitrous oxide. The technologies have been proven at lab scale and are now moving on to field testing.

On and Near the Market 
Meanwhile, Pivot Bio’s solutions are already in the field. Its flagship product is a seed treatment for corn that secures 25% of the crop’s nitrogen fertilizer needs at planting. The company also produces a microbial nitrogen fertilizer that reduces the amount of synthetic nitrogen fertilizer required to achieve target yield.

“Emissions are avoided upstream through a manufacturing process that results in 99% fewer emissions, midstream with streamlined transportation, and on the farm with reduced nitrous oxide volatilization,” says Mitchell Craft, Pivot Bio spokesperson.
Pivot Bio’s microbes provide ammonia in small amounts to the roots of crops where it is directly taken up by the plant. “Our microbial fertilizer also results in a larger root mass, which improves the uptake of added nitrogen and phosphorus, further improving the efficient uptake of nutrients, reducing loss,” Craft says.

Craft says Pivot Bio focuses on the quantity of synthetic nitrogen applied to corn and sorghum because it’s the only method with scientific consensus to reduce nitrous oxide emissions. “Reducing N2O emissions by replacing synthetic nitrogen fertilizer with biological approaches will improve the sustainability of ethanol production from corn and sorghum, reducing GHG emissions in agriculture and lowering the CI of both ethanol fuel and ethanol-derived SAF.”

The company also boasts its N-OVATOR program, which connects farmers with companies looking to achieve Scope 3 emissions reduction goals through purchasing credits. It’s a way to bring a new revenue stream to farmers for growing more sustainable crops, Craft says. The largest transaction to date through the program was 100,000 nitrogen credits to a global food and beverage company, representing 100,000 metric tons of carbon dioxide equivalent, avoided by more than 450 farmers across 300,000 acres. “In total, the growers in this insetting partnership replaced over 10 million pounds of synthetic fertilizer,” Craft cites.

Similarly, POET and CF Industries Holdings Inc. in July announced their collaboration to advance the production and use of low-carbon ammonia fertilizer. Citing ammonia’s significant impact on the lifecycle CI of corn and ethanol, the companies announced they will begin demonstrations this fall and into spring 2025, using CF Industries’ green ammonia from its Donaldsonville Complex in Louisiana. Green ammonia, according to CF Industries, is produced with hydrogen sourced from an electrolysis-based production process that emits no carbon dioxide. This low-carbon ammonia can reduce the CI of ethanol up to 10%, according to the companies’ joint press release. 

The partners also announced intentions to develop a low-carbon fertilizer supply chain to track, validate and certify CI reductions through use of the low-carbon ammonia. “This includes implementing supply plans with fertilizer retailers serving farms that supply corn to these POET bioprocessing plants, and developing monetization opportunities for farmers that use this low-carbon fertilizer,” the joint press release states.