Secretary Naig visits Iowa Select, learns about methane digesters

On Friday, Iowa Secretary of Agriculture Mike Naig visited with representatives of Iowa Select Farms (ISF) and Roeslein Alternative Energy (RAE), LLC, to learn more about the two companies’ partnership in utilizing methane digesters to make a renewable natural gas source.

Prior to touring the ISF site that sits on the Clarke-Union County lines, a presentation was given at AmericInn in Osceola on the project.

Project background

ISF Director of Nutrition Ben Haberl spoke about the local ISF site, known as Ponderosa. An older location, there are five sow farms that have roughly 25,000 sows. There are about 10,000 more pigs in separate gilt development units and a truck washing facility all at the Ponderosa location.

Haberl said that the age of the site’s location played a factor in deciding to pursue upcycling of the methane, as well as added benefits to environmental and social factors. From the reduction of greenhouse gases emissions to eliminating the rainwater that would collect in the open lagoons to better neighborly relations, the project seemed the way to go.

“The volume of manure, the big take home is eliminated the rain water in the [lagoons],” Haberl said. “Obviously the value in being a good neighbor with the odor and some of the things that provides as well.”

Using a digester also cuts down on having to haul away the water in the lagoons.

In 2022 RAE began work with ISF to build a digester plant, and covered the existing lagoons to begin capturing the biogas. The 2022 ISF Sustainability Report estimated that about 40,500 Million British Thermal Units (MMBtus) of methane per year would be captured from the lagoons, with about 38,000 MMBtus of that being quality enough to be injected into pipelines. ISF began being able to capture and clean the gas for sale in mid-2023.

RAE’s role

Development manager for RAE Will Higgins spoke about RAE, stating that the company has completed about 135 covered lagoon digester projects across the United States with 100 more in process.

“We really appreciate the focus and leadership from Gov. Reynolds and legislatures on this industry in Iowa, and we’re really excited about the growth opportunities,” said Higgins. “Marketing the gas and generating revenue from the manure, we’ve been a pioneer in that space from the pathways to secure that revenue through both the EPA renewable fuel standard and also California’s renewable fuel standard.”

Higgins shared that RAE has recently launched a micro-gas processing unit that operates similarly to larger scale units but now can be used by smaller farms. He talked of other work the company is doing across the state, including research into different forms of producing renewable natural gas and providing cover crop and conservation practices. A metric for conservation he noted is that over the next four years, RAE is going to plant about 41.5 million milkweed seeds across the state.

“That’s so important for monarchs - Iowa has done a lot around habitat with that, it’s critically important. One of those ancillary benefits folks aren’t thinking of,” Naig said.

How the process works

While there are different varieties of methane digesters available, Higgins described the way the one at ISF works.

The first step is collecting the manure produced from the pigs into a lagoon. In the case of the Ponderosa site, there were already a lagoons in place that was just open to the air. RAE placed a cover over the top that acts like a balloon, inflating as it fills with gas. That gas is taken and cleaned up, then it is trucked out to be injected into a pipeline in northern Missouri. From there, the gas is used to power and heat houses and buildings as a form of renewable natural gas.

“...those were pits that were open, they’re there anyway, that activity’s going to happen. That’s the reality of livestock production…By putting the cap on that and capturing it and upcycling and making it renewable natural gas, you just added a value stream to this whole process,” said Naig.

The initial methane gas at ISF is taken from about 65% methane, 35% CO2 and a bit of hydrogen sulfide and cleaned up to be 100% methane to meet all gas quality standards for natural gas that can be used by consumers. The amount of energy produced is the equivalent to powering roughly 2,500 homes. Since the Ponderosa site is not connected to a pipeline, the gas is stored over the winter months; if it were connected to a pipeline, they would sell year-round.

Benefits and future outlook

It’s not just reducing methane emissions, improving neighbor relations or increased revenue that are benefits of the methane digesters.

“Energy dominance, energy security, Iowa is poised to be a huge player. We’re number one in a lot of things, we could be number one in this, too,” said Higgins.

The use of cereal rye in helping to create the biomass - renewable organic material that comes from plants and animals - adds benefit with cover crop and conservation, both of which Iowa is working to increase. Higgins estimated that the mix of material in the biomass is about 50/50 by volume.

“The importance of that is huge. [With] cover corps you get so many benefits. But also it is an additional cost - management costs, seeds…overtime, just by improving soil health alone, that will pay back,” said Naig, who added that he liked that value can be added to farmers or facilities who invest in having digesters. “We talk about using cover crops for forage, for livestock, you can assign a value to that…this…I can invest in a piece of equipment that [the digester] might need…now I’ve got a payback.”

On Feb. 13, RAE was notified that they had received ISCC and ISCC Plus certifications, an international sustainability certification. By achieving this certification, RAE is now able to sell renewable natural gas on the international market; the plus certification allows selling to United States buyers.

“It’s not that manure doesn’t have value - it does. It’s not a free product lying around,” said Naig.

In closing, Haberl reiterated that the age of the ISF site was a major factor in starting the project, with the need to be on the cutting edge for some of these opportunities as one looks at the future lifetime of the location.

“We’ve learned a lot in this process…to this point, unless cattle or something along those lines, the rye or the cover crops largely just get burnt down…to provide revenue streams to farmers that way. As we continue down the full life cycle-type assessments of those things, how do we have that play long-term,” said Haberl.

“If you can close those loops…cover crop fed into digester, potentially lowers the [carbon intensity] score being fed to the pigs…I think it’s really a great story,” said Naig.