Prime Candidates

Ethanol plants offer opportunities to expand carbon storage and utilization
By Kris Bevill | May 10, 2012

Last November, CO2 from the Archer Daniels Midland Co. ethanol plant in Decatur, Ill., began being captured, transported via pipeline and injected for permanent storage into a nearby geologic formation known as the Mount Simon Sandstone. The Illinois Basin-Decatur Project, which began being developed in 2007, is an effort being led by the Illinois State Geological Survey, the U.S. DOE, Schlumberger Carbon Services, and ADM and is the first of two carbon capture and storage (CCS) projects to be carried out at the site. The goal of the program, according to project leaders, is to prove that large amounts of CO2 from industrial sources can be compressed and injected into deep geological formations for storage, thus reducing greenhouse gas (GHG) emissions and lessening their effects on the environment. By mid-April, more than 100,000 metric tons of CO2 had already been injected at the site and operations were running smoothly. Injection will continue at a rate of 1,000 metric tons per day until the project concludes in the fall of 2014, by which time 1 million metric tons of CO2 is expected to have been injected into the deep reservoir for permanent storage.

In late 2013, a $208 million project, the Illinois Industrial Carbon Capture and Storage project, led by ADM, will begin operation. This second CCS project will adapt approaches of the IBDP and triple the site’s CO2 injection rate, representing the sequestration capacity necessary for commercial power generating facilities. Operating simultaneously, the projects will also provide researchers the opportunity to study the CO2 plumes and pressure fronts emanating from two injection wells. When the IBDP concludes in 2014, the second project will increase the injection rate up to 3,000 metric tons per day, amounting to 1 million metric tons annually, or approximately 95 percent of the CO2 that would otherwise be emitted from the ethanol plant’s fermentation process. By the end of 2015, when the ICCS project is scheduled to conclude, a total of 3.5 million metric tons of CO2 will have been geologically stored by the projects.

Location and Quality
The federal government has invested heavily in both CCS projects, providing funding for the first project through the Midwest Geological Sequestration Consortium under the DOE’s Regional Carbon Sequestration Partnerships and providing $141 million for the second project via the American Recovery and Reinvestment Act of 2009. The DOE is interested in CCS because it believes the process offers a way to reduce GHG emissions and mitigate climate change. But in order to advance the use of this technology, the economics of the operations first need to be proven. The two ADM projects will hopefully help achieve that goal. “One of the main reasons for DOE to fund these projects is to reduce the risks for the industry to demonstrate these first-of-a-kind technologies,” says Sai Gollakota, project manager at the DOE’s National Energy Technology Laboratory.

Ethanol plants are ideal suppliers for CCS activities because, unlike flue gas from power plants, the CO2 produced through ethanol fermentation is extremely pure and doesn’t require expensive scrubbing techniques to prepare the gas for geologic storage. “With our project, we’re showing that ethanol plants produce a very pure CO2 which only has to be dehydrated—the actual processing is very cost effective,” says Scott McDonald, biofuels development director at ADM. “The real cost for capturing CO2 from an ethanol plant is the compression. We believe this project will demonstrate that CO2 can be effectively captured from an ethanol plant and stored or used beneficially for other applications like enhanced oil recovery (EOR) while reducing the facility’s overall GHG emissions.”

The process of converting an ethanol plant’s CO2 from a gas destined for the earth’s atmosphere to a supercritical fluid that can be safely stored underground is a process that can be broken down into a few basic steps: capture, compression, dehydration and transportation. First, the wet CO2 gas is collected at the ethanol plant by a large centrifugal blower to boost the initial pressure before it is further compressed and dehydrated. Next, it is sent to an integrated compression and dehydration facility where the gas is dehydrated and compressed into a fluid state. Dehydration is necessary to prevent corrosion of the transportation pipeline, says McDonald. “Wet CO2 can convert over to carbonic acid, so we have to dry it to reduce the corrosive nature of the CO2,” he says. The compression and dehydration systems being used at the ADM site are both readily available pieces of technology that are commonly used in the oil and gas industries, says McDonald. “There really are no technical hurdles for what we’re doing.”

After the CO2 is dehydrated and compressed, it is piped a short distance to the injection site for storage. Because ADM’s Decatur plant happens to be located over Mt. Simon, the pipeline to transport CO2 from the facilities to the injection site is only about a mile long. Once there, the CO2 is sent to its final resting place via a 7,000-foot deep injection well drilled by Schlumberger Carbon Services. The CO2 becomes soluble with the reservoir’s brine (a concentrated solution that has a salt content five times greater than seawater) and is locked within the pores of the reservoir. Eventually, over hundreds of years, it will mineralize. “So when we inject the CO2 into the formation it eventually becomes permanently geologically stored,” McDonald says. While the economics may need some proving, Gollakota assures the injection practice has already been deemed very safe, noting that the Mt. Simon formation has already been used for natural gas storage for more than half a century and the depth at which the CO2 is being injected—approximately 7,000 feet below the surface—assures that drinking water will not be affected.

Enhanced Oil Recovery
Mt. Simon is anticipated to have room for perhaps billions of tons of CO2, but without carbon reduction mandates or some other regulatory initiative, there is no monetary incentive for ethanol producers to invest in CCS simply to store the gas. “If you have an EOR application where you can sell your CO2 to an oil producer, then you get revenue generation from the capture of the CO2 , which would help pay for that particular process,” says Gary Stiegel, director of major projects division at the National Energy Technology Lab.

CO2-EOR is a process in which CO2 is injected into aging oil fields to acquire oil reserves that wouldn’t otherwise be accessible. Several of these older fields lie within the range of many Midwestern ethanol plants. For example, southern Illinois has been a mature oil producing region of the state and could be a target CO2-EOR. Oil producers require large volumes of CO2 for EOR, but pipelines need to be built to economically meet this demand. Because of the cost to construct a regional pipeline to deliver CO2 to the southern part of the state, ethanol and oil would likely need a partner, or receive some other form of support, to facilitate construction.

With that in mind, the National Enhanced Oil Recovery Initiative provided Congress with a set of recommendations earlier this year aimed at encouraging greater use of CO2-EOR by offering incentives to companies that provide the gas for those activities. Included in those recommendations was a suggestion for Congress to modify an existing CO2 sequestration tax credit to make it more workable for applicants, a request to implement a 10-year tax credit provision for industrial sources and a recommendation that states should create policies to further incentivize the process. According to Brad Crabtree, policy director for the Great Plains Institute, one of the NEORI’s organizing groups, ethanol producers and other suppliers could use the incentives to alleviate the cost of building necessary pipelines. NEORI believes ethanol producers will be important early adopters for EOR expansion because of the low cost of carbon capture at those facilities and their proximity to applicable oil fields. He notes that while many ethanol producers currently sell CO2 for food and beverage applications, the market for EOR is significantly larger and also offers producers the opportunity to lower their carbon footprint. The federal tax credit proposed by NEORI would pay for itself in 10 years through increased federal revenues generated by additional oil production, according to the group, with an estimated net return of $100 billion over 40 years.

A small bipartisan group of congressional members immediately signed on to support NEORI’s suggestions, including Sen. Kent Conrad, D-N.D., who said the incentives would help reduce the nation’s “dangerous” dependency on foreign oil. ADM is also a participant in NEORI, along with several environmental groups and power providers. “ADM is one of the largest ethanol producers, and our plants are typically larger, so we concentrate a large amount of CO2 at any one of our locations,” McDonald says. “It makes sense to be part of that initiative because we feel that ethanol plants can be an economically attractive first step to supply CO2 for these applications. Our nation will continue to rely on fossil fuels and to make a significant contribution to the reduction of GHG emissions, CCS is going to be one of the low-carbon technologies needed in your portfolio.”

Author: Kris Bevill
Associate Editor, Ethanol Producer Magazine
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