Summit CCUS project expands pipe diameters, faces delays

Feb. 6, 2023
Summit Carbon Solutions has increased the planned diameter of many of the sections of its proposed 2,000-mile Midwest Carbon Express CO2 pipeline, raising its capacity to 18 million tonnes/year (tpy).

Loren G. Flaugh
Primghar, Iowa

Summit Carbon Solutions has increased the planned diameter of many of the sections of its proposed 2,000-mile Midwest Carbon Express CO2 pipeline, raising its capacity to 18 million tonnes/year (tpy). A briefing from Summit stated that “these significant pipeline diameter increases were…done to ensure we have enough capacity to meet any additional demand for service without having to come back to do any future surveying.  We will also not have to increase any already buried pipe sizes in the future.” She concluded by noting that existing route easements will not change and that the pipeline’s capacity in Iowa alone would be 12 million tpy.

Summit has firm commitments from 32 Midwest ethanol plants and one fertilizer production company to pump CO2 into Summit’s carbon capture, utilization, and storage (CCUS) pipeline gathering system for shipment to three North Dakota underground storage sites.  The company filed a pipeline diameter revision with both the Iowa Utilities Board (IUB) and the South Dakota Public Utilities Commission (PUC) at about the same time in first-half October 2022. 

Summit wanted the South Dakota PUC’s 10-day evidentiary hearing to convene in mid-April 2023 so that a final decision could be made by June 15. Summit requested an extension of this timeline to June 15, 2023, on May 9, 2022. The PUC granted an indefinite extension instead. Summit’s attorneys claimed that this action was outside the commission’s authority and Summit said it anticipated project construction to start late third-quarter 2023.

On Jan. 9, 2023, however, the South Dakota PUC announced that the evidentiary hearing would be held Sept. 11-22, 2023. Summit’s lawyers and lawyers for the seven South Dakota ethanol plants contracted with Summit expressed their disappointment. And on Jan. 20, 2023, Sunset filed a three-page letter with the South Dakota PUC requesting the commission reconsider its scheduling order and instead adopt the proposed mid-April timing.

An earlier letter from Summit’s attorneys detailed “practical considerations” that would result from a docket extending past June 15, 2023, and subsequent delay of construction start to Apr. 1, 2024. These included:

  • Clearing Restrictions. Starting construction in August 2023 would allow more time for clearing vegetation within the Migratory Bird Treaty Act’s mid-July to end-February annual window, also reducing the duration of construction for landowners.
  • Construction. Completing construction in a single window starting in 2024 (rather than splitting it into two seasons as had been planned), would require additional spreads and both more personnel and increased construction traffic. It would also complicate water disposal by moving hydrotesting and commissioning to winter 2024-25, requiring anti-freezing additives and their being hauled off premises.
  • Material issues. A second-quarter 2024 construction start would result in materials being on the ground for substantially longer before being installed, increasing risk of corrosion or damage.
  • Non-environmental permits. Expiring permits will require refiling, increasing the burden on townships, counties, and other permitting entities.
  • Tax Implications. A delayed in-service date would lead to a corresponding delay in local economic benefits.
  • Ethanol plants-45Q. Failure to be in service by end-2024 would reduce the 45Q sequestration benefits for the ethanol plants involved.


Summit’s CCUS mainline essentially parallels Energy Transfer Partners LP’s 30-in. OD Dakota Access Bakken crude oil pipeline, built through northwest Iowa, South Dakota, and into North Dakota in 2016.  

A new project route map shows a 12-in. OD trunkline coming from the south and merging at a western O’Brien County, Iowa, valve site with a 20-in. OD mainline pipe coming from the east and a 24-in. OD mainline heading west. The diameters of each of these lines are 4 in larger than before the October 2022 revisions. 

On the schematic, mainlines are pipelines that carry CO2 to the sequestration sites. Trunklines are pipelines that will carry CO2 from ethanol plants to mainlines or from lateral pipelines to the mainline.  Lateral pipelines are the smaller diameter pipelines that carry CO2 from each ethanol plant to the trunkline. 

The detailed project schematic drawing also shows the number of proposed mainline and trunkline pump stations.  Three pump stations are planned for the mainline through Iowa, with four along the 24-in. OD South Dakota mainline, and one in North Dakota, southeast of the underground sequestration site.  Pump stations along the trunklines include two in Iowa, two along a much larger 20-in. OD trunkline going southwest through Nebraska, and another in eastern North Dakota west of Fargo along the 12-in. OD line.

Engineering specifications

Pipeline construction will use high-strength carbon steel pipe.  Based upon volume requirements and pressure service, pipe segments will range in size from 4- to 24-in. OD and have 0.189-0.750-in. WT.

Maximum operating pressure (MOP) will be 2,183 psig.  Maximum operating temperature is 120° F., with a maximum design flow rate of 936 MMscfd (~18 million tpy).  The design of the whole pipeline system is based on a maximum 2,150-psi discharge pressure at pump stations and carbon capture sites.

Summit plans to install Ariel Corp. reciprocating compressors at the 32 ethanol-plant carbon capture collection sites. Each will use one, two, or three compressors based on CO2 production volume, with the 52 compressors planned in total.

A recent Summit press release indicated that a Summit Carbon Solutions team had visited a Colorado Ariel Manufacturing facility to see the first test run of the reciprocating carbon-capture compressor equipment.

All pump station sites will be purchased from the landowners along the permanent easements. Pump station sites will have a security fence along the property line with all pumps and major equipment installed within a shelter.  Each pump station will contain up to 4 pumps driven by electric motors, an electrical building, electrical substation, a pump building, communications equipment, and an employee parking area.  

Electricity for each station will be purchased from the local power distribution company.  Installed power could be 4,000-6,000 hp including a fully redundant hot spare pump and motor.  Actual power usage will range between 2,000 and 3,000 hp, requiring 1,500-2,500 kw of electricity. Pump stations will be fully automated for unmanned operations.  Remote start-stop setpoint controls, unit monitoring equipment, and station information will be at each site.

Summit is evaluating communications systems.  Remote valve sites will use a cell modem with satellite backup for communications with the operations control center in Ames, Iowa. For the pump stations, a local internet service will provide communications where practical with cell modem or satellite backup. It’s expected that reliable communications can be established without any communications towers being taller than 50 ft.

A real-time transient model (RTTM) leak detection system will run parallel to the pipeline.. The RTTM is a real-time hydraulic model of the pipeline system.  If the behavior of the pipeline does not match the hydraulic model, the ops center will be notified that an issue requires analysis. Alarms will sound for pipeline control operators when this analysis detects a potential leak along the system.

Regulatory approval

The last test facing Summit’s CCUS project is to gain approval from all five state and federal regulatory agencies. This process could begin second-quarter 2023 when the IUB is likely to hold its final public hearing to determine whether or not Summit’s $4.5 billion pipeline will begin construction this summer.

As of early January 2023, Summit was adamant that South Dakota needed to reach a decision on its permit application by June 15, 2023, so that right-of-way clearing could begin in August. Subsequent construction would run through the 2023-24 winter to meet a late-2024 target for system startup if the pipeline is approved in all five states it would cross.