South Dakota PUC Reviews Otter Tail’s 71-Mile Transmission Line Project Through Grant and Roberts Counties; Public Meeting Set for October
Northeast Radio SD News – Milbank, SD - The South Dakota Public Utilities Commission has begun formal review of Otter Tail Power Company’s application to build a major new 345‑kilovolt transmission line across Grant and Roberts counties, a project that would span roughly 71 miles from the Big Stone South Substation west of Big Stone City to the North Dakota border northeast of New Effington.
The filing, submitted September 8, triggers the state’s facility‑permit process under SDCL 49‑41B. The proposed line is part of the larger Big Stone South to Hankinson to Bison (BSSHB) regional transmission upgrade, jointly planned by Midcontinent Independent System Operator (MISO) and Southwest Power Pool (SPP) to improve grid reliability and support future generation interconnections.
Confidentiality Request Filed for Cultural Review
In a separate filing, Otter Tail requested confidential treatment for Appendix F, the project’s Level I Cultural Resources Review. The company said the appendix contains information provided by the South Dakota State Historic Preservation Office that must remain confidential under SDCL 1‑20‑21.2. The filing asks the PUC to protect the material for the life of the docket and return it to the project once proceedings conclude.
“Appendix F… must remain confidential pursuant to SDCL 1‑20‑21.2,” the filing states.
Company Requests Up to 12‑Month Extension
Otter Tail also filed a motion to extend the statutory deadline for the Commission to issue a decision. Under SDCL 49‑41B‑24, the PUC must rule within 12 months of an application’s filing — in this case, by September 9, 2027. The company is requesting up to an additional 12 months, citing seasonal constraints and ongoing environmental and cultural surveys that may not be completed until summer 2027.
“Some of these surveys may not be completed until the Spring or Summer of 2027,” Otter Tail wrote, adding that landowner access and right‑of‑way acquisition work is still underway.
The company emphasized that it filed the application before the statutory deadline to preserve its first‑right status as the incumbent transmission owner under SDCL 49‑32‑20.
PUC Issues Public Notice, Sets Input Meetings
On September 11, the Commission issued its Notice of Application, formally opening docket EL26‑028 and scheduling two public input meetings:
· Milbank — Wednesday, October 21, 2026, 5:30 p.m.
· Rosholt — Thursday, October 22, 2026, 11:00 a.m.
The notice outlines the project’s scope, including:
· 71 miles of new 345 kV line
· Steel monopole structures
· Substation modifications at Big Stone South
· A 150‑foot right‑of‑way
· Estimated construction cost between $190.6 million and $228.7 million
· Construction beginning in 2030 and completion in 2033
The Commission also announced that applications for party status are due by November 9, 2026.
“For approval, Applicant must show that the proposed Project will comply with all applicable laws and rules, will not pose a threat of serious injury to the environment… and will not unduly interfere with the orderly development of the region,” the notice states.
Agencies Already Engaged
Appendix B of the application shows extensive early coordination with federal and state agencies, including the FAA, FHWA, U.S. Fish and Wildlife Service, NRCS, and multiple tribal governments. The FAA advised Otter Tail that structures near Sisseton Municipal Airport may require formal obstruction‑evaluation filings, while FHWA noted that the project’s crossing of Interstate 94 in North Dakota will likely require an Interstate Use Agreement and NEPA review.
What Comes Next
The PUC will gather public comment at the October meetings before setting a procedural schedule. A formal evidentiary hearing may follow in 2027. The Commission has not yet ruled on Otter Tail’s request to extend the statutory deadline.
