Wes R. Wingen
Manager, Transmission Planning wes.wingen@blackhillscorp.com
March 9, 2012
Mr. David Franklin
Chair, WECC Technical Studies Subcommittee
Southern California Edison
1 Innovation Way
Pomona, CA 91768
409 Deadwood Avenue • PO Box 1400
Rapid City, SD 57709-1400
P: 605.721.2268
F: 605.721.2735
Mr. Enoch Davies
WECC Technical Staff
Western Electricity Coordinating Council
155 North 400 West, Suite 200
Salt Lake City, UT 84103
Re: Black Hills Power 2012 Annual Progress Report
Gentlemen:
Please find attached Black Hills Power’s 2012 Annual Progress Report on significant additions and changes to our system. The projects included in the report have no significant impacts on the
WECC interconnected system. Please contact me if you have any questions or concerns.
Sincerely,
Wes R. Wingen
Manager, Transmission Planning
Enclosure cc: Eric Egge – PCC Representative
Dan Baye – SRWG Representative
TSS Members

WECC Annual Progress Report for Black Hills Power 2012
Minnekhata 230 kV Substation:
The Minnekhata 230 kV substation is required to provide additional 230:69 kV transformation capacity in the southern Black Hills. The station will tap the existing Westhill-Osage 230 kV line approximately 9.7 miles from the Westhill substation and will include a 70 MVA 230:69 kV transformer. Reliability analysis for this project was initially performed as part of the 2008
BHBE LTP Study. Construction on the substation began in 2010 and was placed in-service during the fourth quarter of 2011.
St. Onge 230 kV Substation:
The St. Onge 230 kV substation project was identified to provide additional 230:69 kV transformation capacity in the northern Black Hills. The station will tap the existing Lange-
Lookout 230 kV line approximately 10 miles from the Lookout substation and will include a 150
MVA 230:69 kV transformer. Reliability analysis for this project was initially performed as part of the 2008 BHBE LTP Study. Construction on the substation has been delayed beyond 2014.
Teckla-Osage 230 kV Transmission Line:
The Teckla-Osage 230 kV line will consist of approximately 60 miles of 1272 ACSR ‘Bittern’ conductor on H-frame poles. The line will be constructed to provide needed Common Use
System (CUS) transmission capacity, accommodate projected load growth, and increase Wyodak area stability margins. Reliability analysis for this project was initially performed as part of the
2008 BHBE LTP Study. The Teckla-Osage line construction is scheduled to begin in 2013, and is expected to be complete in 2014.
Osage-Lange 230 kV Transmission Line:
The Osage-Lange 230 kV line will consist of approximately 75 miles of 1272 ACSR ‘Bittern’ conductor on H-frame poles. The line will be constructed to provide needed Common Use
System (CUS) transmission capacity and provide an additional path to the Rapid City load center. Reliability analysis for this project was initially performed as part of the 2008 BHBE
LTP Study as specified in Attachment K to the BHBE OATT. The Osage-Lange line construction is scheduled to begin in 2013. The project is still expected to be complete in 2015.
Reno Junction 200 MW Wind Farm:
The Reno Junction Wind Farm is a proposed generation project consisting of up to one hundred thirty-four (134) GE 1.5 MW wind turbines. The generation project will interconnect to the
Pumpkin Buttes 230 kV substation via a radial 230 kV line. The project has an executed LGIA that is currently under suspension. There are no changes to the status of this project from the
2011 WECC Annual Progress Report submittal.

WECC Annual Progress Report for Black Hills Power 2012
Weston Wind I 250.7 MW Wind Farm:
The Weston Wind I Wind Farm is a proposed generation project consisting of one hundred nine
(109) Siemens SWT-2.3-93 2.3 MW wind turbines. The generation project will interconnect to a new substation on the Wyodak-Osage 230 kV line approximately 6 miles northwest of the existing Osage power plant in Weston County, Wyoming. The customer has completed the
System Impact Study phase, and a Facilities Study Agreement has been tendered. The SIS report for this project was included in the 2011 WECC Annual Progress Report Submittal. The
Facilities Study Agreement was not returned and this project has been deemed terminated/complete.