Idaho Power and Rocky Mountain Power CPCN Application for Gateway West Segment E-8 Transmission Line

Office of the Secretary Service Date April 20, 2026

BEFORE THE IDAHO PUBLIC UTILITIES COMMISSION

IN THE MATTER OF IDAHO POWER ) CASE NOS. IPC-E-26-09 COMPANY AND PACIFICORP D/B/A ) PAC-E-26-06 ROCKY MOUNTAIN POWER'S ) APPLICATION FOR CERTIFICATES OF ) PUBLIC CONVENIENCE AND NECESSITY ) FOR SEGMENT E-8 OF THE GATEWAY ) NOTICE OF INTERVENTION WEST 500-KV TRANSMISSION LINE ) DEADLINE ) ) ORDER NO. 37010 On April 3, 2026, Idaho Power Company ("Idaho Power") and PacifiCorp d/b/a Rocky Mountain Power ("Rocky Mountain") (collectively the "Companies" or "each Company") applied to the Idaho Public Utilities Commission ("Commission") requesting a Certificate of Public Convenience and Necessity ("CPCN") for each Company permitting the commencement of construction for Segment E-8 of the Gateway West 500-kilovolt line ("kV") ("Segment E-8"), which will provide an additional 2,000 megawatts in transmission capacity ("Application"). Application at 2. The Companies request that this matter be processed by Modified Procedure and that the Commission issue each Company a CPCN no later than October 31, 2026. Id. The Commission now issues this Notice of Application and sets deadlines for interested persons to intervene.

YOU ARE HEREBY NOTIFIED that the Companies represent that Segment E-8 is a 133 mile long 500-kV line that will start at the Midpoint substation, near Jerome, Idaho, and will run to the Hemingway Substation, which is near Melba, Idaho. Id. at 4. Segment E-8 will also connect to Idaho Power's proposed 500-kV Mayfield substation. Id. A map illustrating Segment E-8 is included in the Direct Testimony of Jared L. Ellsworth Exhibit No. 2 that was filed with the Application. YOU ARE FURTHER NOTIFIED that the Companies represent that Segment E-8 will consist of approximately 540 lattice towers. Application at 10. Further, the Companies represent that the average distance between the towers will be between 1,200 to 1,300 feet and that the height of the towers will be anywhere between 145 to 199 feet. Id.

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YOU ARE FURTHER NOTIFIED that the Companies represent that Segment E-8 will add transmission capacity and deliver energy to the Treasure Valley from Mountain Home and Magic Valley, in addition to supporting transfers bilaterally between these regions. Id. at 5. The Companies represent that Segment E-8 will bolster transmission capability and support load growth and interconnection ability for new generation resources in the Magic Valley and Treasure Valley regions. Id. at 12. Idaho Power will hold 99 percent ownership in Segment E-8 and PacifiCorp will hold the remaining 1 percent. Id. at 5. YOU ARE FURTHER NOTIFIED that the Companies represent that pre-construction activities including a right-of-way granted by the Bureau of Land Management, various surveys, easements acquisition, and engineering designs, as well as permitting activity, have been going on since 2018. Id. at 8-9. The Companies represent that Segment E-8 construction will begin in October 2027 and will be completed in three phases. Id. at 11-12. Phases one and two will connect Hemmingway to Mayfield and Phase three will connect Mayfield to Midpoint. Id. at 12. Phase three is expected to begin in 2030. Id. YOU ARE FURTHER NOTIFIED that the Application and testimony are available for public inspection during regular business hours at the Commission's office. These documents are also available on the Commission's website at www.puc.idaho.gov. Click on the "ELECTRIC" icon, select "Open Cases," and click on the case number as shown on the front of this document. YOU ARE FURTHER NOTIFIED that all proceedings in this case will be held pursuant to the Commission's jurisdiction under Title 61 of the Idaho Code, and that all proceedings in this matter will be conducted pursuant to the Commission's Rules of Procedure, IDAPA 31.01.01.000

et seq.

YOU ARE FURTHER NOTIFIED that persons desiring to intervene in this matter to obtain parties' rights of participation must file a Petition to Intervene with the Commission pursuant to this Commission's Rules of Procedure 72 and 73, IDAPA 31.01.01.072 and -.073. Persons who wish to intervene as a party must file a Petition to Intervene no later than 21 days after the date of service of this Order. Such persons shall also provide the Commission Secretary with their email address to facilitate further communications. After the intervention deadline runs, the Commission Secretary shall issue a Notice of Parties that identifies the parties

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and assigns exhibit numbers to each party. Once the Notice of Parties has issued, Commission Staff shall informally confer with the Company and any intervening parties about how to further process this case and shall then report back to the Commission on a proposed case schedule. YOU ARE FURTHER NOTIFIED that persons who would like to present their views without parties' rights of participation and cross-examination do not have to intervene but may present their views by submitting written comments to the Commission. YOU ARE FURTHER NOTIFIED that the following people are designated as the Companies' representatives in this matter: For Idaho Power: For Rocky Mountain: Lisa Lance Joe Dallas Tim Tatum 925 NE Multnomah Street, Suite 2000 Connie Aschenbrenner Portland, OR 97232 1221 West Idaho Street (83702) joseph.dallas@pacificorp.com P.O. Box 70 Boise, ID 83707 Jana Saba llance@idahopower.com 1407 West North Temple, Suite 330 dockets@idahopower.com Salt Lake City, UT 84116 ttatum@idahopower.com jana.saba@pacificorp.com caschenbrenner idahopower.com ORDER IT IS HEREBY ORDERED that persons desiring to intervene in this matter must file a Petition to Intervene no later than 21 days from the service date of this Order. Once the deadline has passed, the Commission Secretary shall prepare and issue a Notice of Parties. IT IS FURTHER ORDERED that, after the Notice of Parties has issued, Commission Staff shall confer with the parties regarding a procedural schedule for this matter including, if necessary, a hearing in this matter. IT IS FURTHER ORDERED that parties comply with Order No. 35375, issued April 21,

1. Generally, all pleadings should be filed with the Commission electronically and will be deemed timely filed when received by the Commission Secretary. See Rule 14.02. Service between parties should continue to be accomplished electronically when possible. However, voluminous discovery-related documents may be filed and served on CD-ROM or a USB flash drive.

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DONE by Order of the Idaho Public Utilities Commission at Boise, Idaho this 20 day of th April 2026. __________________________________________ EDWARD LODGE, PRESIDENT __________________________________________ JOHN R. HAMMOND JR., COMMISSIONER __________________________________________ DAYN HARDIE, COMMISSIONER ATTEST: Monica Barrios-Sanchez Commission Secretary

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