Idaho Power Annual Marginal Pricing Update, Order 37007

Office of the Secretary Service Date April 17, 2026

BEFORE THE IDAHO PUBLIC UTILITIES COMMISSION

IN THE MATTER OF IDAHO POWER ) CASE NO. IPC-E-26-08 COMPANY'S APPLICATION FOR ITS ) ANNUAL UPDATE TO MARGINAL ) PRICING USED IN CERTAIN SCHEDULES ) ) NOTICE OF INTERVENTION ) DEADLINE ) ) ORDER NO. 37007

On April 1, 2026, Idaho Power Company ("Company") applied ("Application") to the Idaho Public Utilities Commission ("Commission") requesting acknowledgement that the updated marginal cost calculations provided in the Application were correctly quantified, a finding that the Company complied with Order No. 36619 by meeting with Commission Staff ("Staff") in advance of this Application, and authorization to maintain the currently in-effect marginal energy price components of Schedule 20, Speculative High-Density Load ("Schedule 20") and Schedule 34, Lamb Weston Special Contract ("Schedule 34"). The Commission now issues this Notice of Application and sets deadlines by which interested persons may intervene.

YOU ARE HEREBY NOTIFIED that the Company calculated updated marginal energy prices using two Commission-approved methodologies--the Two Run Method and the Single Run Method--with detailed results provided in Attachment 3 to the Application. Application at 11-12. YOU ARE FURTHER NOTIFIED that consistent with prior Commission directives in Case Nos. IPC-E-23-18 and IPC-E-25-17, the Company implemented the Two Run Method by conducting two AURORA model simulations: a base case reflecting expected system conditions and a second scenario incorporating an incremental 15 megawatts ("MW") of load. Id. at 12. The marginal cost of energy was then derived by calculating the difference in total system costs between these two simulations and expressing that difference on a per-MW-hour basis. Id. YOU ARE FURTHER NOTIFIED that the Company applied the Single Run Method in accordance with Commission-approved methodology by performing a single AURORA simulation for the test year. Id. This simulation incorporated the Company's projected system load,

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excluding load already priced under the Single Run Method, and included an additional 100 MW to approximate marginal conditions. Id. The Company represented that, at present, this methodology is applied solely to Schedule 28, Micron FAB, as there are no active customers under Schedule 20. Id. YOU ARE FURTHER NOTIFIED that upon evaluating the outcomes of both methodologies, the Company stated that the resulting marginal cost-based energy rates were lower than the embedded power supply cost rates projected for the 2026-2027 Power Cost Adjustment test year. Id. The Company argued that without mitigation, customers billed under marginal cost- based rates would, on average, pay less than customers charged under embedded cost-based rates.

Id. The Company believes that the observed disparity raises concerns that current methodologies

may not fully capture all relevant incremental costs, particularly long-run marginal costs such as those associated with power purchase agreements. Id. at 12-13. YOU ARE FURTHER NOTIFIED that the Company recommended that the Commission direct the Company to maintain the currently effective marginal cost-based energy rates for Schedules 20 and 34 as a mitigation measure. Id. Alternatively, should the Commission determine that updated rates should be implemented based on the approved methodologies and supporting analysis in Attachment 3, the Company indicated that it would file revised tariff sheets reflecting those updated rates in a subsequent compliance filing. YOU ARE FURTHER NOTIFIED that the Application is available for public inspection during regular business hours at the Commission's office. The Application is 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.

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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 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 Company's representatives in this matter: Megan Goicoechea Allen Grant T. Anderson Donovan Walker Austen Apperson IPC Dockets Jessi Brady 1221 West Idaho Street (83702) 1221 West Idaho Street (83702) P.O. Box 70 P.O. Box 70 Boise, ID 83707 Boise, ID 83707 mgoicoecheaallen@idahopower.com ganderson@idahopower.com dwalker@idahopower.com aapperson@idahopower.com dockets idahopower.com brad 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

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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. DONE by Order of the Idaho Public Utilities Commission at Boise, Idaho this 17 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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