20251231Tariff Advice No. IPC-TAE-25-04.pdf

0-10AHO POWER.
RECEIVED
DECEMBER 31, 2025
IDAHO PUBLIC
GRANT T.ANDERSON UTILITIES COMMISSION
Pricing and Tariff Manager
ganderson(Didahopower.com
VIA ENCRYPTED ELECTRONIC MAIL
December 31, 2025
Commission Secretary
Idaho Public Utilities Commission
11331 W. Chinden Blvd., Bldg 8,
Suite 201-A (83714)
PO Box 83720
Boise, Idaho 83720-0074
Re: Tariff Advice No. 25-04
Annual Compliance Filing to Update the Substation Allowance Amount under
Rule N
Dear Commission Secretary,
Idaho Power Company ("Idaho Power" or"Company") hereby submits its proposed
update to the Substation Allowance amount outlined in Rule N, Special Arrangements for
Substation Allowances and Transmission Vested Interest (previously contained in
Schedule 19, Large Power Service ("Schedule 19"). This annual compliance filing
updates the Substation Allowance amount, as required by Idaho Public Utilities
Commission ("Commission") Order Nos. 32893 and 32914. The following tariff sheet
identifies the proposed modification:
First Revised Sheet No. N-3 Cancelling Original Sheet No. N-3
In Case No. IPC-E-25-16, the Commission issued Order No. 36892, approving
the Settlement Stipulation that moved the substation allowance and transmission vested
interest provisions from Schedule 19 to newly established Rule N, effective January 1,
2026. Consistent with that Order, this tariff advice seeks to update the Substation
Allowance under Rule N, with an effective date of March 15, 2026. Future annual
compliance filings will accordingly be filed under Rule N.
The cost estimation methodology the Company used in this tariff advice is the
same methodology approved by the Commission in Case No. IPC-E-13-09 and
subsequent annual filings.
P.O.Box 70(83707)
1221 W.Idaho St.
Boise,ID 83702

Commission Secretary
December 31, 2025
Page 2 of 2
The proposed Substation Allowance amount reflects updated material costs, labor
rates, and the stations overhead rate, which in total results in the proposed per megawatt
Substation Allowance amount increasing from $99,826 to $104,806, or by approximately
5 percent. The primary drivers behind the proposed increase are increased material
costs that have resulted in an approximate 2 percent increase in the cost of the 4-unit
metalclad switchgear and an approximate 5 percent increase in the cost of the
138kV/13.09kV, 44.8 MVA transformer. The increases in the costs of these items in
addition to an increase in the stations overhead rate from 2.64 percent to 3.36 percent
contribute to the overall increase in the substation allowance.
The workpapers used to calculate the per megawatt Substation Allowance amount
and the stations overhead rate are provided as confidential attachments to this tariff
advice. Please note that information in the workpapers is commercially sensitive and, if
disclosed freely, could subject Idaho Power or its customers to risk of competitive
disadvantage or other business injury.
Because the Company files to update the Substation Allowance in accordance with
a previously approved Commission methodology, it has submitted the request as a tariff
advice. However, to ensure Staff has adequate time to complete its review,' the Company
is requesting the same effective date proposed by Staff in the 2023 update. Accordingly,
the Company respectfully requests that the proposed updates are approved and become
effective by March 15, 2026.
If you have any questions regarding this tariff advice, please contact Senior
Regulatory Analyst Ashley Herrera at 208-388-2656 or aherrera(aD_idahopower.com.
Sincerely,
1, �IIG�G/lddK.
Grant T. Anderson
GTA:sg
Enclosures
' In the 2023 filing, the Company submitted IPC-TAE-23-03 with a proposed effective date of February 1,
2024. Staff recommended the Commission treat the Company's Tariff Advice as an application to allow a
more in-depth analysis to ensure the components included in the allowance calculation reflect current,
accurate costs. To provide that time, Staff recommended the Commission suspend the Company's
proposed effective date until March 15, 2024. The Commission adopted Staff's recommendation and
opened Case No. IPC-E-24-02.

CERTIFICATE OF ATTORNEY
ASSERTION THAT MATERIALS REQUESTED AND PROVIDED DURING THE
COURSE OF AN IDAHO PUBLIC UTILITIES COMMISSION PROCEEDING
ARE PROTECTED FROM PUBLIC INSPECTION
Tariff Advice No. IPC-TAE-25-04
Idaho Power Company's Annual Compliance Filing to Update the Substation
Allowance Amount Under Rule N
The undersigned attorney, in accordance with Commission Rules of Procedure 67,
believes that the attachments to Idaho Power Company's Tariff Advice No. 25-04 — Idaho
Power Company's Annual Compliance Filing to Update the Substation Allowance Amount
Under Rule N, dated December 31, 2025, contain information that constitutes trade
secrets or other confidential business data exempt from disclosure under Idaho Code §
74-101, et seq., and/or § 48-801, et seq. As such, it is protected from public disclosure,
inspection, examination, or copying.
DATED this 31 st day of December 2025.
Lisa C. Lance
Counsel for Idaho Power Company
P.O.Box 70(83707)
1221 W.Idaho St.
Boise,ID 83702

Idaho Power Company First Revised Sheet No. N - 3
Cancels
I.P.U.C. No. 30, Tariff No. 101 Original Sheet No. N - 3
RULE N
SPECIAL ARRANGEMENTS
FOR SUBSTATION ALLOWANCES AND
TRANSMISSION VESTED INTEREST
(Continued)
Transmission Vested Interest Portion is that part of the Company's transmission system in which
a Transmission Vested Interest is held.
Substation Allowance
If a Schedule 9 or 19 Customer's request for service requires the installation of new or upgraded
transformer capacity in Substation Facilities, the following considerations will be included in the separate
agreement between the Customer and the Company:
The Customer will initially pay for the cost of new or upgraded Substation Facilities
required because of the Customer's request. The Customer will be eligible to receive a one-time
Substation Allowance based upon subsequent sustained usage of capacity by the Customer.
a. Substation Allowance: The maximum possible allowance will be
determined by multiplying the Customer's actual increase in load by$104,806 per MW but
will not exceed the actual cost of the Substation Facilities.
b. Substation Allowance Refunds: The Substation Allowance will be refunded
to the Customer over a five-year period, with annual payments based on the Customer's
Basic Load Capacity at the time of refund. The first refund will be paid one year following
the first month energy is delivered through the new Substation Facilities.
The refunds will occur based on the following adjustment, which will be
added to the Substation Allowance received in the previous year. If there is no
change in load from the previous year, the Substation Allowance for that year is
equal to the Substation Allowance from the previous year:
((Change in load from the previous year as measured in MW)x(Substation Allowance per MW))
Number of Substation Allowance Refunds remaining in five-year period
The Customer's annual refunds will be made in accordance with the
Substation Allowance amount stated in the separate construction agreement
between the Customer and the Company.
Transmission Vested Interest
If a Schedule 9 or 19 Customer's request for service requires the installation of new or upgraded
capacity in Transmission Facilities, and those Transmission Facilities are serving the Customer by a
radial feed, the following considerations will be included in the separate agreement between the
Customer and the Company:
The Customer will initially pay for the cost of new or upgraded Transmission Facilities required
because of the Customer's request. The Customer may be eligible to receive Transmission Vested
Interest Refunds in accordance with Schedule 9 or 19.
IDAHO Issued by IDAHO POWER COMPANY
Issued - December 31, 2025 Timothy E. Tatum, Vice President, Regulatory Affairs
Effective— March 15, 2026 1221 West Idaho Street, Boise, Idaho
Advice No. 25-04

Idaho Power Company First Revised Sheet No. N - 3
Cancels
I.P.U.C. No. 30, Tariff No. 101 Original Sheet No. N - 3
RULE N
SPECIAL ARRANGEMENTS
FOR SUBSTATION ALLOWANCES AND
TRANSMISSION VESTED INTEREST
(Continued)
Transmission Vested Interest Portion is that part of the Company's transmission system in which
a Transmission Vested Interest is held.
Substation Allowance
If a Schedule 9 or 19 Customer's request for service requires the installation of new or upgraded
transformer capacity in Substation Facilities, the following considerations will be included in the separate
agreement between the Customer and the Company:
The Customer will initially pay for the cost of new or upgraded Substation Facilities
required because of the Customer's request. The Customer will be eligible to receive a one-time
Substation Allowance based upon subsequent sustained usage of capacity by the Customer.
a. Substation Allowance: The maximum possible allowance will be
determined by multiplying the Customer's actual increase in load by $99,826104,806 per
MW but will not exceed the actual cost of the Substation Facilities.
b. Substation Allowance Refunds: The Substation Allowance will be refunded
to the Customer over a five-year period, with annual payments based on the Customer's
Basic Load Capacity at the time of refund. The first refund will be paid one year following
the first month energy is delivered through the new Substation Facilities.
The refunds will occur based on the following adjustment, which will be
added to the Substation Allowance received in the previous year. If there is no
change in load from the previous year, the Substation Allowance for that year is
equal to the Substation Allowance from the previous year:
((Change in load from the previous year as measured in MW)x(Substation Allowance per MW))
Number of Substation Allowance Refunds remaining in five-year period
The Customer's annual refunds will be made in accordance with the
Substation Allowance amount stated in the separate construction agreement
between the Customer and the Company.
Transmission Vested Interest
If a Schedule 9 or 19 Customer's request for service requires the installation of new or upgraded
capacity in Transmission Facilities, and those Transmission Facilities are serving the Customer by a
radial feed, the following considerations will be included in the separate agreement between the
Customer and the Company:
The Customer will initially pay for the cost of new or upgraded Transmission Facilities required
because of the Customer's request. The Customer may be eligible to receive Transmission Vested
Interest Refunds in accordance with Schedule 9 or 19.
IDAHO Issued by IDAHO POWER COMPANY
Issued per Order No- December 31, 2025- Timothy E. Tatum, Vice President, Regulatory Affairs
Effective— March 15, 2026 january , 1221 West Idaho Street, Boise, Idaho
Advice No. 25-04