20251218Reply Comments.pdf

0-10AM POWER.
LISA C. LANCE RECEIVED
Corporate Counsel December 18, 2025
Ilance6a idahopower.com IDAHO PUBLIC
UTILITIES COMMISSION
December 18, 2025
VIA ELECTRONIC FILING
Commission Secretary
Idaho Public Utilities Commission
11331 W. Chinden Blvd., Bldg 8,
Suite 201-A (83714)
PO Box 83720
Boise, Idaho 83720-0074
Re: Case No. IPC-E-25-31
Application of Idaho Power Company for Approval or Rejection of an Energy
Sales Agreement with Fossil Gulch Wind Park, LLC for the Sale and
Purchase of Electric Energy from the Fossil Gulch Wind Park
Dear Commission Secretary:
Attached for electronic filing please find attached Idaho Power Company's ("Idaho
Power") Reply Comments in the above matter.
If you have any questions about any of the aforementioned documents, please do
not hesitate to contact me.
Ve
ry truly yours,
(jLisa C. Lance
LCL:sg
Attachment
1221 W. Idaho St(83702)
P.O. Box 70
Boise, ID 83707

DONOVAN E. WALKER (ISB No. 5921)
LISA C. LANCE (ISB No. 6241)
Idaho Power Company
1221 West Idaho Street (83702)
P.O. Box 70
Boise, Idaho 83707
Telephone: [phone]
Facsimile: [phone]
(lance idahopower.com
dwalker(a)idahopower.com
Attorneys for Idaho Power Company
BEFORE THE IDAHO PUBLIC UTILITIES COMMISSION
IN THE MATTER OF THE APPLICATION )
OF IDAHO POWER COMPANY FOR ) CASE NO. IPC-E-25-31
APPROVAL OR REJECTION OF AN )
ENERGY SALES AGREEMENT WITH ) IDAHO POWER COMPANY'S
FOSSIL GULCH WIND PARK, LLC FOR ) REPLY COMMENTS
THE SALE AND PURCHASE OF ELECTRIC )
ENERGY FROM THE FOSSIL GULCH )
WIND PARK. )
COMES NOW, Idaho Power Company ("Idaho Power" or "Company"), and,
pursuant to Idaho Public Utilities Commission's ("Commission") Rules of Procedure 201-
204, hereby respectfully submits the following Reply Comments in response to
Comments filed by Commission Staff ("Staff") on December 11, 2025.
IDAHO POWER COMPANY'S REPLY COMMENTS - 1

I. BACKGROUND
Idaho Power Company appreciates the Commission Staff's thorough review of the
Energy Sales Agreement ("ESA") with Fossil Gulch Wind Park, LLC ("Seller") and the
Interim Agreement. The Company offers these reply comments to clarify its position and
address specific recommendations.
II. REPLY COMMENTS
A. Recalculating the Avoided Cost of Energy and the Avoided Cost of
Capacity
Staff recommends recalculating both the avoided cost of energy and the avoided
cost of capacity using the Aurora model from the most recently filed 2025 Integrated
Resource Plan ("IRP") rather than the 2023 IRP (which remains the IRP most recently
acknowledged by the Commission) and incorporating the updated generation profile of
the Fossil Gulch Wind Park ("Facility"). Staff also supports using the Effective Load
Carrying Capability ("ELCU) methodology for capacity contribution. Staff's rationale is
that the latest IRP reflects current system conditions and resource changes, ensuring
accuracy and consistency with Commission precedent.
The Company conceptually agrees that using the most recently filed IRP is
preferable and is not opposed to this approach. However, Idaho Power has historically
relied on the most recently acknowledged IRP's Aurora model and inputs (other than the
gas price and load forecasts) for Incremental Cost Integrated Resource Plan ("ICIRP")
pricing. Idaho Power has discussed this in its application in several cases to update the
gas price or load forecasts, where it described its approach of updating all variables and
assumptions (i.e., including the Aurora model) in the ICIRP methodology every two years,
IDAHO POWER COMPANY'S REPLY COMMENTS -2

upon IRP acknowledgement, except for load and gas forecasts, which are updated
annually. See, e.g., Case No. IPC-E-15-25, Application at 1; Case No. IPC-E-16-22,
Application at 1-2; Case No. IPC-E-17-15, Application at 1-2; Case No. IPC-E-18-13,
Application at 1-2; Case No. IPC-E-19-31, Application at 1-2; IPC-E-20-35, Application at
1-2; Case No. IPC-E-21-15 at 1-3; Case No. IPC-E-22-26, Application at 2; Case No. IPC-
E-23-25, Application at 2; Case No. IPC-E-24-40, Application at 2; Case No. IPC-E-25-
33, Application at 2. The Commission issued its orders in each of those cases without
material discussion of the timing of the update to the ICIRP methodology Aurora model
and without raising concerns regarding the model being updated upon Commission
acknowledgement. See Order Nos. 33417; 33646; 33957; 34217; 34881; 35644; 36037;
and 36434. (The Commission has not yet issued an order in Case No. IPC-E-25-33, but
Staff did not raise this question in its comments in that case).
The Company recognizes that the direction on whether assumptions should be
updated upon IRP filings, versus IRP acknowledgement, has evolved for certain
assumptions over the past few years. For example, the capacity deficiency date
assumption historically had been updated as of the IRP filing, as directed in Order No.
32697, at 23. In 2017, the Commission revised the timing of the capacity deficiency date
update, requiring that each Idaho electric utility file its update capacity deficiency date
filing after the Commission has acknowledged its IRP report, rather than upon its IRP
filing..." Order No. 33917 at 4. In 2023, the Commission updated the direction again,
determining that the appropriate time for a utility to update its capacity deficiency date is
in fact after its IRP is filed, as opposed to after the date it is acknowledged. Order No.
35810 at 3.
IDAHO POWER COMPANY'S REPLY COMMENTS - 3

The Company does not disagree with Staff's recommendation to update the
ICIRP's method's Aurora model and inputs (other than the load and gas price forecast)
after the most recent IRP's filing (as opposed to acknowledgement). However, given the
long-standing historical practice of updating the model after the most recent IRP
acknowledgement, it requests the Commission provide explicit Commission direction on
this issue. If the Commission orders the use of the most recently filed IRP's Aurora model
in ICIRP methodology pricing, the Company will apply this direction to any current or
future ICIRP methodology pricing requests as well.
The Company is not opposed to Staff's other comments regarding the avoided cost
of energy and capacity, including the inclusion of resource changes with a high degree of
certainty, and updating the pricing based on the facility's updated generation profile. The
Company notes that updating the pricing on a continual basis based on new information,
even after indicative pricing may have been accepted by a project and during the
negotiation or finalization of the draft ESA, could create the potential for delay and pricing
disputes. For example, Staff recommends updating the pricing to reflect all resource
changes with high certainty as of September 26, 2025, the date the replacement ESA
had been executed by both parties. There may be logistical and contracting challenges
and potential delays associated with the pricing being subject to change even after a
contract has potentially been fully negotiated or partially executed. That being said, the
Company agrees these updates would potentially lead to more accurate pricing. If the
Commission adopts Staff's recommendation, the Company respectfully requests that the
Commission explicitly order this approach to avoid ambiguity and provide clarity for the
Company and developers.
IDAHO POWER COMPANY'S REPLY COMMENTS -4

B. Maximum Capacity Amount
Staff observes that the original ESA for this facility had a Maximum Capacity
Amount of 10 megawatts ("MW"), in contrast to the facility's nameplate capacity of 10.5
MW, and that the proposed Replacement ESA has aligned the Nameplate Capacity and
Maximum Capacity Amount at 10.5 MW. Staff recommends either reducing the Maximum
Capacity Amount to 10 MW or adopting a bifurcated rate structure for generation above
10 MW until the first capacity deficit date. Staff cites prior Commission orders allowing
both approaches when a facility's proposed capacity exceeds its original contract size.
Idaho Power is not opposed to Staff's recommendation to either reduce the
Maximum Capacity Amount to align with the prior agreement or adopt a bifurcated rate
structure for generation above 10 MW. If the Commission adopts Staff's recommendation
and directs the Company to use one or the other of those approaches, the Company will
work with the Facility to revise the agreement accordingly.
C. Contract Corrections
Staff recommends updating the ESA to correct the calculation description in Article
6.4.4, revise the Surplus Energy definition, remove redundant modification language in
Appendix B, and correct an error in Appendix E. Staff's reasoning is that these changes
are necessary for clarity and consistency with Commission precedent.
The Company agrees to address these items through an amendment and
compliance filing, contingent upon Seller agreement. The Company notes that typically
changes to the avoided cost pricing methodology and the way in which the avoided cost
is calculated would be done in a separate proceeding and not as part of a contract review
case. As stated, the Company will implement changes as directed by the Commission,
IDAHO POWER COMPANY'S REPLY COMMENTS - 5

however the Seller must also agree to such changes in a contract amendment, which the
Company will pursue and address as a subsequent compliance filing as recommended
by Staff. If the Seller does not agree, the ESA will terminate consistent with its terms.
III. CONCLUSION
The Company appreciates Staff's review and recommendations and remains
committed to implementing changes as approved by the Commission. The Company
respectfully requests that the Commission provide guidance regarding the use of the most
recently filed or most recently acknowledged IRP, and other items discussed herein, to
ensure consistency in future filings.
Respectfully submitted this 18t" day of December 2025.
LISA C. LANCE
Attorney for Idaho Power Company
IDAHO POWER COMPANY'S REPLY COMMENTS - 6

CERTIFICATE OF SERVICE
I HEREBY CERTIFY that on this 181" day of December 2025, 1 served a true and
correct copy of the within and foregoing IDAHO POWER COMPANY'S REPLY
COMMENTS upon the following named parties by the method indicated below, and
addressed to the following:
IPUC COMMISSION STAFF Hand Delivered
Adam Triplett U.S. Mail
Deputy Attorneys General Overnight Mail
Idaho Public Utilities Commission FAX
P.O. Box 83720 X Email — adam.triplett(cD_puc.idaho.gov
Boise, ID 83720-0074
Stacy Gust,
Regulatory Administrative Assistant
IDAHO POWER COMPANY'S REPLY COMMENTS - 7