20251021Reply Comments.pdf

_ ROCKY MOUNTAIN 1407 W. North Temple,Suite 330
POWER. Salt Lake City,UT 84116
A DIVISION OF PACIFICORP
RECEIVED
October 21, 2025 OCTOBER 21, 2025
IDAHO PUBLIC
VIA ELECTRONIC FILING UTILITIES COMMISSION
Commission Secretary
Idaho Public Utilities Commission
11331 W Chinden Blvd
Building 8 Suite 201A
Boise, Idaho, 83714
RE: CASE NO. PAC-E-25-12 - IN THE MATTER OF PACIFICORP'S APPLICATION
FOR ACKNOWLEDGEMENT OF THE 2025 INTEGRATED RESOURCE PLAN
Dear Commission Secretary:
Pursuant to Commission Order No. 36683 -Notice of Modified Procedure, issued July 22, 2025,
in the above referenced matter, PacifiCorp submits reply comments to written comments filed by
Commission Staff.
Informal inquiries may be directed to Mark Alder, Idaho Regulatory Affairs Manager, at
[phone].
Sincerely,
A 9�zal',D
Joelle Steward
Senior Vice President, Regulation
Enclosures

Joe Dallas (ISB# 10330)
825 NE Multnomah, Suite 2000
Portland, OR 97232
Telephone: [phone]
Email: joseph.dallas(&,pacificorp.com
Attorney for Rocky Mountain Power
BEFORE THE IDAHO PUBLIC UTILITIES COMMISSION
IN THE MATTER OF PACIFICORP'S ) CASE NO. PAC-E-25-12
APPLICATION FOR ACKNOWLEDGEMENT )
OF THE 2025 INTEGRATED RESOURCE ) REPLY COMMENTS OF
PLAN ) ROCKY MOUNTAIN POWER
In accordance with Rule 202.01(d) of the Rules of Procedure of the Idaho Public Utilities
Commission ("Commission") and the Commission's July 22, 2025 Order No. 36683 —Notice of
Modified Procedure, PacifiCorp d/b/a Rocky Mountain Power ("PacifiCorp" or the "Company"),
by and through its counsel, provides these Reply Comments to the comments received by the
Commission from the Commission's Staff("Staff').
I. PROCEDURAL BACKGROUND
1. On March 31, 2025, PacifiCorp filed its 2025 Integrated Resource Plan ("2023
IRP") with the Commission pursuant to the Commission's Order No. 22299, Case No. U-1500-
165, dated January 1989 ("Order No. 22299") that requires utilities to file bi-annual Integrated
Resource Plans ("IRPs").
2. On June 3, 2025, the Commission issued Order No. 36620 -Notice of Application
and Notice of Intervention. Interested parties were given 21 days to intervene in the case. On June
25, 2023, the Commission issued a Notice of Parties listing the Company and Staff as parties to
the case.
1

3. On July 22, 2025, the Commission issued Order No. 36683 - Notice of Modified
Procedure, which informed the parties that the case would be processed under the Rules of
Procedure 201 through 204 and established a procedural schedule for interested parties to file
comments by October 7,2025,with the Company's reply comments due on October 21, 2025. On
October 7, 2025, Staff filed comments on the Company's 2025 IRP.
II. COMMISSION IRP STANDARDS
4. The IRP is a 20-yearl long-term resource plan intended to identify the least-cost,
least risk portfolio of generation and transmission resources needed to meet the Company's
obligation to serve. In Order No. 22299, the Commission required each electric utility party to
submit a report of the status of its resource planning and established the standard for IRPs.2 The
reporting requirements the Commission established are:
(1) Discuss any flexibilities and analyses considered during comprehensive
resource planning, such as:
a. Examination of load forecast uncertainties;
b. Effects of known or potential changes to existing resources;
C. Consideration of demand and supply side resource options; and
d. Contingencies for upgrading, optioning, and acquiring resources at
optimum times(considering cost,availability,lead time,reliability,
risk, etc.) as future events unfold.
(2) Address Existing Resource Stack, Load Forecast, and Additional
Resource Menu.3
' The 2025 IRP used a 21-year modeling horizon due to a requirement from Washington to provide modeling results
for 2045.Past and future IRPs used a 20-year modeling horizon.
2 In the Matter of the Investigation by the Idaho Public Utilities Commission into Idaho Electric Utility Conservation
Standards and Practices. Order No.222299. (January 27,1989).
3 Id at 7.
2

5. In addition to complying with Order No. 22299,there are guidelines from previous
IRP orders that are still relevant for PacifiCorp and its 2025 IRP. With the 2021 IRP Order No.
35514, Case No. PAC-E-21-19, dated August 30, 2022 ("2021 IRP Order") the Commission
directed to Company to:
• Explore an approach allowing for the selection of natural gas resources
in a portfolio while also providing an adjustment to the cost based on the
expected cost risk of becoming a stranded asset; and
• Better assess the risks of technology viability and potential delays
inherent with the Natrium nuclear plant implementation and plan for
contingencies.
6. The 2023 IRP Order No. 35977, Case No. PAC-E-23-10, dated October 31, 2023
("2023 IRP Order") established an expectation for the 2025 IRP to include a discussion of the
impacts of Western Resource Adequacy Program("WRAP")compliance and appropriate planning
margin and resource requirements. The Company has the standards and requirements laid out in
both the 2021 IRP Order and the 2023 IRP Order. For ease of reference, Appendix B of the 2025
IRP lists the requirements included in the 2021 and 2023 IRP Orders and provides a reference to
where those requirements were met.4
7. To be acknowledged, the 2025 IRP must address the requirements of Order No.
22299,the 2021 IRP Order, and the 2023 IRP Order. Because the Company's 2025 IRP meets the
requirements of these orders, the Commission should acknowledge the Company's 2025 IRP.
III. INTRODUCTION
8. The 2025 IRP was developed after substantial stakeholder input. PacifiCorp began
a series of broader-topic general public-input meetings starting in January 2024, which addressed
a range of subjects describing PacifiCorp's modeling methodology, inputs, and assumptions for
4 2025 IRP,Appendix B—IRP Regulatory Compliance at 30.
3

the 2025 IRP. Agenda topics included, but were not limited to, resource cost-and-performance
assumptions, model function and overview, load forecast, price-policy assumptions, market price
assumptions,jurisdictional clean energy obligations and transmission options. In all, PacifiCorp
held nine public-input meetings. Public-input meeting materials, supporting studies, and
stakeholder feedback forms can be found on PacifiCorp's IRP webpage.5
9. The resulting 2025 IRP and action plan ensures that PacifiCorp will provide
adequate and reliable electricity supply to its customers at a reasonable cost. PacifiCorp's selection
of the 2025 IRP preferred portfolio is supported by detailed data analysis under the following
commitments steps: (1) Prioritizing Savings and Value for Customers, (2) Expanding Clean
Power; (3) Building Storage Capacity; and (4) Investing in Transmission.' Each of these steps in
the 2025 IRP development process are presented in greater detail in the Company's filing,
including the supporting work papers that present the underlying data for each of the portfolios
analyzed by PacifiCorp.
10. In these Reply Comments, PacifiCorp describes how the 2025 IRP and the
associated action plan comply with all Commission requirements and responds to comments made
by Staff. Because the 2025 IRP meets all Commission guidelines, the Company respectfully
requests that the Commission acknowledge the 2025 IRP.
5 See https://www.pacificorp.com/energy/integrated-resource-plan.html; See also the 2025 IRP Volume II,Appendix
C—Public-Input Process for more detail.
6 2025 IRP, Chapter 10 —Action Plan. Presentation of PacifiCorp's 2025 IRP action plan linking the company's
preferred portfolio with specific implementation actions, including an accompanying resource acquisition path
analysis and discussion of resource procurement risks.
2025 IRP,Chapter 1—Executive Summary at 2.
4

IV. REPLY TO STAFF'S COMMENTS
11. Staff recommends the Commission acknowledge the Company's 2025 IRP based
on their review of the 2025 IRP and participation in stakeholder meetings. Staff recognizes that
the 2025 IRP met the requirements in Order No. 22299.
12. While Staff recommends acknowledgment of the plan,they raise several key points.
Staff proposes meeting with the Company to develop an Idaho-specific portfolio and to address
the need to balance resource adequacy requirements with the risk of overbuilding. Staff also has
several modeling recommendations including how price-policy scenarios are used,the application
of"end effects" to all portfolios, and an additional verification step to confirm that the selected
preferred portfolio ("PP") meets the defined loss of load expectation ("LOLE") target. Finally,
Staff has additional recommended requirements such as providing a Boardman-to-Hemmingway
(`1321­1") re-evaluation study and additional review of its hedging practices to reduce exposure to
natural gas volatility. The Company will address each of these items in these reply comments.
A. Preferred Portfolio (PP) Selection and Evaluation Methodology
i. Justification of PP selection
13. In their comments, Staff notes that some variant portfolios perform better than the
Integrated Base MN portfolio across other price-policy scenarios and requests further justification
of the Company's selection of the MN portfolio as the preferred portfolio.'
14. PacifiCorp selected the Integrated Base MN portfolio based on its performance
under the MN price-policy scenario after consideration of the stochastic risk adjustment and end
effects. The MN price-policy scenario is the expected price-policy scenario and therefore portfolio
cost under MN dispatch is more meaningful than costs under other price-policy scenarios.
s Staff Comments p.7-8.
5

Additionally, stochastic analysis and end effects were only completed for the MN price-policy
scenario, so results under MN are more robust than results under other price-policy scenarios.
For stochastic analysis, PacifiCorp developed 18 years of actual data, including thermal outages,
load, renewable shapes, and market and gas prices. PacifiCorp then dispatched each variant
portfolio under all 18 of these historical conditions, stress-testing the ability of each portfolio to
cost-effectively serve load under extreme conditions. The variable costs from these model runs
were then used to calculate the stochastic risk adjustment.As a result, the risk-adjusted PVRR of
each portfolio under MN incorporates the risk that conditions may vary significantly from the
expected case.
H. End Effects
15. Staff recommends that the Commission direct PacifiCorp to apply"end effects" to
all price-policy scenarios, not just MN, in future IRPs.9 PacifiCorp is not opposed to this
recommendation, while still emphasizing that there are tradeoffs in developing IRPs, and
increasing the scope of a particular analysis will require diminishing the scope of a different
analysis.
iii. FOTs
16. Staff believes that not counting front office transactions (FOTs) towards WRAP
compliance in the integrated PP could result in overbuilding and recommends the Company be
directed to meet with Staff to explore how to balance meeting the WRAP compliance while
avoiding overbuilding resources.l° In the 2025 IRP, PacifiCorp did not evaluate the cost-
effectiveness of FOTs relative to proxy resource options. While FOTs may be able to fill future
resource needs, it has traditionally been agreed by all parties that reliance on FOTs is risky.
9 Id.
10 Staff Comments p.14-15.
6

PacifiCorp would be open to including a limited quantity of market purchases as an option
comparable to other proxy resource options available for selection by the model and eligible to
contribute to resource adequacy in the 2027 IRP. PacifiCorp looks forward to meeting with Idaho
Staff and discussing how to balance the costs and risks of building new resources and relying on
FOTs.
iv. LOLE Target and Additional Verification
17. Staff believes the Company should include an additional verification step to
confirm the PP meets the LOLE target and clarify how the target of 2.4 event hours per year is
achieved." The chart previously labeled as Figure K.2 in the 2025 IRP 12 is reproduced below as
Figure 1 and shows all loss-of-load events for the 2025 IRP preferred portfolio. There is a total of
221 loss-of-load hours across the 18 stochastic 21-year runs, which is 0.58 event hours per year,
which is well within the 2.4 event hours target. PacifiCorp does not oppose Staff's
recommendation that future IRPs include more reporting of loss-of-load events.
11 Staff Comments p.16.
12 See Volume II,page 181.
7

Figure 1
10 •
12 9 • Each triangle
0 8 represents one
o loss of load event
o 7 • •
4.
a
6 • Y •
Ca 5 • • •
c
4 • • A►
W
3 • Y • AL0
`0 2 ♦ • • W► • IYY
c1 AM& AM" � AM •v
0
0
Summer Winter Summer Winter Summer Winter Summer Winter
2025- 2025- 2028- 2023- 2037- 2037- 2042- 2042-
2027 2027 2031 2031 2041 2041 2045 2045
B. Fuel Supply and Price Volatility
i. Coal-to-Gas Conversion and Volatility Risk
18. Staff is concerned that coal-to-gas conversions introduce price volatility risk and
recommends the Company review hedging practices to mitigate exposure.13 PacifiCorp has
scheduled a workshop with Staff on November 6, 2025 to discuss its hedging strategy. The
Company reviews the Energy Risk Management Policy("Policy") for any required updates on an
annual basis.Additionally, the Company's Policy defines minimum and maximum limits in order
to prevent under-hedging and over-hedging. Those minimum and maximum limits are expressed
as a percentage of forecasted requirements, which means that when unit conversions occur, the
Company's requirements forecast will increase, and the Company's hedging requirements will
13 Staff Comments p.9-10.
8

follow. This feature of the policy should help the Company to maintain prudent risk management
of fuel costs when unit conversions occur.
19. The risks of fuel price volatility are also analyzed in the IRP. Stochastic analysis
ensures the consideration of natural gas price volatility, directly impacting the evaluation of
relative risk among competing portfolios. PacifiCorp's price-policy analysis also considers
alternative scenarios, such as the high natural gas, high CO2 price-policy scenario. Pages 197-199
in Volume 1, Chapter 8 of the 2025 IRP include more detail on all price-policy scenarios included
in the IRP.
ii. Changes in Federal Policy
20. Staff believes that elimination of certain federal tax credits may invalidate parts of
the IRP and requests an incremental analysis reflecting recent policy changes.14 PacifiCorp's
integrated resource plan is a snapshot in time, that is updated annually. In other words, modeling
requires that assumptions to locked down by a fixed date. In the case of the 2025 IRP, assumptions
were locked down in September 2024 to allow for time for data input,model runs, and publication
of the IRP update by January 2025. Accordingly, given the mechanics and realities of modeling,
the 2025 IRP did not reflect the changes in federal policy of the new federal administration.
21. PacifiCorp is not able to predict the outcome of federal legislation. PacifiCorp's
2025 IRP was filed on March, 31, 2025, more than three full months before H.R. 1 became law.
At the time PacifiCorp filed its 2025 IRP, the outcome of H.R. 1 was highly uncertain.
Furthermore,in order to complete modeling and analysis for the 2025 IRP,PacifiCorp locked down
the majority of input data and assumptions impacting modeling in the 2025 IRP in September
2024. For these reasons it was reasonable for the Company to model the IRA/IIJA federal tax
14 Staff Comments at p.4 and p.13.
9

credits for new renewable and storage resources in its 2025 IRR PacifiCorp agrees that analysis
representing H.R. 1 tax credits for new renewable and storage resources is necessary, and will
include incremental analysis representing these changes in federal tax credits is the 2025 IRP
Update.
C. Transmission Projects and Load Forecast Assumptions
i. Large-customer Load System Impacts
22. Staff is concerned about the removal of large-customer loads from the load forecast,
including the treatment of reserves,potential system impacts, and allocation of transmission costs
to Idaho customers.15 PacifiCorp includes large new load in its planning but does not include large
new load in its system optimization of proxy resources for the purposes of the IRR This is
specifically to protect PacifiCorp's other customers,but also because the associated resources will
not be selected as a part of the IRP-to-RFP process and should not be optimized on the same proxy
basis. Special contracts or tariffs will determine the matching of large meter load and resources,
and the IRP does not model special contracts as options,but rather as they become committed and
later executed. PacifiCorp also notes that in its 2023 IRP certain stakeholders criticized the
Company for including large load in the IRP, calling such load speculative and alleging that such
treatment could result in overbuild. PacifiCorp is open to evaluating the impacts of large loads in
the context of a sensitivity in the 2025 IRP Update.
ii. B2H re-evaluation study
23. Staff recommends the Company provide its re-evaluation study regarding 132H and
is concerned that the B2H CPCN may be affected. PacifiCorp included most of the benefits
associated with B2H in the 2025 IRP preferred portfolio, including the incremental West-to-East
15 Staff Comments p.10-13.
10

transfer capability and other regional transmission benefits, and PacifiCorp continues to move
forward with Idaho Power in the construction of B2H. PacifiCorp does not presently have
transmission rights to move westbound transfers across B2H to other existing customer loads on
its system, and PacifiCorp does not know when BPA will restart consideration of long-term
transmission requests or changes in the future.At this time, it is unknown when BPA will reinitiate
its study process, what types of transmission planning reforms it might implement when it does
reinstate its study process,and what the study results for PacifiCorp's redirect requests might show.
Consequently, it is unknown when or if the redirect requests might be granted, when the redirect
requests might become effective, and how much it might cost for upgrades, if any,needed to grant
the redirect requests.
24. As a result, B2H could not serve any of the existing West side load that was
included in the development of the 2025 IRP preferred portfolio.While the B211 project would not
serve existing load in the 2025 IRP analysis, there is new retail load expected to enter the system
which 13211 can serve, preserving its usefulness. Therefore, despite the current BPA transmission
restrictions,PacifiCorp stands by the modeling assumptions included in its application in Case No.
PAC-E-23-0116. This is because an IRP is designed to identify least-cost, least-risk portfolios. A
plan that assumes 13211 will obtain the redirect directs when BPA has suspended its study process
is notably high-risk for the near term. However, if any clarity given from BPA in time for the 2025
IRP Update,will be reflected in that Update.The Company also plans to run additional sensitivities
for its upcoming 2025 IRP Update, anticipated to be distributed on March 31, 2026, and subject to
stakeholder discussion in its current IRP public input meeting series.
16 In the Matter of the Application of Rocky Mountain Power for a Certificate of Public Convenience and Necessity
Authorizing Construction of the Boardman-to-Hemmingway 500-kv Transmission Line Project. Case No.PAC-E-23-
01 (Filed January 27,2023).
11

D. Advanced Technologies and Resource Timing
25. Staff recommends the Company determine the actual timing of Natrium to avoid
short-term resource commitments that could increase long-term costs and risks.Pending regulatory
approvals," PacifiCorp has reached a commercial arrangement with TerraPower related to the
Natrium demonstration project that protects customers from first-of-a-kind technology risks and
supports the ability to address growing demand for clean, baseload power. The Natrium
demonstration project has been named Kemmerer Power Station Unit 1 ("KU1") by TerraPower
and is currently in the design and licensing phase. The Construction Permit Application was
submitted to the US Nuclear Regulatory Commission("US NRC") in March, 2024. The US NRC
has streamlined their application review schedule and now anticipates the final safety evaluation
for the Preliminary Safety Analysis Report and final environmental impact statement to be
complete by December, 2025, and the Construction Permit Application to be approved in early
2026. This approval will allow the beginning of construction of the Nuclear Island. On September
9, 2024,TerraPower submitted an exemption request to the US NRC related to construction of the
Energy Island. The US NRC issued the exemption on May 7, 2025, allowing construction of the
Energy Island to proceed prior to issuance of the Construction Permit. Construction on the Energy
Island is anticipated to begin in 2025. Construction of the Sodium Test&Fill Facility is underway
which includes the completion of the concrete foundation. TerraPower began construction of the
Kemmerer Training Center in August 2025.
17 In Idaho,the Company has recently filed an application for the Natrium project.For more detail on this project see
In the Matter of the Application of Rocky Mountain Power for a Waiver of the Solicitation Requirements Proposed in
Case No. GNR-E-25-01. Case No.PAC-E-25-10(Filed October 20,2025).
12

26. Project status as tracked by the Nuclear Regulatory Commission ("NRC") can be
found on the NRC's website (https://www.nrc.gov/reactors/new-reactors/advanced/who-were-
working-with/applicant-projects/terrapower.html).PaciflCorp is willing to provide annual or semi-
annual reports regarding the status of the Natrium (Kemmerer Unit 1, or KU 1) nuclear project
beginning January 2026 if the Public Utility Commission of Idaho desires.
iii. Idaho-Specific Portfolio Development
27. Staff recommends the Commission direct the Company to meet with Staff to
explore developing an Idaho-specific portfolio before the next IRP. The Company has no
objections to having this discussion and looks forward to meeting with Staff to explore this further.
V. CONCLUSION
28. PacifiCorp's 2025 IRP complies with the Commission standards and requirements.
The 2025 IRP includes robust and extensive portfolio modeling under a wide-range of price-policy
scenarios and other prudent planning assumptions discussed with, and reflective of, stakeholder
input that ultimately results in the selection of a least-cost, least-risk preferred portfolio. The 2025
IRP also includes an action plan that is consistent with the long-term public interest. The
Company's 2025 IRP satisfies all the requirements in Order No. 22299 and the 2021 and 2023 IRP
orders; therefore, the Company respectfully requests that the Commission acknowledge the
Company's 2025 IRP.
13

DATED this 21 st day of October 2025.
Respectfully submitted,
ROCKY MOUNTAIN POWER
Joe Dallas (ISB# 10330)
825 NE Multnomah, Suite 2000
Portland, OR 97232
Telephone: [phone]
Email:joseph.dallasgpacificorp.com
Attorney for Rocky Mountain Power
14