20260403Application - Redacted.pdf

"4%6h-0IQAHO POWER.
LISA C. LANCE
Corporate Counsel
l lance(a)-idahopower.com
April 3, 2026
Commission Secretary
Idaho Public Utilities Commission
11331 W. Chinden Boulevard
Building 8, Suite 201-A
Boise, Idaho 83714
Re: Case Nos. IPC-E-26-09 & PAC-E-26-06
Application of Idaho Power Company and PacifiCorp D/B/A Rocky Mountain
Power for Certificates of Public Convenience and Necessity for Segment E-8
of the Gateway West 500-kV Transmission Line.
Dear Commission Secretary:
Attached for electronic filing, please find Idaho Power Company and PacifiCorp's
Application in the above-entitled matter. In addition, please find attached the Direct
Testimony of Jared Ellsworth, Rick Vail, and Lindsay Barretto filed in support of the
Application. A Word version of the testimonies will also be sent in a separate email for the
convenience of the Reporter.
Also attached is the Protective Agreement. The confidential documents will be
provided in a separate email to the parties who sign the Protective Agreement.
If you have any questions about the attached documents, please do not hesitate
to contact me.
Sincerely,
D� VG Go�
Lisa C. Lance
LCL:sg
Attachments
1221 W. Idaho St(83702)
P.O. Box 70
Boise, ID 83707

CERTIFICATE OF ATTORNEY
ASSERTION THAT INFORMATION CONTAINED IN AN IDAHO PUBLIC UTILITIES
COMMISSION FILING IS PROTECTED FROM PUBLIC INSPECTION
CASE NOS. IPC-E-26-09 & PAC-E-26-06
Application of Idaho Power Company and PacifiCorp D/B/A Rocky Mountain
Power for Certificates of Public Convenience and Necessity for Segment E-8 of
the Gateway West 500-kV Transmission Line
The undersigned attorney, in accordance with Commission Rules of Procedure 67,
believes that the Application and the Direct Testimony of Lindsay Barretto and Exhibit No.
5 to the Direct Testimony of Lindsay Barretto dated April 3, 2026, contain information that
Idaho Power Company and a third party claims are trade secrets, business records of a
private enterprise require by law to be submitted to or inspected by a public agency,
and/or public records exempt from disclosure by state or federal law (material nonpublic
information under U.S. Securities and Exchange Commission Regulation FD) as
described in Idaho Code§ 74-101, et seq., and/or§48-801, et seq. As such, it is protected
from public disclosure and exempt from public inspection, examination, or copying.
DATED this 3rd day of April 2026.
/.,. G/�
Lisa C. Lance
Attorney for Idaho Power Company

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]
Ilance(o)_idahopower.com
Attorney for Idaho Power Company
JOSEPH DALLAS (ISB No. 10330)
Assistant General Counsel
PacifiCorp
825 NE Multnomah Street, Suite 2000
Portland, Oregon 97232
Telephone: [phone].
Joseph.Dallas(a),pacificorp.com
Attorney for PacifiCorp
BEFORE THE IDAHO PUBLIC UTILITIES COMMISSION
IN THE MATTER OF THE APPLICATION )
OF IDAHO POWER COMPANY AND ) CASE NO. IPC-E-26-09
PACIFICORP D/B/A ROCKY MOUNTAIN )
POWER FOR CERTIFICATES OF PUBLIC ) CASE NO. PAC-E-26-06
CONVENIENCE AND NECESSITY FOR )
SEGMENT E-8 OF THE GATEWAY WEST ) APPLICATION
500-KV TRANSMISSION LINE. )
Idaho Power Company ("Idaho Power" or "Company") and PacifiCorp d/b/a Rocky
Mountain Power (collectively referred to as "PacifiCorp") (together, the "Parties" or "each
Party"), in accordance with Idaho Code §§ 61-501 , 61-502, 61-503, 61-508, 61-526; as
well as Rule of Procedure ("RP") 52, 112 and 201 hereby respectfully makes application
APPLICATION - 1

to the Idaho Public Utilities Commission ("Commission") for an order granting Idaho
Power and PacifiCorp each a Certificate of Public Convenience and Necessity ("CPCN")
for Segment E-8 of the Gateway West 500-kilovolt ("kV") line ("Segment E-8"). Segment
E-8 of Gateway West will create up to 2,000 megawatts ("MW") of additional transmission
capacity, allowing the Company to maintain adequate system reliability and providing the
ability to interconnect new generation resources across Idaho. In this proceeding, the
Parties request that the Commission find Segment E-8 of Gateway West to be in the
public interest and grant each Party a CPCN allowing for the commencement of
construction of Segment E-8. The Parties respectfully request the Commission issue the
CPCNs no later than October 31, 2026, prior to the Parties entering into any contracts
associated with construction of Segment E-8.
Accompanying this Application are three sets of testimony. The Direct Testimony
of Idaho Power's Witness, Jared L. Ellsworth begins with an overview of the Gateway
West transmission project, describing Segment E-8 of Gateway West which is jointly
owned by the Parties. Next, he discusses the identification of the Gateway West project
in the Regional Transmission Plans and the inclusion of Gateway West as part of Idaho
Power's Integrated Resource Planning ("IRP") process, detailing the Gateway West
analysis performed as part of the 2023 IRP, and subsequently refined in the 2025 IRP,
as a necessary transmission investment to cost-effectively enable incremental resource
additions. Finally, Mr. Ellsworth describes the benefits associated with the addition of
Segment E-8, including the bolstering of the transmission capability to support system
load growth and the improved ability to interconnect new generation resources.
APPLICATION - 2

Next, the Direct Testimony of PacifiCorp's Witness, Mr. Rick A. Vail discusses
PacifiCorp's current ownership of Segment E-8 in accordance with the structure of the
Gateway West Joint Permit Funding Agreement, including the associated amendments.
In addition, he describes PacifiCorp's need for Segment E-8 to meet its customers' short-
and long-term energy demand and for strengthening of the overall reliability of the existing
transmission system. Lastly, Mr. Vail details the pre-construction activities undertaken to
obtain necessary federal, state, and local permits and other project development work.
Finally, the Direct Testimony of Idaho Power's Witness, Ms. Lindsay Barretto
begins with a summary of Idaho Power's involvement in Segment E-8 pre-construction
activities performed by PacifiCorp and discussed in the Direct Testimony of Mr. Rick Vail.
Next, she provides a description of the transmission line design of Segment E-8 and the
standards and guidelines for which it will be constructed and operated. Finally, Ms.
Barretto describes the planned Segment E-8 construction activities and discusses the
total estimated costs associated with the project.
I. CORPORATE STATUS
1. Idaho Power is a corporation incorporated under the laws of the state of
Idaho. Idaho Power is engaged in the business of generating, purchasing, transmitting,
and distributing electric energy and providing retail electric service in the states of Idaho
and Oregon. Idaho Power's principal offices are situated in Boise, Idaho, and its address
is 1221 West Idaho Street, Boise, Idaho 83702. Copies of Idaho Power's Articles of
Incorporation and Certificates of Convenience and Necessity are on file with the
Commission. Idaho Code § 61-528.
2. PacifiCorp provides retail electric service under the name Rocky Mountain
Power in the states of Wyoming, Utah, and Idaho, and under the name Pacific Power in
APPLICATION - 3

the states of Oregon, Washington, and California. Rocky Mountain Power is a public utility
in the state of Idaho subject to the Commission's jurisdiction with respect to its prices and
terms of electric service to retail customers in Idaho pursuant to Idaho Code § 61-129.
Rocky Mountain Power is authorized to do business in the state of Idaho providing retail
electric service to approximately 88,000 customers in the state. Copies of PacifiCorp's
Articles of Incorporation and Certificates of Convenience and Necessity are on file with
the Commission. Idaho Code § 61-528.
II. BACKGROUND
3. PacifiCorp's Gateway Transmission Expansion Program, a plan to build
over 2,300 miles of new high-voltage transmission lines, primarily in Wyoming, Utah,
Idaho and Oregon, includes transmission lines in the Gateway Central, Gateway West,
Gateway South, and West of Hemingway regions, with routes within the regions identified
as Segments A through H. The Gateway West project includes the addition of
approximately 1,000 miles of transmission lines identified as Segments D and E and will
run from the planned Windstar substation near Glenrock, Wyoming, to the Hemingway
substation near Melba, Idaho, when completed. Segments D and E are further
categorized into Segments 1 through 10. Idaho Power has a joint ownership interest with
PacifiCorp in Segments 6, 8, 9, and 10. However, as part of this proceeding, the Parties
are each requesting a CPCN for Segment E-8 only.
4. Segment E-8 is an approximately 133 mile 500-kV line that will run from the
Midpoint substation, near Jerome, Idaho, to the Hemingway Substation, near Melba,
Idaho. The Segment E-8 line will connect to Idaho Power's proposed 500-kV Mayfield
substation, located near Mayfield, Idaho, resulting in two sections of the Segment E-8
line, the approximately 40-mile Hemingway to Mayfield 500-kV line and the approximately
APPLICATION - 4

90-mile Mayfield to Midpoint 500-kV line. A map of Segment E-8 within the Gateway West
transmission project is included as Exhibit No. 2 to the Direct Testimony of Mr. Jared
Ellsworth.
5. The addition of Segment E-8 will create approximately 2,000 MW of
additional needed transmission capacity on Idaho Power's Midpoint West and Boise East
transmission paths, which are currently fully subscribed and utilized. The increased
capacity on these paths will support bidirectional transfers between the Magic and
Treasure Valleys. The project will support delivery of energy to the Treasure Valley from
planned new resource interconnections in the Mountain Home and Magic Valley areas.
As new resources are added near the Treasure Valley, Segment E-8 will also support
economic transfers of west-to-east energy to serve growth in the Magic Valley area.
Currently, Idaho Power will have 99 percent ownership interest in the capacity of Segment
E-8 and PacifiCorp will have the remaining one percent ownership interest.
III. MODELING OF GATEWAY WEST
6. Gateway West was first identified through the regional transmission
planning process conducted in 2007, along with the 2008-2009 biennial planning process.
This process involves the evaluation of the region's transmission needs, in the 10-year
planning horizon. By identifying potential resource areas and load center growth, the
required transmission capacity expansions to safely and reliably provide service to
customers are identified. Components of the Gateway West project have been
consistently selected in each biennial regional transmission plan since. Gateway West
was identified in the Regional Transmission Plan to mitigate forecasted thermal overload
violations primarily identified for east-to-west transfer hours across Southern Idaho.
APPLICATION - 5

Segment E-8 specifically was selected to create more Midpoint West capacity and
determined to be more cost-effective or efficient to meet the needs of southern Idaho
within the NorthernGrid footprint.
7. Following identification in the regional transmission plans, Gateway West
was first considered as part of Idaho Power's 2009 IRP. In the latter half of the planning
horizon of the 2009 IRP, 2020-2029, the Gateway West project was included in every
portfolio because then-current constraints would require the addition of new transmission
capacity for resources to be added in southern Idaho, east of the Treasure Valley load
center. Ultimately, beginning with the 2015 IRP, Idaho Power began modeling Segment
E-8 separately from other segments of Gateway West. The results indicated that the
Gateway West segments in which Idaho Power had ownership remained a key future
resource, promoting continued grid reliability in a time of expanding energy resources.
Idaho Power continued modeling the segments of the Gateway West project for which it
had an ownership interest as part of subsequent IRPs until the 2023 IRP when a more
robust analysis was performed.
8. Unlike the Boardman-to-Hemingway ('KH") or the Southwest Intertie
Project ("SWIP")-North transmission lines, the Gateway West project does not individually
provide access to a liquid market hub, additional transmission is needed to do so, and
therefore does not act as a stand-alone resource. However, without Gateway West, the
number of incremental resources that can be added to the Idaho Power's system is
constrained. As such, as part of the 2023 IRP, the Gateway West project was modeled
as an enabling project to allow the incremental resource additions to be interconnected
on the Idaho Power transmission system east of the Treasure Valley.
APPLICATION - 6

9. Idaho Power modeled its ownership interest at the time and allowed the
selection of up to 1,725 MW of incremental variable resources to be interconnected to the
existing grid, between 2024 and 2028, prior to the need to construct the first phase of
Gateway West. Beyond 1 ,725 MW of incremental variable resources, the analysis
modeled each subsequent Gateway West addition as enabling 1,000 MW of incremental
variable resources onto the system. The purpose of the Gateway West phase modeling
was to test the cost effectiveness of the various Gateway West phases, allowing Idaho
Power to develop differing portfolios with the additions of Gateway West. The results
indicated a resource portfolio without any phases of the Gateway West project would be
$580 million higher on a net present value basis. As a result, Idaho Power's 2023 IRP
Near-Term Action Plan for the 2024-2028 time period included bringing the first phase of
Gateway West, Segments E-8 and E-10 and the construction of Idaho Power's Mayfield
substation, online.
10. As part of the 2025 IRP, Idaho Power again modeled the Gateway West
project however, when developing the portfolios, it had become clear that developing a
portfolio without Segment E-8, even at Idaho Power's recently-increased capacity level,
was not a possibility. With the inclusion of 2,965 MW of new gas, wind, and solar
generation resource additions in the 2025 IRP portfolios, and load growth over the 20-
year planning horizon being focused heavily on the Treasure Valley area, absent the
addition of Segment E-8, new resources must be sited within the Treasure Valley area
which has proven to be challenging. In addition, the limited capacity available between
the Magic Valley and Treasure Valley area necessitates a transmission capacity upgrade
east of the Treasure Valley to support the increased generation. Therefore, the addition
APPLICATION - 7

of Segment E-8, assuming the Company's 99 percent ownership, or a 1,980 MW of
incremental capacity, was modeled as a baseline assumption to enable the incremental
resource additions. Gateway West Segment E-8 was a key component of Idaho Power's
2025 IRP Preferred Portfolio.
IV. SEGMENT E-8 PRE-CONSTRUCTION ACTIVITIES
11. Pre-construction activities have occurred to support the Segment E-8
project since 2018, when the right-of-way was granted by the Bureau of Land
Management ("BLM"). Following the initial introduction to federal and state agencies, in
2023 the project was introduced to local agencies, and the bulk of pre-construction
activities began to move forward. Pre-construction activities include environmental,
cultural and paleontological surveys, obtaining the necessary easements, and
engineering design. In response to requirements set forth in Section 7 of the Endangered
Species Act (ESA), Section 106 of the National Historic Preservation Act (NHPA), the
Paleontological Resources Preservation Act, and Section 404 of the Clean Water Act
(CWA), pedestrian field surveys have been conducted for: (1) special-status species of
plants and wildlife, (2) cultural resources, (3) paleontological resources, and (4) areas that
were identified as having large wetlands or wetland complexes and most stream/wash
crossings. The intent of the surveys was to derive recommendations to avoid or mitigate
impacts on environmental resources, address site-specific mitigation, and to develop the
mitigation required for the issuance of the BLM right-of-way.
12. Segment E-8 will be located on federal land managed by the BLM and the
Bureau of Reclamation, state lands managed by the Idaho Department of Lands, and
private lands. Therefore, new permanent and temporary land rights are required for the
APPLICATION - 8

transmission line facilities, primarily for the transmission line corridor, access roads, and
work areas. Pre-construction activities included the work to obtain a permanent 250-foot-
wide right-of-way for Segment E-8 and the associated access roads across federal lands.
The Parties continue to work with the Idaho Department of State Lands to acquire
appropriate easements across state lands for permanent facilities prior to construction,
as well as with private landowners to obtain the necessary easements. Finally, the
existing utilities that may be impacted by Segment E-8, have been identified and the
Parties are working with the owners to obtain necessary approvals.
13. With respect to permitting activities, the Parties have held eight public open
house events and three neighborhood meetings to date, which were held both in-person
at various locations near the Segment E-8 route as well as virtual for those unable to
attend on site. Stakeholder briefings have been held with Ada County, Canyon County,
Elmore County, Gooding County, Jerome County, Lincoln County, and Owyhee County,
as well as with the Idaho Office of the Lieutenant Governor, the Magic Valley
Congressional District, and the Boise Congressional District.
14. The Gateway West Segment E-8 transmission project is progressing
through required permitting and right-of-way activities. In addition to the public open
houses and neighborhood meetings that have been held, additional neighborhood
meetings are planned in accordance with conditional use permit requirements. The
project team continues to work with stakeholders and coordinate efforts as the team
addresses environmental, land use, agricultural, historical, and public safety
considerations.
APPLICATION - 9

V. SEGMENT E-8 DESIGN AND CONSTRUCTION
15. In addition to the construction of Segment E-8, expansion of the Midpoint
substation and modification of the Hemingway substation will be required to
accommodate the project. One communication regeneration site will also be constructed.
Segment E-8 is designed to withstand a wide range of physical conditions and extreme
events. Because transmission lines are so vital to the electrical grid, design standards are
stringent. Segment E-8 of Gateway West will adhere to, and where appropriate, exceed,
the required codes or standards observed for high voltage transmission line design. Both
Idaho Power and PacifiCorp have developed transmission line standards in accordance
with the codes and regulation that incorporate safety, reliability, and electrical
performance into the design of transmission lines. This approach to the design,
construction, and operation of Segment E-8 will establish utmost reliability for the life of
the transmission line.
16. The basic components of a transmission line are the structures/towers,
phase conductors, insulators, foundations to support the structures, and shield wires to
prevent lightning from striking conductors. Segment E-8 will be constructed using
approximately 540 structures utilizing self-supported single-circuit lattice. The self-
supporting steel lattice structures will be fabricated with galvanized steel members treated
to produce a dulled galvanized finish. The average distance between 500-kV structures,
or span, typically will range between 1,200 to 1,300 feet with occasional longer spans in
challenging terrain. Structure heights will vary depending on the terrain and the
requirement to maintain minimum conductor clearances from the ground, but the 500-kV
single-circuit structures will vary in height from approximately 145 to 199 feet. Each
APPLICATION - 10

transmission line structure type is individually designed, depending on the line angle and
the underlying soil and rock conditions, to withstand the pull of the wires in different
directions and will be set on self-supporting cast-in-place concrete drilled piers. In
accordance with the National Electrical Safety Code guidelines, Segment E-8 is designed
for wind and ice loads at the specified strength requirements, sufficient to resist
earthquake ground motions.
17. Construction of Segment E-8 is expected to commence in October 2027
and will be performed in three phases, though the scope of work is consistent across
each phase and includes all necessary vegetation management, access road
construction, pull-site construction, foundations, self-supporting lattice steel structure
supply and installation, phase conductor, static wire, optical ground wire and hardware
supply and installation, along with commissioning, testing and restoration. The first phase
of the project, the Mayfield Maintenance Section, will include construction of
approximately 17 miles of the transmission line, consisting of 68 structures, phase
conductor, static wire and optical ground wire. In addition, two cutover sections will be
constructed, and the realignment of approximately five structures will be performed.
18. Phase II, the Hemingway to Crossover #1 section, consists of the
construction of 126 structures that extend approximately 30 miles, beginning at the
Hemingway substation and connecting to Crossover#1 built in Phase I. During Phase III,
the Crossover #2 to Midpoint section, the remaining 84 miles of the new line will be
constructed, and construction of the communication regeneration site will occur. Phases
I and II include the construction of Segment E-8 from the Hemingway substation to the
Mayfield substation along with the necessary crossovers and provides for energization of
APPLICATION - 11

the Hemingway to Mayfield section once completed in late 2028. Phase III, the Mayfield
to Midpoint section of Segment E-8, will follow with energization of the second section
targeted to occur in summer 2030. Based on the most recent forecast of costs associated
with permitting, pre-construction activities, construction of Segment E-8 and substation
work, as well as a contingency, overheads, and Allowance for Funds Used During
Construction, the total cost of the project is approximately
19. In January 2026, Idaho Power began the competitive solicitation process to
secure a contractor for material procurement and construction of Segment E-8. A formal
Request for Proposal event is anticipated in July 2026. Execution of a construction
contract is expected to occur by December 2026 to allow for the commencement of
construction in October 2027. As such, the Parties are requesting the Commission issue
the CPCNs no later than October 31, 2026, prior to the Parties entering into any contracts
associated with material procurement and construction of Segment E-8. A final
Commission decision in October 2026 is critical to allowing for commencement of
construction of the project in time to meet the November 2028 in-service date.
VI. SEGMENT E-8 PROJECT BENEFITS
20. Benefits associated with the addition of Segment E-8 include the bolstering
of transmission capabilities to support load growth and the improved ability to interconnect
new generation resources between the Magic Valley and the Treasure Valley areas.
Segment E-8 will provide additional operational flexibility for transmission outages and
reduce the risk of automated generation curtailment that exists on today's transmission
system. Currently, the Midpoint West path consists of one 500-kV transmission line
between the Midpoint and Hemingway substations, three 230-kV transmission lines
APPLICATION - 12

between Midpoint and Boise Bench substations and two 138-kV transmission lines into
the Mountain Home area. The Midpoint West transmission lines facilitate the bidirectional
transfer of energy between the Magic Valley and Treasure Valley, with flow primarily east-
to-west to transmit eastern energy into Idaho Power's primary load center in the Treasure
Valley.
21. Recent studies indicate that the pre-Segment E-8 Idaho Power
transmission system can only accommodate approximately 250 MW of additional
Treasure Valley load above late-2020s levels. System imports from the east and south,
including the 700 MW of future Four Corners capacity, gained through the B2H asset
exchange, and SWIP-North capacity gained, as well as generation from existing
resources, must all cross the Midpoint West path to reach the Treasure Valley load.
Therefore, to meet any growth on the system, Idaho Power must either build new
generation close to the Treasure Valley or must increase transmission capability into the
region. It is infeasible from both a permitting and land perspective to site the magnitude
of resources in, or adjacent to, the Treasure Valley. Further, with respect to west-to-east
transmission capacity, Idaho Power relies heavily on this capacity for purchasing low-cost
power from the Pacific Northwest, however most of the transmission capacity is allocated,
including the capacity gained with B2H. With the transmission capabilities to serve
incremental demand currently limited, Segment E-8 will provide additional transmission
capability, both east-to-west and west-to-east.
22. Segment E-8 has been identified as an optimal project as part of the
generator interconnection studies, part of the process for which any new resources must
follow to interconnect to Idaho Power's system, for several years as the project allows for
APPLICATION - 13

the existing 230-kV system between Midpoint and the Treasure Valley to be repurposed.
Today, two 230-kV lines run directly from Midpoint to the Boise Bench substation which
are series compensated, and therefore difficult to split or reroute to accommodate the
interconnection of new resources without significantly decreasing the path rating.
However, with the addition of Segment E-8, these existing lines will no longer be a main
source of transmission service between the Magic Valley and the Treasure Valley,
allowing for the reduction or complete removal of the series compensation from the 230-
kV lines, and the ability to interconnect new generation resources with a lower impact on
the post-Segment E-8 Midpoint West path rating.
23. Because Idaho Power's Midpoint West path is currently congested, any
sustained outages on the path reduce Idaho Power's ability to transmit generation to
serve load. Should the Midpoint to Hemingway 500-kV line be out of service, Idaho Power
must restrict actual flows east-to-west on the Midpoint West path to maintain compliance.
This results in a reduction of approximately 2,500 MW of east-to-west capacity across
Idaho Power's transmission system. To continue to serve load on the east-to-west path,
the Company must then reduce transmission schedules pro-rata with other firm, east-to-
west reservations to accommodate the reduced transmission capacity. Depending on
system stress, loss of Midpoint to Hemingway 500-kV line can be one of the most severe
outages on Idaho Power's transmission system. With the addition of Segment E-8, a
second 500-kV path for transfers between the Magic Valley and Treasure Valley would
be available, allowing for the redistribution of flow during an outage. This noticeably
increases the expected transfer capability under outage conditions, reducing the
APPLICATION - 14

likelihood that transmission related curtailments will be severe, and allows Idaho Power
to continue to serve customer load effectively and economically.
VII. CERTIFICATES OF PUBLIC CONVENIENCE AND NECESSITY
24. The Parties have an obligation to provide adequate, efficient, just, and
reasonable service on a nondiscriminatory basis to all those that request it within their
certificated service territory. Idaho Code §§ 61-302, 61-315, 61-507. The Commission
must assure that the rates Idaho Power and PacifiCorp charge their customers and that
the rules and regulations by which they provide service are just, reasonable,
nondiscriminatory, and non-preferential. Idaho Code §§ 61-501 , 61-502, 61-503, 61-507,
61-508. Segment E-8 of Gateway West will create up to 2,000 MW of additional
transmission capacity, allowing continued adequate system reliability and providing the
ability to interconnect new generation resources across Idaho. Each of the Parties
therefore are requesting an order from the Commission affirming that the public
convenience and necessity require the same. The Commission has the express authority
to order a utility to build new structures, or to upgrade and/or improve existing plant and
structures, in order to secure adequate service or facilities.
Whenever the commission, after a hearing had upon its own
motion or upon complaint, shall find that additions,
extensions, repairs or improvements to or changes in the
existing plant, scales, equipment, apparatus, facilities or other
physical property of any public utility . . . ought reasonably to
be made, or that a new structure or structures should be
erected, to promote the security or convenience of its
employees or the public, or in any other way to secure
adequate service or facilities, the commission shall make and
serve an order directing such additions, extensions, repairs,
improvements, or changes be made or such structure or
structures be erected in the manner and within the time
specified in said order.
Idaho Code § 61-508.
APPLICATION - 15

25. A CPCN or Certificate represents the exercise by the Commission of
foundational authority and principles that are necessary in Idaho's system of permitting
regulated, vertically integrated, public utilities to exist and to provide necessary services
to the public. Certificates have been utilized in various ways from the time that Idaho's
statutory system of public utility regulation was enacted by the Legislature in 1913, Idaho
Code § 61-101, et seq., to the present time. After nearly 100 years of legislative
enactments, Commission orders, and Idaho Supreme Court reviews, the Certificate
remains the embodiment of the Commission's fundamental power and authority to, at the
most basic level, authorize and direct a public utility to serve in the public interest. See
Idaho Power& Light Co. v. Blomquist et al., 26 Idaho 222, 141 P.1083 (1914); Idaho Op.
Atty. Gen. No. 87-2, 1987 WL 247587 (Idaho A.G.).
26. In the broadest sense, a Certificate allows a company that meets the
definition of a "public utility" pursuant to Idaho Code § 61-129 to exclusively provide its
service to the public in a specified geographic region, its service territory. It is a codified
part of the "regulatory compact" whereby the utility takes on the exclusive obligation/right
to serve all those requesting service within its service territory and, correspondingly,
submits itself to the rate and service quality regulation of the Commission. In a more literal
sense, a Certificate from the Commission is required for the construction or extension of
a line, plant, or system by any street, railroad, gas, electrical, telephone, or water
corporation. Idaho Code § 61-526. § 61-526 also provides that "if public convenience
and necessity does not require or will require such construction or extension [of a line,
plant, or system] the commission . . . may, after hearing, make such order and prescribe
such terms and conditions for the locating or type of line, plant or system affected as to it
may seem just and reasonable . . . ." A CPCN is required for the utility to construct a new
APPLICATION - 16

generation resource, plant, or line but is not required to increase the capacity of existing
generating facilities. Id.
VIII. RATEMAKING TREATMENT FOR SEGMENT E-8
27. The Parties are not requesting binding ratemaking treatment for Segment
E-8 in this case, rather the request in this case is that the Commission find that both Idaho
Power and PacifiCorp have met the requirements of Idaho Code § 61-526 and issue an
order for each Party granting a CPCN for Segment E-8, which will create up to 2,000 MW
of additional transmission capacity, allowing continued adequate system reliability and
providing the ability to interconnect new generation resources across Idaho. The Parties
will each make separate future filings to address cost recovery associated with the
project.
IX. FINANCING SEGMENT E-8 OF GATEWAY WEST
28. Idaho Power maintains investment grade credit ratings with Standard &
Poor's Ratings Services and Moody's Investors Service, with a long-term issuer rating of
BBB and Baa2, respectively. The Company maintains ready access to the capital markets
and to instruments providing for its liquidity. Idaho Power has a $400 million revolving
credit facility with its banking syndicate, which may be increased to $600 million under
specified conditions, which matures on December 6, 2030. Idaho Power has an option to
request two additional one-year extensions of the agreement, subject to certain
conditions. Idaho Power completed a successful $350 million first mortgage bond offering
in February 2026 under existing regulatory authority. In the second quarter of 2026,
Idaho Power anticipates requesting approval from the Commission for the ability to issue
up to $1.35 billion in aggregate principal amount of debt securities. Idaho Power also has
access to commercial paper markets, as well as a balance of cash and investments on
its balance sheet.
APPLICATION - 17

29. Additionally, Idaho Power has access to capital and credit outside of
existing mechanisms and instruments, such as through term loans, letters of credit, and
other instruments. IDACORP sold an additional 6,434,350 shares of common stock on
various forward sale agreements between November 2024 and May 2025. The
approximate cash value remaining on the forward sale agreements, if settled for
IDACORP shares, was $613 million as of December 31, 2025. Idaho Power intends to
finance Segment E-8 with a combination of available cash and operating cash flow,
available credit facilities and borrowing and debt issuances, and future equity infusions
by IDACORP.
30. PacifiCorp intends to finance the project through its normal sources of
capital, both internal and external, including potentially the use of net cash flow from
operating activities, public and private debt offerings, the issuance of commercial paper,
the use of unsecured revolving credit facilities, capital contributions and other sources.
The financial impact of the investment will not impair PacifiCorp's ability to continue to
provide safe and reliable electricity service at reasonable rates. In addition, approval of
the investment decision provides important regulatory support for PacifiCorp's current
credit rating.
X. COMMUNICATIONS AND SERVICE OF PLEADINGS
31. Communications and service of pleadings with reference to this Application
should be sent to the following:
APPLICATION - 18

Lisa C. Lance Tim Tatum
Corporate Counsel Connie Aschenbrenner
Idaho Power Company Idaho Power Company
1221 West Idaho Street (83702) 1221 West Idaho Street (83702)
P.O. Box 70 P.O. Box 70
Boise, Idaho 83707 Boise, Idaho 83707
IlanceCcD.idahopower.com ttatumCcDidahopower.com
dockets idaho power.com caschenbrenner(a)_idahopower.com
Joe Dallas Jana Saba
Assistant General Counsel Regulatory Affairs Manager
PacifiCorp Rocky Mountain Power
825 NE Multnomah Street, Suite 2000 1407 West North Temple, Suite 330
Portland, Oregon 97232 Salt Lake City, Utah 84116
joseph.dallas(a�pacificorp.com jana.saba(o)pacificorp.com
XI. MODIFIED PROCEDURE
32. The Parties believe that a hearing is not necessary to consider the issues
presented herein, and respectfully requests that this Application be processed under
Modified Procedure; i.e., by written submissions rather than by hearing. RP 201, et seq.
If, however, the Commission determines that a technical hearing is required, the Parties
stand ready to present their testimony and support the Application in such hearing.
XII. REQUEST FOR RELIEF
Segment E-8 will create up to 2,000 MW of additional transmission capacity,
allowing continued adequate system reliability and providing the ability to interconnect
new generation resources across Idaho. The Parties respectfully request that the
Commission find Segment E-8 to be in the public interest and grant each Party a CPCN
allowing for the commencement of construction of Segment E-8. The Parties respectfully
request the Commission issue a CPCN no later than October 31 , 2026, prior to the Parties
entering into any contracts associated with construction of Segment E-8.
APPLICATION - 19

DATED this V day of April 2026.
/11 G/°�
LISA C. LANCE
Attorney for Idaho Power Company
JOSEPH DALLAS
Attorney for PacifiCorp
APPLICATION - 20