HomeMy WebLinkAbout20260403Direct Ellsworth.pdf RECEIVED
APRIL 3, 2026
IDAHO PUBLIC
UTILITIES COMMISSION
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 )
500-KV TRANSMISSION LINE . )
IDAHO POWER COMPANY
DIRECT TESTIMONY
OF
JARED L. ELLSWORTH
1 Q. Please state your name, business address, and
2 present position with Idaho Power Company ("Idaho Power" or
3 "Company") .
4 A. My name is Jared L. Ellsworth and my business
5 address is 1221 West Idaho Street, Boise, Idaho 83702 . I am
6 employed by Idaho Power as the Transmission, Distribution &
7 Resource Planning Director for the Planning, Engineering &
8 Construction Department.
9 Q. Please describe your educational background.
10 A. I graduated in 2004 and 2010 from the
11 University of Idaho in Moscow, Idaho, receiving a Bachelor
12 of Science Degree and Master of Engineering Degree in
13 Electrical Engineering, respectively. I am a licensed
14 professional engineer in the State of Idaho.
15 Q. Please describe your work experience with
16 Idaho Power.
17 A. In 2004, I was hired as a Distribution
18 Planning engineer in the Company' s Delivery Planning
19 department. In 2007, I moved into the System Planning
20 department, where my principal responsibilities included
21 planning for bulk high-voltage transmission and substation
22 projects, generation interconnection projects, and North
23 American Electric Reliability Corporation' s reliability
24 compliance standards . I transitioned into the Transmission
25 Policy & Development group with a similar role, and in
ELLSWORTH, DI 1
Idaho Power Company
1 2013, I spent a year cross-training with the Company' s Load
2 Serving Operations group. In 2014, I was promoted to
3 Engineering Leader of the Transmission Policy & Development
4 department and assumed leadership of the System Planning
5 group in 2018 . In early 2020, I was promoted into my
6 current role as the Transmission, Distribution & Resource
7 Planning Director. I am currently responsible for the
8 planning of the Company' s wires and resources to continue
9 to provide customers with cost-effective and reliable
10 electrical service.
11 Q. What are the parties requesting in this
12 case?
13 A. Idaho Power and PacifiCorp d/b/a Rocky
14 Mountain Power and Pacific Power (collectively referred to
15 as "PacifiCorp") (together, the "Parties" or "each Party")
16 are requesting the Idaho Public Utilities Commission
17 ("Commission") issue an order granting Idaho Power and
18 PacifiCorp each a Certificate of Public Convenience and
19 Necessity ("CPCN") for Segment E-8 of the Gateway West 500-
20 kV line ("Segment E-8") . Segment E-8 of Gateway West will
21 create up to 2, 000 megawatts ("MW") of additional
22 transmission capacity, allowing the Company to maintain
23 adequate system reliability and providing the ability to
24 interconnect new generation resources across Idaho. In this
ELLSWORTH, DI 2
Idaho Power Company
1 proceeding, the Parties request that the Commission find
2 Segment E-8 of Gateway West to be in the public interest
3 and grant each Party a CPCN allowing for the commencement
4 of construction of Segment E-8 . The Parties respectfully
5 request the Commission issue the CPCNs no later than
6 October 31, 2026, prior to the Parties entering into any
7 contracts associated with construction of Segment E-8 .
8 Q. How is the case organized?
9 A. The case begins with my testimony in which I
10 present an overview of the Gateway West transmission
11 project, describing Segment E-8 of Gateway West which is
12 jointly owned by the Parties . Next, I will discuss the
13 identification of the Gateway West project in the Regional
14 Transmission Plans and the inclusion of Gateway West as
15 part of Idaho Power' s Integrated Resource Planning ("IRP")
16 process, detailing the Gateway West analysis performed as
17 part of the 2023 IRP, subsequently refined in the 2025 IRP,
18 as a necessary transmission investment to cost-effectively
19 enable incremental resource additions . Finally, I will
20 describe the benefits associated with the addition of
21 Segment E-8, including the bolstering transmission
22 capability to support system load growth and the improved
23 ability to interconnect new generation resources .
24 The Direct Testimony of PacifiCorp witness Mr. Rick
25 Vail discusses PacifiCorp' s current ownership of Segment E-
ELLSWORTH, DI 3
Idaho Power Company
1 8 in accordance with the structure of the Gateway West
2 Joint Permit Funding Agreement, including the associated
3 amendments . In addition, he describes PacifiCorp' s need for
4 Segment E-8 to meet its customers' short- and long-term
5 energy demand and for strengthening of the overall
6 reliability of the existing transmission system. Lastly,
7 Mr. Vail details the pre-construction activities undertaken
8 to obtain necessary federal, state, and local permits and
9 other project development work.
10 Finally, the Direct Testimony of Idaho Power Witness
11 Ms . Lindsay Barretto describes Idaho Power' s involvement in
12 Segment E-8 pre-construction activities performed by
13 PacifiCorp. Next, Ms . Barretto provides a description of
14 the transmission line design of Segment E-8 and the
15 standards and guidelines for which it will be constructed
16 and operated. Lastly, Ms . Barretto describes the planned
17 Segment E-8 construction activities and discusses the total
18 estimated costs associated with the project.
19 Q. Have you prepared any exhibits?
20 A. Yes . Exhibit No. 1 includes a map of the
21 nearly 1, 000-mile Gateway West transmission project.
22 Exhibit No. 2 is a map of the nearly 133-mile Segment E-8
23 of the Gateway West transmission project. Exhibit No. 3 to
24 my testimony illustrates the transmission projects selected
ELLSWORTH, DI 4
Idaho Power Company
1 into the 2024-2025 Regional Transmission Plan, identifying
2 Segment E-8 of Gateway West as a key component of the plan.
3 I . THE GATEWAY WEST TRANSMISSION PROJECT
4 Q. Please describe the Gateway West transmission
5 project .
6 A. To understand the Gateway West transmission
7 project, I will first describe PacifiCorp' s Gateway
8 Transmission Expansion Program ("Energy Gateway") , a plan
9 to build over 2, 300 miles of new high-voltage transmission
10 lines, primarily in Wyoming, Utah, Idaho and Oregon. '
11 Energy Gateway includes transmission lines in the Gateway
12 Central, Gateway West, Gateway South, and West of
13 Hemingway regions, with routes within the regions
14 identified as Segments A through H. The Gateway West
15 project includes the addition of approximately 1, 000 miles
16 of transmission lines identified as Segments D and E and
17 will run from the planned Windstar substation near
18 Glenrock, Wyoming, to the Hemingway substation near Melba,
19 Idaho, when completed. Segments D and E are further
20 categorized into Segments 1 through 10 . Exhibit No . 1 to
21 my testimony includes a map of the Gateway West segments,
22 identifying the authorized routes in the federal
23 permitting process based on the Bureau of Land
24 Management' s ("BLM") November 2013 Record of Decision
' Energy Gateway
ELLSWORTH, DI 5
Idaho Power Company
1 ("ROD") for Segments 1 through 7 and 10 and the BLM' s 2018
2 ROD for Segments 8 and 9 .2
3 Q. Have any portions of Gateway West been
4 constructed?
5 A. Yes . Following PacifiCorp' s announcement in
6 2017 of plans to construct a portion of Gateway West in
7 Wyoming, PacifiCorp subsequently constructed the 140-mile
8 segment between the Aeolus substation near Medicine Bow,
9 Wyoming, and the Jim Bridger Power Plant ("Bridger") near
10 Point of Rocks, Wyoming. The Aeolus to Anticline 500-kV
11 line segment was energized in November 2020 .
12 Q. Does Idaho Power have an ownership interest in
13 all Segments 1 through 10 of Gateway West?
14 A. No. While PacifiCorp has an ownership interest
15 in all segments of Gateway West, Idaho Power only has an
16 ownership interest in Segment 8, which runs between the
17 Midpoint and Hemingway substations, Segment 9, which runs
18 between the future Cedar Hill substation and the Hemingway
19 substation, and Segment 10, which runs between the future
20 Cedar Hill substation and the Midpoint substation. In
21 addition, Idaho Power has interest in Segment 6, between
22 the Borah and Midpoint substations, which is an existing
23 transmission line operated at 345-kV but constructed at
24 500-kV. However, as part of this proceeding, the Parties
2 Gateway West Transmission Project Interactive Map.
ELLSWORTH, DI 6
Idaho Power Company
1 are each requesting a CPCN for Segment E-8 only.
2 Q. Please describe Segment E-8 .
3 A. Segment E-8 is an approximately 133 mile 500-
4 kV line that will run from the Midpoint substation, near
5 Jerome, Idaho, to the Hemingway Substation, near Melba,
6 Idaho. The Segment E-8 line will connect to Idaho Power' s
7 proposed 500-kV Mayfield substation, located near
8 Mayfield, Idaho, resulting in two sections of the Segment
9 E-8 line, the approximately 40-mile Hemingway to Mayfield
10 500-kV line and the approximately 90-mile Mayfield to
11 Midpoint 500-kV line . A map of Segment E-8 within the
12 Gateway West transmission project is included as Exhibit
13 No. 2 to my testimony.
14 Q. How much additional capacity will be provided
15 with the addition of Segment E-8 of Gateway West?
16 A. Segment E-8 will create approximately 2, 000 MW
17 of additional needed transmission capacity on Idaho
18 Power' s Midpoint West and Boise East transmission paths,
19 which are currently fully subscribed and utilized. The
20 increased capacity on these paths will support
21 bidirectional transfers between the Magic and Treasure
22 Valleys . The project will support delivery of energy to
23 the Treasure Valley from planned new resource
24 interconnections in the Mountain Home and Magic Valley
25 areas . As new resources are added near the Treasure
ELLSWORTH, DI 7
Idaho Power Company
1 Valley, Segment E-8 will also support economic transfers
2 of west-to-east energy to serve growth in the Magic Valley
3 area. Currently, Idaho Power will have 99 percent
4 ownership interest in the capacity of Segment E-8 and
5 PacifiCorp will have the remaining one percent ownership
6 interest.
7 II . RESOURCE PLANNING MODELING OF GATEWAY WEST
8 Q. Did Idaho Power model its ownership interest
9 in Segment E-8 of Gateway West as part of its planning
10 processes?
11 A. Yes . Gateway West was first identified through
12 the Northern Tier Transmission Group ("NTTG") regional
13 transmission planning procesS3 conducted in 2007, along
14 with the 2008-2009 biennial planning process . This process
15 involves the evaluation of the region' s transmission
16 needs, in the 10-year planning horizon, as determined by
17 state mandated IRPs and load forecasts, proposed resource
18 development and generation interconnection queues, and
19 forecast uses of the transmission system by wholesale
20 transmission customers . By identifying potential resource
3 The regional transmission planning process is developed in accord with each
transmission provider's Attachment K of their Open Access Transmission Tariff,
which includes Federal Energy Regulatory Commission Order 1000 regional and
interregional transmission planning requirements. The Regional Transmission
Plan analyzes whether the member utilities' transmission needs could be best
satisfied with project of a regional or interregional scope. Current members of
the regional planning organization include Avista, Bonneville Power
Administration, Chelan PUD, Idaho Power, the Montana Alberta Tie Line,
Northwestern Energy, NV Energy, PacifiCorp, Portland General Electric, Puget
Sound Energy, Seattle City Light, Snohomish PUD, and Tacoma Power.
ELLSWORTH, DI 8
Idaho Power Company
1 areas and load center growth, the required transmission
2 capacity expansions to safely and reliably provide service
3 to customers are identified. Components of the Gateway
4 West project have been consistently selected in each NTTG
5 biennial regional transmission plan from 2007 through
6 2019, and in the NorthernGrid, NTTG' s successor regional
7 planning organization, 2020-2021, 2022-2023, and 2024-2025
8 Regional Transmission Plans . Segment E-8 specifically, was
9 selected within the 2022-2023 and 2024-2025 NorthernGrid
10 biennial Regional Transmission Plans . Exhibit No . 3 to my
11 testimony illustrates the transmission projects selected
12 into the 2024-2025 Regional Transmission Plan, identifying
13 Segment E-8 of Gateway West as a key component of the
14 plan.
15 Q. How does the regional transmission planning
16 process identify benefits associated with transmission
17 projects of member utilities?
18 A. The NorthernGrid planning studies use
19 production cost modeling that incorporate loads and
20 resources from the member utility data submittals,
21 resulting in an hourly representation of transmission
22 flows for every hour of year 10 of the planning future, or
23 2034 in the most recent case . Next, a diverse subset of
24 hours is selected to represent varying predicted
25 transmission flow conditions on the NorthernGrid member
ELLSWORTH, DI 9
Idaho Power Company
1 utility footprint to be studied extensively in a powerflow
2 analysis with the intent of identifying voltage excursions
3 and thermal overloads that may arise following unplanned
4 contingencies . Through this process, Gateway West was
5 identified as cost-effectively or efficiently meeting the
6 needs within the NorthernGrid region.
7 Q. What benefits of Gateway West were identified
8 specific to Idaho as part of this process?
9 A. Gateway West was identified in the Regional
10 Transmission Plan to mitigate forecasted thermal overload
11 violations primarily identified for east-to-west transfer
12 hours across Southern Idaho. Segment E-8 specifically was
13 selected to create more Midpoint West capacity and
14 determined to be more cost-effective or efficient to meet
15 the needs of southern Idaho within the NorthernGrid
16 footprint.
17 Q. Once identified in the Regional Transmission
18 Plan, did Idaho Power model Gateway West as part of the
19 Company' s IRP process to assess the economic and
20 operational benefits specific to Idaho Power and its
21 customers?
22 A. Yes . Following identification in the regional
23 transmission plans, Gateway West was first considered as
24 part of Idaho Power' s 2009 IRP. In the latter half of the
25 planning horizon of the 2009 IRP, 2020-2029, the Gateway
ELLSWORTH, DI 10
Idaho Power Company
1 West project was included in every portfolio because then-
2 current constraints would require the addition of new
3 transmission capacity for resources to be added in
4 southern Idaho, east of the Treasure Valley load center.
5 Gateway West was again modeled in the 2011 and 2013 IRPs,
6 and beginning with the 2015 IRP, Idaho Power began
7 modeling Segment E-8 separately from other segments of
8 Gateway West as part of the IRP process .
9 Q. What were the results of the IRP modeling once
10 the Gateway West segments were separately modeled?
11 A. The results indicated that the Gateway West
12 segments in which Idaho Power had ownership remained a key
13 future resource to Idaho Power and the region, promoting
14 continued grid reliability in a time of expanding energy
15 resources and therefore, the action plan included
16 continued permitting and planning associated with the
17 Gateway West project. Idaho Power continued modeling the
18 segments of the Gateway West project for which it had an
19 ownership interest as part of subsequent IRPs until the
20 2023 IRP when a more robust analysis was performed.
21 Q. How was the modeling of Gateway West changed
22 as part of the 2023 IRP process?
23 A. Unlike the Boardman-to-Hemingway ("B2H") or
24 the Southwest Intertie Project ("SWIP") -North transmission
25 lines, the Gateway West project does not individually
ELLSWORTH, DI 11
Idaho Power Company
1 provide access to a liquid market hub, additional
2 transmission is needed to do so and therefore does not act
3 as a stand-alone resource . However, without Gateway West,
4 the number of incremental resources that can be added to
5 Idaho Power' s system is constrained. As such, the Gateway
6 West project was modeled as an enabling project to allow
7 the incremental resource additions to be interconnected on
8 the Idaho Power transmission system east of the Treasure
9 Valley.
10 Q. Where are the current transmission constraints
11 that Gateway West will relieve?
12 A. The transmission capacity directly associated
13 with Gateway West will relieve four primary transmission
14 constraints : (1) east-to-west transmission capacity
15 between eastern Idaho and the Magic Valley ("Borah West") ,
16 (2) east-to-west transmission capacity between the Magic
17 Valley and the Treasure Valley ("Midpoint West") , (3)
18 east-to-west transmission capacity between the Mountain
19 Home area and the Treasure Valley ("Boise East") , and (4)
20 west-to-east transmission capacity between the Treasure
21 Valley and Magic Valley ("Midpoint West" eastbound
22 capacity) . The primary transmission constraints for adding
23 new resources east of the Treasure Valley are the Midpoint
24 West and Boise East paths . Segment E-8, Segment E-9, and
25 Segment E-10 will increase the transfer capability for
ELLSWORTH, DI 12
Idaho Power Company
1 both the Midpoint West and Boise East paths . The addition
2 of Segment E-8 is also expected to increase east-to-west
3 transmission capacity between Idaho and the Pacific
4 Northwest by reinforcing the Midpoint to Hemingway 500-kV
5 bottleneck and increase west-to-east transmission capacity
6 between the Pacific Northwest and Idaho . I will discuss
7 these last two benefits later in my testimony.
8 Q. How did the Company model Gateway West in the
9 2023 IRP?
10 A. For Idaho Power' s 2023 IRP modeling, the
11 Company assumed that the split of ownership and capacity
12 would align with the Parties' respective allocated
13 permitting costs . For Idaho Power, this included interest
14 in Segment E-8, Segment E-9, and Segment E-10 . Segments E-
15 8 and E-9, the two primary east-to-west segments between
16 the Magic Valley and the Treasure Valley areas, were
17 assumed to each provide 2, 000 MW of capacity, of which 667
18 MW of capacity per segment would be Idaho Power' s
19 allocated share, assumed at the time . In addition,
20 modeling of the 2023 IRP allowed for the selection of up
21 to 1, 725 MW of incremental variable resources to be
22 interconnected to the existing grid, between 2024 and
23 2028, prior to the need to construct the first phase of
24 Gateway West. Beyond 1, 725 MW of incremental variable
25 resources, the analysis modeled each subsequent Gateway
ELLSWORTH, DI 13
Idaho Power Company
1 West addition as enabling 1, 000 MW of incremental variable
2 resources onto the system.
3 Q. Does this mean that each segment, Segments E-
4 8, E-9 and E-10, enable 1, 000 MW of incremental resources
5 for a total of 3, 000 MW?
6 A. No. Table 1 below presents the Gateway West
7 phase modeling performed as part of the 2023 IRP. Segments
8 E-8 and E-10, combined with Idaho Power' s Mayfield
9 substation, were modeled to enable 1, 000 MW of incremental
10 resource capacity and Segment E-9 was modeled to enable an
11 additional 1, 000 MW of incremental resource capacity. In
12 addition, the Company modeled a future, not yet permitted
13 transmission addition, a Midpoint-Mayfield 500-kV
14 transmission line ("Midpoint-Mayfield") , which was modeled
15 to enable 2, 000 MW of incremental resources . The Company
16 anticipated Midpoint-Mayfield would be a rebuild of an
17 existing 230-kV line but with an in-service date in 2039 .
18 Table 1 . 2023 IRP - Gateway West phase modeling.
Incremental Cost
In-Service Resource Capacity (Levelized per
Phase Date* Enabled year)'*
Midpoint—Hemingway#2 500-kV(Segment 8), 12/2028* 1,000 $42.3 million
and Midpoint—Cedar Hill500-kV(Segment 10),
and Mayfield substation
Cedar Hill—Hemingway 500-kV(Segment 9) 12/2030* 1,000 $25.2million
and Cedar Hill substation
Future non permitted phase:Midpoint—Mayfield 12/2039 2,000 $21.7 million
500-kV
*Idaho Power will continue to work with PacifiCorp on the timing and need for these Gateway West segments.
19 **The levelized costs in this table do not reflect offsetting transmission revenues from Idaho Power transmission customers.
20
ELLSWORTH, DI 14
Idaho Power Company
1 Q. What was the intent of the Gateway West phase
2 modeling performed as part of the Company' s 2023 IRP?
3 A. The purpose of the Gateway West phase modeling
4 was to test the cost effectiveness of the various Gateway
5 West phases, allowing Idaho Power to develop differing
6 portfolios with the additions of Gateway West . The Company
7 included all three phases of Gateway West in the baseline
8 portfolios, including the cost, and compared those
9 portfolios to three additional resource portfolios : (1) a
10 portfolio that did not include any of the Gateway West
11 phases ("Without GWW Phases") , (2) a portfolio that
12 included only the permitted phases of Gateway West, or
13 Segments E-8, E-9, and E-10, ("GWW Phase 1 & 2") , and (3)
14 a portfolio that included only Gateway West phase 1, or
15 Segment E-8 ("GWW Phase 1 Only") . When modeling the
16 various without Gateway West portfolios, Aurora' s Long-
17 Term Capacity Expansion modeling platform was prevented
18 from selecting incremental resources east of the Treasure
19 Valley above defined levels and instead would have been
20 required to select resource options closer to loads within
21 the Treasure Valley.
22 Q. What were the results of the Company' s 2023
23 IRP analysis modeling the with and without Gateway West
24 portfolios?
25
ELLSWORTH, DI 15
Idaho Power Company
1 A. The net present value ("NPV") of the resource
2 portfolios modeled as part of Idaho Power' s 2023 IRP are
3 shown in Table 2 below. As can be seen, the Without GWW
4 Phases portfolio is $580 million higher on an NPV basis
5 than the Preferred Portfolio that includes all three
6 phases of Gateway West. A portfolio with GWW Phase 1 Only
7 was $517 million higher on a NPV basis than the 2023 IRP
8 Preferred Portfolio and the GWW Phases 1 & 2 Only
9 portfolio is approximately $10 million higher on an NPV
10 basis .
11 Table 2 . 2023 IRP main cases .
Portfolio NPV years 2024-2043($x 1,000,000)
Preferred Portfolio(Valmy 1 &2) $9,746
Valmy 2 $9,795
Without Valmy $9,824
Nov2026 132H Valmy 1&2 $9,767
Nov2026 132H Valmy 2 $9,880
Nov2026 132H Without Valmy $10,192
Without B2H $10,582
Without GWW Phases $10,326
GWW Phase 1 Only $10,263
GWW Phases 1 &2 Only $9,759
12
13 As a result, Idaho Power' s 2023 IRP Near-Term Action Plan
14 for the 2024-2028 time period included bringing the first
15 phase of Gateway West, Segments E-8 and E-10 and the
16 construction of Idaho Power' s Mayfield substation, online.
17 Q. You indicated the Company' s 2023 IRP Gateway
18 West analysis modeled incremental capacity based on Idaho
19 Power' s ownership interest at the time . Has the Company' s
ELLSWORTH, DI 16
Idaho Power Company
1 interest in the project changed since then?
2 A. Yes . At the time modeling for the 2025 IRP
3 commenced, more clarity had been gained regarding Idaho
4 Power and PacifiCorp' s participation in Gateway West with
5 the likelihood that the Company would control 99 percent
6 of the capacity. Therefore, Idaho Power refined the 2025
7 IRP modeling of Gateway West, updating its ownership
8 percentage, and moved away from modeling the project as a
9 three-phase approach.
10 Q. Did the Company' s share of the incremental
11 capacity increase with the increase to 99 percent in the
12 ownership of Segment E-8?
13 A. Yes . Along with the increased ownership
14 percentage, Idaho Power' s incremental capacity on Segment
15 E-8 increased to 1, 980 MW. Additionally, the Company was
16 also able to defer Segment E-10 as it is essentially being
17 built through the addition of the SWIP-North, for which
18 the Commission granted Idaho Power a CPCN in Case No . IPC-
19 E-25-08 . SWIP-North will follow nearly the same route as
20 Segment E-10, and the Company will further leverage this
21 component of the SWIP-North 500-kV line in the future .
22 Q. Does the Company anticipate it will fully
23 utilize its increased ownership of capacity of the line?
24 A. Yes . When developing the 2025 IRP portfolios,
25 it had also become clear that developing a portfolio
ELLSWORTH, DI 17
Idaho Power Company
1 without Segment E-8, even at the increased capacity level,
2 was not a possibility; with load growth over the 20-year
3 planning horizon being focused heavily on the Treasure
4 Valley area, absent the addition of Segment E-8, new
5 resources must be sited within the Treasure Valley area
6 which has proven to be challenging. As evidenced by the
7 Company' s recent responses to its Request for Proposals
8 ("RFP") , most of the resource proposals submitted in
9 response to the RFP have been east of the Treasure Valley.
10 Q. How many resource additions did the 2025 IRP
11 consider that led the Company to the conclusion that they
12 could not all be sited in the Treasure Valley?
13 A. Idaho Power' s 2025 IRP portfolios included
14 2, 695 MW of new gas, wind, and solar generation resource
15 additions . Based on recent permitting experiences and
16 changes in laws, the Company does not believe it is
17 realistic to assume nearly 3, 000 MW of new resources could
18 all be sited within the Treasure Valley area. The limited
19 capacity available between the Magic Valley and Treasure
20 Valley area necessitates a transmission capacity upgrade
21 east of the Treasure Valley to support the increased
22 generation. Therefore, the addition of Segment E-8,
23 assuming the Company' s 99 percent ownership, or a 1, 980 MW
24 of incremental capacity, was modeled as a baseline
25 assumption to enable the incremental resource additions
ELLSWORTH, DI 18
Idaho Power Company
1 identified in the 2025 IRP. Gateway West Segment E-8 was a
2 key component of Idaho Power' s 2025 IRP Preferred
3 Portfolio.
4 III . SEGMENT E-8 OF THE GATEWAY WEST PROJECT BENEFITS
5 Q. What is driving the benefits of Segment E-8 as
6 modeled through the IRP process?
7 A. Benefits associated with the addition of
8 Segment E-8 include bolstering of transmission capability
9 to support load growth and the improved ability to
10 interconnect new generation resources between the Magic
11 Valley and the Treasure Valley areas . In addition, while
12 not a benefit identified through IRP modeling, Segment E-8
13 will provide additional operational flexibility for
14 transmission outages and reduce the risk of automated
15 generation curtailment that exists on today' s transmission
16 system. Prior to discussing these benefits, I will first
17 provide, in Figure 1 below, a visual representation of
18 Segment E-8 alongside Idaho Power' s existing 230-kV and
19 500-kV transmission lines, existing substations and the
20 future Mayfield substation, and their relation to the
21 Treasure Valley load center geographically.
22
23
24
25
ELLSWORTH, DI 19
Idaho Power Company
1 Figure 1 . Area of Discussion.
2
Treasure
Valley Load Boise Bench
Northwest
Flow Mayfield
Hemingway \
\ Midpoint West
230 kV lines Transmission Path
500 kV line — \ (230kV and Above)
—— GWW#8 \
_ Midpoint
Eastern
Flow
Southern
Flow
3
4 The Midpoint West path consists of one 500-kV transmission
5 line between the Midpoint and Hemingway substations, three
6 230-kV transmission lines between Midpoint and Boise Bench
7 substations and two 138-kV transmission lines into the
8 Mountain Home area. The Midpoint West transmission lines
9 facilitate the bidirectional transfer of energy between
10 the Magic Valley and Treasure Valley, with flow primarily
11 east-to-west to transmit eastern energy into Idaho Power' s
12 primary load center in the Treasure Valley.
13 Idaho Power's Transmission Import Capabilities
14 Q. Please describe the Company' s existing
15 transmission import rights that currently facilitate
16 capacity and energy market purchases, from regional market
17 power hubs, to serve system load.
ELLSWORTH, DI 20
Idaho Power Company
1 A. Idaho Power currently utilizes five
2 connections to neighboring utilities to make firm market
3 import purchases to serve system load, Idaho-Northwest
4 ("Path 14") , which will be bolstered by B2H in late-2027,
5 Idaho-Nevada ("Path 16") , Idaho-Montana ("Path 18") ,
6 Idaho-Wyoming ("Path 19") , and Idaho-Utah ("Path 20") . In
7 addition, through the B2H project asset exchange with
8 PacifiCorp, the Company will acquire 200 MW of
9 bidirectional capacity from Four Corners, which will be
10 imported on Path 20 beginning in 2027 . Also, once
11 completed in 2028, SWIP-North will provide an additional
12 500 MW of import capacity on the newly established Idaho-
13 Southern Nevada path.
14 Q. Is Idaho Power currently able to deliver all
15 imports to its primary load centers?
16 A. Recent studies indicate that the pre-Segment
17 E-8 Idaho Power transmission system can only accommodate
18 approximately 250 MW of additional Treasure Valley load
19 above late-2020s levels . Therefore, to meet any growth on
20 the system, Idaho Power must either build new generation
21 close to the Treasure Valley or the Company must increase
22 transmission capability into the region. As illustrated in
23 Figure 1, Segment E-8 will provide additional transmission
24 capability, both east-to-west and west-to-east .
25
ELLSWORTH, DI 21
Idaho Power Company
1 Q. Why does Idaho Power believe it will be
2 difficult to build new generation in or near the Treasure
3 Valley?
4 A. Idaho Power' s most recent IRP identified
5 nearly 3, 000 MW of necessary resources to cost-effectively
6 and reliably serve the Company' s incremental energy needs .
7 It is infeasible from both a permitting and land
8 perspective to site that magnitude of resources in, or
9 adjacent to, the Treasure Valley. Additionally, Idaho
10 Power' s experience through both recent RFPs and the
11 generator interconnection study process indicate that most
12 resource proposals are located east of the Treasure
13 Valley. Currently in Idaho Power' s generation
14 interconnection queue, when analyzing nameplate ratings,
15 over 40 percent of transmission interconnections are
16 requesting points of interconnection between the Magic
17 Valley and Treasure Valley with an additional 32 percent
18 of the queue east of the Midpoint West constraint .
19 Further, within the last couple years, the Company was
20 prepared to move forward with a least-cost, least-risk
21 resource identified through the RFP process and sited
22 within the Treasure Valley, but the project stalled when
23 developers were denied Conditional Use Permits - an
24 indicator of land use limitations that exist near the
25 Treasure Valley.
ELLSWORTH, DI 22
Idaho Power Company
1 Q. What limits the transmission capabilities to
2 serve incremental demand in the Treasure Valley?
3 A. The Treasure Valley is served primarily
4 through three transmission connections : (1) Midpoint West,
5 (2) the Hemingway 500/230-kV transmission station, and (3)
6 Brownlee East, which transmits power from the Pacific
7 Northwest and the Canyon Complex. I will first discuss
8 Midpoint West . Paths 16, 18, 19, 20 and the future Idaho-
9 Southern Nevada path all are, or will be, interconnected
10 to the Company' s transmission system east of the Treasure
11 Valley. System imports from the east and south, including
12 the 700 MW of future Four Corners and SWIP-North capacity
13 gained, as well as generation from existing resources,
14 must all cross the Midpoint West path to reach the
15 Treasure Valley load. Midpoint West is a path that is
16 already experiencing congestion.
17 Q. Has Idaho Power analyzed the remaining
18 Available Transmission Capacity ("ATC") on the Midpoint
19 West path to confirm it requires expansion?
20 A. Yes . Idaho Power has performed a simulation
21 analysis on the remaining ATC of the Midpoint West path
22 and determined that the additional 700 MW of import
23 capacity acquired has the potential to exceed the
24 remaining Midpoint West ATC. This ATC analysis, which
25 utilized the latest load forecast and simulated resource
ELLSWORTH, DI 23
Idaho Power Company
1 acquisitions from the 2025 IRP Preferred Portfolio, was
2 performed on an hourly basis by netting the expected load
3 and generation east of Midpoint and adding expected
4 imports flowing east-to-west across Midpoint West, over a
5 10-year period. Figure 2 below identifies the expected
6 Midpoint West ATC projection over the 10-year period. The
7 red dots indicate hours that transfers across Midpoint
8 West exceed the Total Transfer Capability ("TTC") of the
9 path and may cause facility overloads, whereas the blue
10 dots indicate hours the projected transfers are below the
11 Midpoint West TTC and are not expected to cause overloads .
12 Figure 2 . Projected Midpoint West ATC.
o
rood
im-
im
wo
0
svnv we IF WT
_y00 IRH
fd R R R r: fj
13 9tsrtme
14 The results of the ATC simulation indicate it is not
15 possible to utilize the full capacity of the Four Corners
16 and SWIP-North imports to serve load continually, and
17 often only a portion of the 700 MW could be imported with
18 some hours showing projected ATC dropping below negative
19 500 MW. The constrained hours primarily occur during
20 winter months when the simulation is heavily relying on
ELLSWORTH, DI 24
Idaho Power Company
1 Four Corners and SWIP-North imports for load service .
2 Segment E-8 however can help mitigate transmission
3 constraints by providing a parallel high-voltage path into
4 the Treasure Valley, reducing the burden on the Hemingway
5 500/230-kV transmission station and reducing the
6 congestion on the Midpoint West path.
7 Q. Did the Company analyze the ATC with the
8 availability of Gateway West Segment E-8?
9 A. Yes . Segment E-8 will unlock additional
10 internal east-to-west capacity across Midpoint West,
11 allowing for the Four Corners and SWIP-North transmission
12 imports to be fully utilized to serve system load, year-
13 round, without restriction. Figure 3 illustrates the same
14 Midpoint West path ATC analysis but includes import
15 capabilities on Segment E-8 with an estimated in-service
16 date of spring 2030 . Note, the analysis does not include
17 any potential future resources planned by the Company or
18 currently in the generator interconnection queue .
19 Figure 3 . Projected Midpoint West ATC with Segment E-8 .
CJMV i $
R R $
20
ELLSWORTH, DI 25
Idaho Power Company
1 The results of the ATC simulation illustrate that
2 following the addition of Segment E-8, there are no
3 overloads on the Midpoint West facilities projected in the
4 simulation timeframe . The results of the ATC simulation
5 analysis highlight that absent Segment E-8, hours of
6 constrained transmission on the Midpoint West path will
7 exist, limiting options for Idaho Power to cost-
8 effectively import energy to serve load and to utilize
9 allocated transmission capacity to the fullest extent .
10 Q. How does Segment E-8 increase the ATC across
11 the Midpoint West path?
12 A. As explained earlier, the Midpoint West path
13 consists of one 500-kV transmission line between the
14 Midpoint and Hemingway substations, three 230-kV
15 transmission lines between the Midpoint and Boise Bench
16 substations and two 138-kV transmission lines into the
17 Mountain Home area. Without Segment E-8, the loss of the
18 largest 500-kV transmission line causes flow to be
19 redistributed onto the smaller 230-kV and 138-kV Midpoint
20 West facilities which often cause projected system
21 overloads . Segment E-8 will provide a second parallel 500-
22 kV path for an incremental 2, 000 MW of capacity to flow
23 across Midpoint into the Treasure Valley. With two 500-kV
24 facilities in-service, an outage of either 500-kV line
25 redistributes flow primarily onto the other 500-kV
ELLSWORTH, DI 26
Idaho Power Company
1 facility rather than the smaller 230-kV and 138-kV lines,
2 significantly increasing the expected transfer capability,
3 and therefore ATC, of Midpoint West .
4 Q. What will limit the Company' s ability to bring
5 Pacific Northwest power west-to-east across Path 14 into
6 the Treasure Valley?
7 A. Idaho Power relies heavily on purchasing low-
8 cost power from the Pacific Northwest and transmitting it
9 west-to-east across Path 14 to the Company' s customers .
10 However, most of the Path 14 transmission capacity is
11 allocated, including the capacity gained by B2H. While a
12 planned 230-kV switchyard project at Pallette Junction
13 will potentially increase Path 14' s transmission capacity,
14 the next limiting element for west-to-east transmission
15 service is the overload of the Hemingway 500/230-kV
16 transformer. The current forecast of loads and transfers
17 indicates the Hemingway 500/230-kV transformer could
18 become overloaded during high-load conditions and
19 contingency events, therefore serving load with additional
20 imports from the west is not currently a viable solution.
21 Q. Will Segment E-8 of Gateway West prevent the
22 overload of the Hemingway 500/230-kV transformer?
23 A. Yes . Segment E-8 will mitigate overloads of
24 the Hemingway transformer by providing an additional 500-
25 kV path out of the Hemingway substation. In addition to
ELLSWORTH, DI 27
Idaho Power Company
1 benefiting Idaho Power by providing additional west-to-
2 east import capabilities to serve load, third parties may
3 utilize any available west-to-east transmission capacity.
4 Q. Are west-to-east transmission service requests
5 common?
6 A. Yes . Since 2020, Idaho Power has performed
7 nearly 50 system impact studies because of transmission
8 service requests received, totaling approximately 4, 000 MW
9 for Path 14 west-to-east. This resulted in four executed
10 transmission service agreements totaling 400 MW, all of
11 which require Segment E-8 to be in-service for
12 transmission service to commence . Transmission service
13 agreements benefit the Company' s retail customers as the
14 revenue received from transmission customers offsets
15 retail revenue requirements .
16 Q. How will Segment E-8 impact east-to-west
17 transmission capability between Idaho and the Pacific
18 Northwest?
19 A. Idaho Power expects Path 14 east-to-west
20 transmission capability will increase by approximately
21 1, 000 MW. The existing transmission system has only the
22 Midpoint to Hemingway 500-kV transmission line between the
23 Magic Valley and Treasure Valley, and west of Hemingway
24 there are both the Hemingway to Summer Lake and B2H 500-kV
25 lines . Therefore, Midpoint to Hemingway acts as a
ELLSWORTH, DI 28
Idaho Power Company
1 bottleneck for transmission flows . Segment E-8 alleviates
2 this constraint and allows for substantially increased
3 east-to-west power flow. Again, Path 14 is a valuable
4 transmission connection between two regions, and revenue
5 received from usage by transmission customers offsets
6 retail revenue requirements .
7 Q. Did the Company consider any alternatives to
8 the addition of Segment E-8?
9 A. Yes . Because Segment E-8 addresses multiple
10 transmission constraints, I will outline the alternatives
11 considered. First, absent Segment E-8, addressing the need
12 for transmission capacity between the Magic Valley and
13 Treasure Valley would require multiple 230-kV lines . There
14 are numerous reasons this approach is impractical,
15 including the following: (1) the capacity provided by a
16 230-kV line is typically less than a quarter of the
17 capacity of a 500-kV line, especially over long distances,
18 (2) multiple 230-kV lines means more land usage, i .e . ,
19 right-of-way, which could practically be optimized to
20 higher voltage lines, (3) lower voltage lines have much
21 higher electrical losses, (4) the Company has no
22 incremental permitted 230-kV line routes between the Magic
23 Valley and Treasure Valley, (5) 500-kV is more efficient
24 with a lower cost per MW than 230-kV, and (6) 500-kV has
25 numerous other ancillary benefits, such as Path 14
ELLSWORTH, DI 29
Idaho Power Company
I bidirectional uprates, among others discussed in this
2 testimony.
3 Second, absent Segment E-8 and the Mayfield 500-kV
4 substation, the Company would still need to address the
5 ability to transmit additional power into the Treasure
6 Valley. This would require the expansion of the Hemingway
7 substation, with the addition of a second 500/230-kV
8 transformer and routing additional 230-kV lines from
9 Hemingway into the Treasure Valley - which would require
10 routes that would extend through more populous Treasure
11 Valley areas . As a fully permitted project, in addition to
12 being cost-effective, the addition of Gateway West is a
13 more flexible option to increase transmission capacity
14 into the Treasure Valley.
15 Idaho Power' s ability to reliably serve its largest
16 load center, the Treasure Valley, depends on maintaining
17 sufficient east-to-west transmission capability across the
18 Midpoint West path. The Company has acquired an additional
19 700 MW of import capabilities to cost-effectively serve
20 Idaho Power customers that will also utilize the Midpoint
21 West path. Segment E-8 will directly resolve this emerging
22 constraint by adding a second 500-kV transmission line
23 between Midpoint and the Treasure Valley allowing the
24 Company to fully utilize its Four Corners and SWIP-North
25 import rights year-round, maintain reliable east-to-west
ELLSWORTH, DI 30
Idaho Power Company
1 flows, and ensure access to lower-cost market energy for
2 Idaho Power customers when available .
3 Interconnection of Resources with Segment E-8
4 Q. How does the addition of Segment E-8 support
5 the interconnection of future generation resources?
6 A. To understand the value Segment E-8 provides
7 through interconnection of future generation resources, I
8 will first explain the Generator Interconnection process
9 all new resources must follow to interconnect to Idaho
10 Power' s system. The process operates as an annual cluster
11 study whereby a developer submits its proposed generation
12 project during the Cluster Request Window and Idaho Power
13 studies all submitted projects together. Through this
14 process, the Company will identify any necessary Network
15 Upgrades for which the proposed projects share in the
16 costs .
17 The generator interconnection studies look to
18 ensure that all the resources can generate without
19 negatively impacting the existing system. When the
20 interconnection study identifies a violation, a new
21 Network Upgrade is proposed to resolve the violation.
22 Because of the large number of projects in any given
23 cluster study, the Network Upgrades that resolve the most
24 violations are prioritized so that the most resources are
25 interconnected as efficiently as possible .
ELLSWORTH, DI 31
Idaho Power Company
1 Q. Is Segment E-8 of Gateway West considered in
2 the interconnection studies?
3 A. Yes . Segment E-8 has been identified as an
4 optimal project as part of the generator interconnection
5 studies for several years as the project allows for the
6 existing 230-kV system between Midpoint and the Treasure
7 Valley to be repurposed. Today, two 230-kV lines run
8 directly from Midpoint to the Boise Bench substation.
9 These existing two lines are series compensated, meaning
10 capacitors have been added to reduce the line impedance
11 and increase transfer capacity, and are used to move power
12 directly between the Magic Valley and the Treasure Valley.
13 While beneficial to the system, when lines are series
14 compensated, it is difficult to split or reroute the lines
15 to accommodate the interconnection of new resources
16 without significantly decreasing the path rating for
17 Midpoint West. However, with the addition of Segment E-8,
18 these existing lines will no longer be a main source of
19 transmission service between the Magic Valley and the
20 Treasure Valley, allowing for the reduction or complete
21 removal of the series compensation from the 230-kV lines,
22 and the ability to interconnect new generation resources
23 with lower impact on the post-Segment E-8 Midpoint West
24 path rating.
25
ELLSWORTH, DI 32
Idaho Power Company
1 Q. Does Idaho Power have further evidence that
2 new generation resources are planned to interconnect with
3 the addition of Segment E-8?
4 A. Yes . Generator interconnection studies have
5 identified modifications to existing 230-kV transmission
6 infrastructure to aid in the interconnection of potential
7 resources that would not be possible without Segment E-8
8 due to their negative impact on transfer capability.
9 First, as shown in Figure 1, two of the 230-kV lines
10 currently used for transfer capacity between Midpoint and
11 Boise Bench will connect to the Mayfield substation. In
12 addition, the 500-kV sections of Segment E-8 between
13 Hemingway and Mayfield and Mayfield and Midpoint are
14 facilities that several currently queued interconnections
15 are contingent upon.
16 Q. Are there alternatives to interconnection
17 absent Segment E-8 of Gateway West?
18 A. Yes . Absent Segment E-8, to interconnect new
19 resources, multiple new long-distance 230-kV lines would
20 need to be built to yield capacity on par with the single
21 Segment E-8 but, as I discussed earlier in my testimony,
22 they come with associated burdens, i .e . , more land use,
23 less efficient, more costly, etc.
24 Q. Through the generator interconnection process,
25 has Idaho Power studied interconnection resources without
ELLSWORTH, DI 33
Idaho Power Company
1 Segment E-8?
2 A. Yes . Over 20 interconnections with a total
3 nameplate exceeding 5, 000 MW are currently contingent on
4 Segment E-8 . At the request of one interconnection
5 customer with a nameplate of 330 MW it was found that the
6 series compensation would have to be redone, at a cost of
7 approximately $50 million, and approximately 50 miles of
8 the existing 230-kV line would have to be rebuilt, at a
9 cost of an additional approximately $125 million, for
10 total costs estimated to be over $175 million, and this
11 did not fully address deliverability to the Treasure
12 Valley. With Segment E-8, these same projects could
13 interconnect with only the cost of the 230-kV substation.
14 Segment E-8 of Gateway West is a cost-effective addition
15 to facilitating the interconnection of generation
16 resources .
17 Added Operational Flexibility with Segment E-8
18 Q. Does the addition of Segment E-8 provide any
19 operational benefits?
20 A. Yes . As described earlier in my testimony,
21 Idaho Power' s Midpoint West path is currently congested
22 and any sustained outages on the path reduce the Company' s
23 ability to transmit generation to serve load. Following a
24 planned upgrade at the Midpoint substation, the pre-
25 Segment E-8 Midpoint West rating is expected to be 3, 350
ELLSWORTH, DI 34
Idaho Power Company
1 MW, with Idaho Power owning 1, 660 MW of that capacity.
2 Loss of the Midpoint to Hemingway 500-kV transmission line
3 causes flow to be redistributed to smaller 230-kV and 138-
4 kV Midpoint West facilities which result in system
5 overloads at the Midpoint 345/230-kV transformation point.
6 Because North American Electric Reliability Corporation
7 ("NERC") standard TOP-001 requires the Company operate the
8 system such that any system operating limits are not
9 violated, should the Midpoint to Hemingway 500-kV line be
10 out of service, Idaho Power must restrict actual flows
11 east-to-west on the Midpoint West path below 850 MW to
12 maintain compliance with this standard. This results in a
13 reduction of approximately 2, 500 MW of east-to-west
14 capacity across Idaho Power' s transmission system, with
15 810 MW of this loss allocated to Idaho Power and the
16 remainder allocated to PacifiCorp. To continue to serve
17 load on the east-to-west path, the Company must then
18 reduce transmission schedules pro-rata with other firm,
19 east-to-west reservations to accommodate the reduced
20 transmission capacity, which can make it challenging to
21 balance loads with reduced access to generation in the
22 east. PacifiCorp must also reduce its transmission
23 schedules by up to 1, 690 MW. Depending on system stress,
24 loss of Midpoint to Hemingway 500-kV line can be one of
25 the most severe outages on Idaho Power' s transmission
ELLSWORTH, DI 35
Idaho Power Company
1 system.
2 Q. What prevents the smaller 230-kV and 138-kV
3 Midpoint West facilities from handling the power transfer
4 levels during an outage?
5 A. Hemingway-Midpoint is the sole 500-kV facility
6 in Midpoint West and carries the majority of the east-to-
7 west transmission flow across Idaho Power' s system. The
8 parallel 345/230-kV transformers, and 230-kV and 138-kV
9 Midpoint West transmission lines are unable to handle
10 power transfer levels made possible by a 500-kV facility;
11 therefore, the outage of the Midpoint to Hemingway 500-kV
12 line results in a significant reduction in transmission
13 capacity.
14 Q. Does an outage on the Midpoint to Hemingway
15 500-kV line occur frequently?
16 A. The Midpoint to Hemingway 500-kV transmission
17 line is active due to its significant line length. In
18 2025, the Midpoint-Hemingway 500-kV line tripped
19 unexpectedly seven times and was de-energized twice for
20 maintenance and construction projects . However, with the
21 addition of Segment E-8, a second 500-kV path for
22 transfers between the Magic Valley and Treasure Valley
23 would be available . With two 500-kV facilities in service,
24 an outage of a single 500-kV line redistributes flow
25 primarily onto the other 500-kV facility and prevents
ELLSWORTH, DI 36
Idaho Power Company
1 overloads of the underlying 230-kV and 138-kV system. This
2 noticeably increases the expected transfer capability
3 under outage conditions, reducing the likelihood that
4 transmission related curtailments will be severe, and
5 allows Idaho Power to continue to serve customer load
6 effectively and economically.
7 Q. Does the addition of Segment E-8 provide any
8 additional operational benefits?
9 A. Yes . Once Segment E-8 has been placed in-
10 service, other than for the most extreme east-to-west
11 transfer conditions, the Company expects it will no longer
12 require the Midpoint-Hemingway-Summerlake remedial action
13 scheme ("RAS") . The Midpoint-Hemingway-Summer Lake RAS is
14 an automatic scheme designed to relieve overloads
15 experienced when either the Midpoint to Hemingway or
16 Hemingway to Summer Lake 500-kV lines are lost with heavy
17 east-to-west flows . The scheme consists of two systems,
18 RAS A and RAS B, which will bypass the Burns 500-kV series
19 capacitor, initiating a level 1 or level 2 trip signal to
20 trip generation on the eastern side of Idaho' s system at
21 the Bridger 345-kV substation. A level 1 signal curtails
22 the generation at Bridger by a minimum of 350 MW, and a
23 level 2 signal curtails the generation at Bridger by a
24 minimum of 700 MW. Curtailment of Idaho Power' s share of
25 the Bridger resource requires the Company to replace the
ELLSWORTH, DI 37
Idaho Power Company
1 lost capacity, either with market purchases or by
2 increasing internal generation, or worst-case scenario,
3 Idaho Power may be forced to shed customer load to restore
4 the system load and generation balance .
5 However, with the addition of Segment E-8, the
6 rating of Midpoint West will increase dramatically without
7 the need for the Midpoint-Hemingway-Summer Lake RAS .
8 Segment E-8 instead will create a parallel 500-kV pathway
9 to facilitate energy transfers and the RAS will be
10 disabled under normal operating conditions .
11 IV. CONCLUSION
12 Q. Please summarize your testimony.
13 A. The Gateway West project has been identified
14 in the Regional Transmission Plans since 2007, ultimately
15 identifying Segment E-8 of Gateway West as a key component
16 of the plan. As a result, Idaho Power modeled inclusion of
17 Gateway West as part of its IRP process, performing an
18 additional Gateway West analysis as part of the 2023 IRP
19 and subsequently refined in the 2025 IRP, resulting in the
20 recognition of Segment E-8 as a necessary transmission
21 investment providing an additional 2, 000 MW of transmission
22 capacity that will cost-effectively enable incremental
23 resource additions .
24 Idaho Power' s ability to reliably serve its largest
25 load center, in the Treasure Valley, depends on maintaining
ELLSWORTH, DI 38
Idaho Power Company
1 sufficient transmission capability, which is currently
2 constrained. To meet any growth on the system, Idaho Power
3 must either build new generation close to the Treasure
4 Valley or the Company must increase the transmission
5 capability into that region. It is infeasible from both a
6 permitting and land perspective to site the required
7 magnitude of resources in, or adjacent to, the Treasure
8 Valley. The addition of Segment E-8 will bolster the
9 Company' s transmission capability to support load growth,
10 increase bilateral connectivity between the Magic Valley
11 and Treasure Valley, and allow for the efficient
12 interconnection of new generation resources east of the
13 Treasure Valley. As a fully permitted project, the addition
14 of Gateway West is the most flexible and cost-effective
15 option to increase transmission capacity across southern
16 Idaho .
17 Q. Does this complete your testimony?
18 A. Yes, it does .
19
ELLSWORTH, DI 39
Idaho Power Company
1 DECLARATION OF JARED L. ELLSWORTH
2 I, Jared L. Ellsworth, declare under penalty of
3 perjury under the laws of the state of Idaho:
4 1 . My name is Jared L. Ellsworth. I am employed
5 by Idaho Power Company as the Transmission, Distribution &
6 Resource Planning Director for the Planning, Engineering &
7 Construction Department.
8 2 . On behalf of Idaho Power, I present this
9 pre-filed direct testimony in this matter.
10 3 . To the best of my knowledge, my pre-filed
11 direct testimony and Exhibit Nos . 1, 2 and 3 are true and
12 accurate.
13 I hereby declare that the above statement is true to
14 the best of my knowledge and belief, and that I understand
15 it is made for use as evidence before the Idaho Public
16 Utilities Commission and is subject to penalty for perjury.
17 SIGNED this 3rd day of April 2026, at Boise, Idaho.
18 C;
��✓
19 Signed:
20 Jared L. Ellsworth
21
ELLSWORTH, DI 40
Idaho Power Company
BEFORE THE
IDAHO PUBLIC UTILITIES COMMISSION
CASE NO. IPC-E-26-09
IDAHO POWER COMPANY
ELLSWORTH , DI
TESTIMONY
EXHIBIT NO. 1
The Gateway West Transmission Project
Salmon
Council ss
• Sheridan•
ascade E3
�Y
Weiser •Challis �'�`� Basin Gillett�
a Buffalo-
8
Payette •Dubois
pinned Idaho - ® �° Q Worland ,o
iy •Saint ro
Caldwell D F i', Rexburg Anthony
h BdSe
ailey Arco Rigby Drggs Thermopolis
HE INGWAY N Li Jackson
Fairtirltl Idaho ;
•Falls
Blackfoot WINDSTAR
'!1y=2• Gooding - — i 0 M I N G,,)�caaPer /�
MID Shoshone ,Pocatello Pmedale AD 11M
e BORAN 8 Soda -Lander .:JOHNSTONTwin Jerome Rupent !•.`.American Springs ie NST
Falls
Falls o
Burley POPULUSL"1 NEYIIARD °1
CEDAR
` HILL ,, 8 ' Par. ,, - SHIRLEY
Malad• Preaton AEOLU BASIN
City
JIM Rawlins
Aooreved Routes other Features d Kammerer BRIDGER
2013 Recortl of Decision A. Substations
- j`ANTICLINE i B
(ROD) Morley Nelson Snake Rivar
r_Segments 1-7 erN 10 If Money
of Prey NCA Green
201E Enn—mantel 8 R—r ES "' Laramie
Assessment(EA)Decision v•oa.rnw -
--
Atiemebvel �,,nwssn. Evanston
r•Segment 8 --
Segment 9
Exhibit No. 1
Case Nos. IPC-E-26-09&PAC-E-26-06
J. Ellsworth, IPC
Page 1 of 1
BEFORE THE
IDAHO PUBLIC UTILITIES COMMISSION
CASE NO. IPC-E-26-09
IDAHO POWER COMPANY
ELLSWORTH , DI
TESTIMONY
EXHIBIT NO. 2
Gateway West Segment E-8
proposedThe
Caldwell Management 3%US Bureau of Reclamation land,9%state land,and 28%
20 B O I S E
-of-way to cross federal land were granted in Rights
2private 018-Counties
Boise ,"rcrosseanyon, more, ng,Jerome, ,
Hailey
CANYO-NI I CAMAS
i I
Fairfield
MelbaE L M O R C -
�
I �
�+ A D A I ------J-- -----
Murphy .\, i L I N-C 0 L N
--------Mountain-Home j
I
GOODING j
. -\ i
26
Gooding , Shoshone
OWYHEE ^-� �j V\ I 93
L i I ..r
JeromeProposed Gateway West Segment E-8 J ER O M E
500 kV Transmission Line Project
1 30 _
MI Proposed Gateway West Segment E-8 National Park Service
TWIN FALLS Twin
Q Existing Substation US Forest Service Falls
0 Other Planned Substation State
US Bureau of Land Management I
Private or Other
US Bureau of Reclamation
US Department of Defense i 10 20 30 d0
(Ales
Exhibit No.2
Case Nos. IPC-E-26-09&PAC-E-26-06
J. Ellsworth, IPC
Page 1 of 1
BEFORE THE
IDAHO PUBLIC UTILITIES COMMISSION
CASE NO. IPC-E-26-09
IDAHO POWER COMPANY
ELLSWORTH , DI
TESTIMONY
EXHIBIT NO. 3
NorthernGrid 2024-2025 Regional Transmission Plan
2024-2025 Regional
Transmission Plan
Member-Driven
■ sebsrt—
Reglonal Tram-1-1—Plan
-- Cedar HIII-Populus
Hemngnay-Mldpa t*2 500 kV AC
MT Midpoint-Cedar Hill
P.Wl,n-Ant,0—
EaiWng Trsn"ission Linos(HIFLD)
2YJ 287kV
34S kV
5W W
IOW kV(DC)
ID �IMrinnGid
OR s......+Iem".V Galeaay S-11,
a,d 13a1—y W d Segm l D 1 are
Heminpkw nd drnded on Ilan dugram.0 Ivey are
WWipolm WY urdur uarbtl action
Popul l dlel
a
Cedar HIII ■-
Mles
_/l
NV UT -
CO
CA 4-
7/772025
Ora S__Hvn:elrra
AZ NM ww i.ro.Ia No aM:r.:i
NorthernG rid
Exhibit No.3
Case Nos. IPC-E-26-09&PAC-E-26-06
J. Ellsworth, IPC
Page 1 of 1