20251118Direct Matthew Suess.pdf

RECEIVED
November 18, 2025
IDAHO PUBLIC
BEFORE THE UTILITIES COMMISSION
IDAHO PUBLIC UTILITIES COMMISSION
IN THE MATTER OF IDAHO POWER )
COMPANY'S APPLICATION FOR ) CASE NO. IPC-E-25-16
AUTHORITY TO INCREASE ITS )
RATES AND CHARGES FOR )
ELECTRIC SERVICE IN THE STATE )
OF IDAHO )
DIRECT TESTIMONY OF MATTHEW SUESS
IN SUPPORT OF THE STIPULATION AND
SETTLEMENT
IDAHO PUBLIC UTILITIES COMMISSION
NOVEMBER 18, 2025

1 Q. Please state your name, business address, and
2 present position with the Idaho Public Utilities Commission
3 ("Commission") .
4 A. My name is Matthew Suess, and my business address
5 is 11331 West Chinden Boulevard, Building 8, Suite 201-A,
6 Boise, Idaho, 83714 . I am employed as an engineer for the
7 Commission Staff ("Staff") .
8 Q. Please describe your educational background and
9 professional experience .
10 A. I was hired by the Commission in 2022 . My
11 educational background and professional experience are
12 provided in more detail in Exhibit No . 103 .
13 Q. What is the purpose of your testimony in this
14 case?
15 A. The purpose of my testimony is to identify the
16 primary causes of the incremental revenue requirement
17 ("IRR") filed by Idaho Power Company ("Company") to
18 increase its rates and charges . It is important to
19 identify how much, if any, of the IRR is being caused by
20 growth from new large-load ("NLL") customers .
21 Q. How is your testimony organized?
22 A. My testimony is subdivided under the following
23 headings :
24 The Company' s Original IRR Page 2
25 Analysis of the EPIS Page 3
CASE NO. IPC-E-25-16 SUESS, M. (Stip) 1
11/18/25 COMMISSION STAFF

I The Types of New Load Growth Page 5
2 Primary Causes of the IRR Page 8
3 Conclusion Page 10
4 The Company' s Original IRR
5 Q. Please provide an overview of the Company' s
6 originally submitted IRR.
7 A. As filed, the Company' s system level IRR was an
8 increase of $206 million. ' For consistency, I will continue
9 using system level values versus jurisdictional values
10 throughout my testimony.
11 Q. What were the major contributing components to
12 this increase?
13 A. The single most significant component was a $95
14 million increase in the proposed return, 2 based on a $914
15 million increase to electric plant-in-service ("EPIS") . 3
16 A second large IRR component was a $30 million
17 increase to reduce the deferred balance for costs
18 associated with allowance for funds used during
19 construction to relicense the Hells Canyon Complex ("HCC
20 Relicensing AFUDC") . 4
21 A third large component was an $18 million
22 increase to levelize the recovery of Bridger coal plant
23
24 i Exhibit No. 28, cell J44.
2 $914M x 7.818% ROR x 1.334 net-to-gross tax multiplier.
25 3 Exhibit No. 28, cell J58 minus cell F58.
4 Exhibit No. 21 at 29.
CASE NO. IPC-E-25-16 SUESS, M. (Stip) 2
11/18/25 COMMISSION STAFF

I ("Bridger") retirement expenses . 5
2 The balance of the IRR comes from many other
3 components that are not large enough to be a major
4 contributing factor.
5 Q. Which of the components, if any, are increasing
6 due to baseline growth or NLL growth?
7 A. EPIS is the only component that has any growth-
8 related increase, and it is caused only by baseline growth.
9 Furthermore, the baseline growth contributions are less
10 than half of the incremental EPIS increase . I will
11 demonstrate both assertions later in my testimony. The HCC
12 Relicensing AFUDC, the Bridger retirement expenses, and the
13 other small factors are increasing for reasons other than
14 load growth.
15 Analysis of the EPIS
16 Q. Please provide an overview of the Company' s
17 originally submitted incremental EPIS increase .
18 A. The Company' s original filing claimed an
19 incremental EPIS increase of $914 million, which can be
20 divided into four categories .
21 The biggest category is the annualized balance
22 from 2024 EPIS, which is approximately $384 million. 6 This
23 EPIS was already declared prudent in the last rate case,
24
25 5 Noe Workpaper No. 32, cell G10.
6 Calculations from Exhibit No. 25, 28, and Noe Workpaper No. 13.
CASE NO. IPC-E-25-16 SUESS, M. (Stip) 3
11/18/25 COMMISSION STAFF

1 but $384 million was excluded from the 2024 EPIS due to
2 using the average of monthly averages ("AMA") method to
3 value rate base . The full annualized amount is
4 incorporated in the 2025 test year for this case .
5 The other three categories are different parts of
6 the 2025 EPIS : the forecasted AMA for "EPIS less than $2
7 million" is approximately $161 million; 7 the forecasted AMA
8 for "EPIS greater than $2 million" is $156 million; $ and the
9 estimated annualized balance for "EPIS greater than $2
10 million" is $213 million. 9 Together the four components sum
11 to $914 million. 10
12 Q. Was the $914 million increase in EPIS accepted as
13 part of the settlement?
14 A. No, portions were removed as part of the
15 settlement . Broadly speaking, the $213 million annualized
16 balance for 2025 EPIS was removed, and the other two 2025
17 components were reduced by a combined total of $21 million.
18 The approximate incremental EPIS included in the
19 settlement is $693 million, down from the original $914
20 million.
21 Q. How much of this $693 million in EPIS is in
22 support of baseline or NLL growth?
23
24 7 AMA calculations applied to Noe Workpaper No. 13.
8 Exhibit No. 25, cell H252.
25 9 Id. cell J252.
10$384 million + $161 million + $156 million + $213 million.
CASE NO. IPC-E-25-16 SUESS, M. (Stip) 4
11/18/25 COMMISSION STAFF

1 A. The annualized value of 2024 growth-driven EPIS
2 is approximately $156 million, " and the AMA value of 2025
3 growth-driven EPIS is $99 million. 12 Taken together, $255
4 million of the EPIS increase is growth-driven.
5 Using the same rate of return and net-to-gross
6 markup used by the Company in its application, one can
7 approximate that $255 million of growth-driven EPIS
8 increase would add $27 million to the IRR. 13
9 In other words, the maximum possible contribution
10 of growth-related projects to the IRR in this rate case is
11 $27 million, which is a relatively small portion of the
12 overall increase . Furthermore, the growth-related projects
13 can be differentiated between baseline growth and NLL
14 growth.
15 The Types of New Load Growth
16 Q. Please explain baseline growth and NLL growth and
17 discuss the implications .
18 A. The Company has experienced steady growth for
19 several years across multiple customer classes according to
20 its 2023 Integrated Resource Plan ("IRP") . 14 The Company
21 forecasts similar growth for many years to come . 15 This is
22 baseline growth.
23
11 Value estimated from 2024 Limited Issue Rate Case actuals.
24 12 AMA calculations applied to Noe Workpaper No. 13.
13 $255M x 7.818% ROR x 1.334 net-to-gross tax multiplier.
25 14 2023 IRP, Figure 4.1, at 43.
is 2023 IRP, Appendix C at 5.
CASE NO. IPC-E-25-16 SUESS, M. (Stip) 5
11/18/25 COMMISSION STAFF

1 However, beginning in 2026, and continuing
2 through at least 2030, The Company also forecasts extremely
3 rapid growth due to large customers via special contracts
4 (identified as "additional firm sales" in the IRP) . 16 This
5 is NLL growth.
6 Staff is concerned that the rapid expansion due
7 to NLL growth may incur unique costs in non-typical ways
8 and wants to ensure that those costs are identified and
9 properly allocated to the cost-causers .
10 Accordingly, it is important to distinguish
11 between baseline growth and NLL growth.
12 Q. How much of the $255 million growth-driven EPIS
13 is attributable to baseline growth, and how much to NLL
14 growth?
15 A. My analysis of various Company documents and
16 worksheets concludes that the entire $255 million is
17 attributable to baseline growth, and none of it is
18 attributable to NLL growth.
19 Q. Please explain how you reached this conclusion.
20 A. Three different lines of evidence support this
21 conclusion.
22 First, the individual projects that contributed
23 to the $255 million can all be traced to baseline growth.
24 The Company' s Response to Staff Request No . 36, Confidential
25
16 Id.
CASE NO. IPC-E-25-16 SUESS, M. (Stip) 6
11/18/25 COMMISSION STAFF

1 Attachment, provided a list of all projects greater than $2
2 million forecast to be placed in service in 2025 . The list
3 included descriptions of each project' s purpose and need,
4 so I was able to determine which projects were for baseline
5 growth, and that no projects were for NLL growth. I
6 repeated this same search in the 2024 rate case workpapers,
7 identifying which projects were growth-related and that no
8 projects were for NLL growth.
9 Second, the Company provided off-the-record
10 system capacity analysis that shows that the new resources
11 placed in service in 2024 and 2025 were necessary to ensure
12 sufficient capacity for baseline growth of existing load to
13 ensure reliability. Without those resources, the system
14 would have been capacity deficient . The data also shows
15 that the new resources placed in service in 2024 and 2025
16 did not have extra capacity that might be used to serve the
17 NLL growth scheduled to begin in 2026 .
18 Third, two Clean-Energy Your Way ("CEYW")
19 resources have recently come online to offset the
20 incremental energy loads of two NLL customers - Black Mesa
21 Solar in 202417 and Pleasant Valley Solar No . l in 2025 . 18 In
22 accordance with the CEYW special contracts, each resource
23 procurement was structured as a power purchase agreement
24
25 17 Case No. IPC-E-22-06.
18 Case No. IPC-E-22-29.
CASE NO. IPC-E-25-16 SUESS, M. (Stip) 7
11/18/25 COMMISSION STAFF

1 ("PPA") so the expenses are recorded to the Net Power
2 Supply Expense account19, not to EPIS . In other words, the
3 costs associated with these two projects are not part of
4 the $255 million growth-driven EPIS .
5 Primary Causes of the IRR
6 Q. If NLL growth is not causing the current IRR
7 increase, what is causing it?
8 A. I believe the IRR increase is being caused by a
9 combination of baseline load growth and other inflationary
10 pressures .
11 Q. Please discuss why you think baseline load growth
12 is a contributing factor.
13 A. The Company' s baseline load growth is significant
14 and persistent . The 2023 IRP 20-year load forecast is 1 . 1
15 percent annual growth for residential loads, 0 . 8 percent
16 for commercial loads, and 1 . 3 percent for industrial
17 loads . 20 This persistent dispersed growth has required -
18 and will require - continuous investment to upsize
19 distribution infrastructure, such as transformers,
20 switchgear, conductors, etc. Many of the 2025 growth-
21 related projects were for this purpose .
22 The persistent baseline growth has also required
23 several new resources to be added. For example, the
24
19 These PPA expenses are then passed through to the corresponding NLL
25 customers.
20 2023 IRP, Appendix A at 20-28.
CASE NO. IPC-E-25-16 SUESS, M. (Stip) 8
11/18/25 COMMISSION STAFF

1 majority of the $255 million of new growth EPIS was for a
2 handful of resources including the Franklin 60-megawatt
3 ("MW") Battery Energy Storage System ("BESS") , the
4 Hemingway 36 MW BESS Addition, the Kuna 150 MW BESS, and
5 the Happy Valley 80 MW BESS . The resources have been
6 consistently identified as general-purpose capacity
7 resources necessary to serve system load.
8 Q. Please discuss why you think inflation is a
9 contributing factor.
10 A. Since emerging from the 2020 Covid shutdown, the
11 Unites States has experienced steep and broad-based
12 inflation. The Consumer Price Index value for typical
13 goods and services has increased by 25 percent between
14 December 2020 and September 2025 (260 . 5 to 324 . 8) . 21
15 Within the electrical equipment sector, prices
16 have gone up even more steeply. For example, the Producer
17 Price Index value for Electrical Equipment Manufacturing
18 has increased by 51 percent between December 2020 and
19 August 2025 (154 . 1 to 232 . 7) . 22
20
21 21 U.S. Inflation Calculator, Consumer Price Index Data from 1913 to
2025, retrieved from
https://www.usinflationcalculator.com/inflation/consumer-price-index-
22 and-annual-percent-changes-from-1913-to-2008/, November 13, 2025.
23 22 U.S. Bureau of Labor Statistics, Producer Price Index by Industry:
Electrical Equipment Manufacturing [PCU3353133531] , retrieved from
24 FRED, Federal Reserve Bank of St. Louis;
https://fred.stlouisfed.org/series/PCU3353133531, November 13, 2025.
25
CASE NO. IPC-E-25-16 SUESS, M. (Stip) 9
11/18/25 COMMISSION STAFF

1 Given that a high percentage of the expenses in
2 electrical projects are for materials and the fact that
3 labor costs have increased, it is reasonable to conclude
4 that inflation is a significant contributing factor to the
5 IRR increase .
6 Conclusion
7 Q. Please summarize your testimony.
8 A. The IRR increase in this general rate case is
9 driven by many factors, including baseline load growth and
10 inflation. However, none of it should be attributed to NLL
11 growth.
12 Q. Does this conclude your testimony in this
13 proceeding?
14 A. Yes, it does .
15
16
17
18
19
20
21
22
23
24
25
CASE NO. IPC-E-25-16 SUESS, M. (Stip) 10
11/18/25 COMMISSION STAFF

Professional Qualifications
of
Matthew Suess
Engineer
Idaho Public Utilities Commission
EDUCATION AND CREDENTIALS
Mr. Suess graduated in 1989 from the United States Naval
Academy, receiving a Bachelor of Science degree in Electrical
Engineering. He graduated in 1990 from the Naval Nuclear Power
Propulsion program in Idaho Falls, Idaho . In 1996, he received a
Master of Science degree in Electrical Engineering from San Diego
State University. He obtained an Energy Certificate from the Naval
Postgraduate School in 2021 .
He was first licensed as a Professional Engineer for Electrical
Engineering in 1996 and has continuously maintained his license to
the present .
He completed the National Association of Regulatory Utility
Commissioners ("NARUC") Rate School in 2022 .
EXPERIENCE
Mr. Suess joined the Idaho Public Utilities Commission
("Commission") as a staff engineer in 2022 . His principal
responsibilities are to review applications from regulated utility
companies, analyze their requests, and prepare comments and
recommendations for Commission review.
Prior to joining the Commission, Mr. Suess was an active-duty
naval officer for 21 years and then served the Navy for ten more
years as a civilian employee . Of these combined 31 years in the
Navy, he served his first seven years as a nuclear-trained submarine
officer. The final 24 years he was an engineer assigned to manage
the construction, operation and maintenance of buildings and utility
systems on naval bases around the world.
Exhibit No . 103
Case No . IPC-E-25-16
M. Suess, Staff
11/18/25

CERTIFICATE OF SERVICE
I HEREBY CERTIFY THAT I HAVE THIS W'DAY OF NOVEMBER 2025,
SERVED THE FOREGOING DIRECT TESTIMONY OF MATTHEW SUESS IN
SUPPORT OF THE STIPULATION AND SETTLEMENT , IN CASE NO. IPC-E-25-16,
BY E-MAILING A COPY THEREOF, TO THE FOLLOWING:
DONOVAN E. WALKER TIMOTHY TATUM
MEGAN GOICOECHEA ALLEN CONNIE ASCHENBRENNER
IDAHO POWER COMPANY MATT LARKIN
PO BOX 70 1221 WEST IDAHO STREET
BOISE ID 83707-0070 P.O.BOX 70
E-MAIL: BOISE,ID 83707
dwalkergidahopower.com E-MAIL:
mfzoicoecheaallenkidahopower.com ttatumkidahopower.com
dockets(kidahopower.com caschenbrenner(kidahopower.com
mlarkin(kidahopower.com
CLEAN ENERGY OPPORTUNITIES: CLEAN ENERGY OPPORTUNITIES:
KELSEY JAE COURTNEY WHITE
920 N. CLOVER DRIVE MIKE HECKLER
BOISE, ID 83703 CLEAN ENERGY OPPORTUNITIES FOR
E-MAIL: kelsey(kkelseyjae.com IDAHO
3778 PLANTATION RIVER DR., STE 102
BOISE,ID 83703
EMAIL:
courtneykcleanenergyopportunities.com
mike c(r�,,cleanenergyopportunities.com
IIPA: IIPA:
ERIC L. OLSEN LANCE KAUFMAN,PH.D.
ECHO HAWK&OLSEN,PLLC 2623 NW BLUEBELL PLACE
P.O. BOX 6119 CORVALLIS, OR 97330
505 PERSHING AVE., STE. 100 E-MAIL: lance(kae.isg insi hg t.com
POCATELLO, ID 83205
E-MAIL: elokechohawk.com
BOISE CITY.• BOISE CITY.•
Ed Jewell Katie O'Neil
Deputy City Attorney Energy Program Manager
Boise City Attorney's Office Boise City Attorney's Office
P.O. Box 500 P.O. Box 500
Boise,ID 83701-0500 Boise, ID 83701-0500
eiewellkcityofboise.org koneil(kcityofboise.org
BoiseCityAttorney(kcityofboi se.org
CERTIFICATE OF SERVICE - PAGE 1

FEA: FEA:
Emily W. Medlyn Dwight Etheridge
Jelani A. Freeman Exeter Associates,Inc.
U.S. Department of Energy 10480 Little Patuxent Parkway, Ste. 300
1000 Independence Ave., S.W. Columbia,MD
Washington,D.C. 20585 detheridgekexeterassociates.com
emily.medlyn(khq.doe.gov
j elani.freeman(khq.doe.gov
ICIP:
PETER J. RICHARDSON
RICHARDSON ADAMS, PLLC
515 N. 27"' STREET
BOISE,ID 83702
E-MAIL: peter(cr�richardsonadams.com
MICRON: MaHydro:
Austin Rueschhoff C. Tom Arkoosh
Thorvald A.Nelson Nicholas J. Erekson
Austin W.Jensen Arkoosh Law Offices
Kristine A.K. Roach P.O. Box 2900
Holland&Hart,LLP Boise, ID 83701
555 17"' St., Ste. 3200 tom.arkooshkarkoosh.com
Denver,CO 80202 nick.erekson(karkoosh.com
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awj ensenkho llandhart.com
(cr�,�karoachhollandhart.com
ELECTRONIC SERVICE ONLY:
acleekhollandhart.com
tlfriel(khollandhart.com
Gannon, et al.,pro se: Korger:
John Gannon Kurt J.Boehm
johngannon200(kgmail.com Jody Keyle Cohn
Randy Morris occidentalpacifickhotmail.com Boeham,Kurtz&Lowry
Deborah Fease and Amy Lorrance 425 Walnut Street, Suite 2400
feased854(kgmail.com Cincinnati, OH 45202
kboelunkbkllawfirm.com
jkylercohn ckbkllawfirm.com
Northwest Energy Coalition (NWEC) Northwest Energy Coalition (NWEC)
Benjamin J. Otto Lauren McCloy
Attorney for NWEC Utility Regulatory Director
1407 W. Cottonwood Court lauren(knwenergy.org
Boise,ID 83702 Derek Goldman
benknwenergyy.org Policy Associate
derek(knwenergy.org
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