20230906IPC to Staff 271-272_274-276.pdf

LISA D. NORDSTROM
Lead Counsel
[e-mail]

September 6, 2023

VIA ELECTRONIC FILING

Jan Noriyuki, Secretary
Idaho Public Utilities Commission
11331 W. Chinden Blvd., Bldg 8,
Suite 201-A (83714)
PO Box 83720
Boise, Idaho 83720-0074

Re: Case No. IPC-E-23-11
Idaho Power Company’s General Rate Case

Dear Ms. Noriyuki:

Enclosed for electronic filing, please find Idaho Power Company’s Response to
Request Nos. 271, 272, 274, 275, and 276 to the Fourteenth Production Request of the
Commission Staff to Idaho Power Company. Because of the volume of documentation
requested in the Fourteenth Production Request, the Commission Staff agreed it would
be acceptable for the Company to provide the responses in a minimum of two tranches.
The Company provided the first segment of responses and supporting documentation on
Friday, September 1, 2023. This filing represents the second and final segment of
responses and supporting documentation to the remainder requests.

Due to the collectively voluminous confidential and non-confidential information
provided in response to data requests in this case, the Company is posting the
attachments to these requests to the secure FTP site to allow parties to view the
requested information remotely unless otherwise noted in the response. Because certain
attachments contain confidential information, the FTP site is divided between confidential
and non-confidential information.

The login information for the non-confidential portion of the FTP site has been
provided to all parties that have intervened to date. The login information for the
confidential portion of the FTP site has been provided the parties that have executed the
Protective Agreement in this matter.

RECEIVED
2023 SEPTEMBER 6, 2023 4:36PM
IDAHO PUBLIC
UTILITIES COMMISSION
Jan Noriyuki, Secretary
September 6, 2023
Page 2

If you have any questions about the attached filing, please do not hesitate to contact me.

Very truly yours,

Lisa D. Nordstrom
LDN:sg
Enclosure

IDAHO POWER COMPANY’S RESPONSE TO THE FOURTEENTH PRODUCTION REQUEST OF THE
COMMISSION STAFF - 1
LISA D. NORDSTROM (ISB No. 5733)
DONOVAN E. WALKER (ISB No. 5921)
MEGAN GOICOECHEA ALLEN (ISB No. 7623)
Idaho Power Company
1221 West Idaho Street (83702)
P.O. Box 70
Boise, Idaho 83707
Telephone: [phone]
Facsimile: [phone]
[e-mail]
[e-mail]
[e-mail]

Attorneys for Idaho Power Company

BEFORE THE IDAHO PUBLIC UTILITIES COMMISSION

IN THE MATTER OF THE
APPLICATION OF IDAHO POWER
COMPANY FOR AUTHORITY TO
INCREASE ITS RATES AND CHARGES
FOR ELECTRIC SERVICE IN THE
STATE OF IDAHO AND FOR
ASSOCIATED REGULATORY
ACCOUNTING TREATMENT.
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CASE NO. IPC-E-23-11

IDAHO POWER COMPANY’S
RESPONSE TO THE
FOURTEENTH PRODUCTION
REQUEST OF THE COMMISSION
STAFF TO IDAHO POWER
COMPANY

COMES NOW, Idaho Power Company (“Idaho Power” or “Company”), and in
response to the Fourteenth Production Request of the Commission Staff (“Commission”
or “Staff”) dated August 25, 2023, herewith submits the following information:

IDAHO POWER COMPANY’S RESPONSE TO THE FOURTEENTH PRODUCTION REQUEST OF THE
COMMISSION STAFF - 2
REQUEST FOR PRODUCTION NO. 271: The Company's response to Staff
Production Request No. 139 (a) states that "[t]he Company reduced the AURORA-stated
zonal price by the weighted average wheeling rate in the model and the Company's loss
rate of 3.6 percent." Please respond to the following:
a. Please explain how the weighted average wheeling rate in the model is
determined; and
b. Please explain why the Company's loss rate, instead of inter-zonal loss
rate, is used.
RESPONSE TO REQUEST FOR PRODUCTION NO. 271: To first provide
context, the referenced Company Response to Staff’s Production Request No. 139(a)
refers to Company Witness Jessica Brady’s workpaper that details the calculation of
Account 447.050, which reflects revenues Idaho Power receives from third-party wheeling
customers who are paying Idaho Power to generate electricity to offset losses that are
incurred as the third-party wheels energy through the Company’s system. The referenced
quote from the Company’s Response to Staff’s Production Request No. 139(a) describes
how Idaho Power adjusted the output of AURORA to determine a marginal zonal price in
order to better match how these revenues are incurred in practice.
a. The weighted average wheeling rate was calculated using line capacity and the
associated Open Access Transmission Tariff (“OATT”) wheeling rate for all lines
that connect to Idaho Power’s zone.
b. Inter-zonal losses are not modeled in AURORA. Rather, loss rates are input for
each zone based on what is available in the open access same-time transmission
system (“OASIS”). Because loss rates vary for each zone, Idaho Power utilized its

IDAHO POWER COMPANY’S RESPONSE TO THE FOURTEENTH PRODUCTION REQUEST OF THE
COMMISSION STAFF - 3
loss rate of 3.6 percent as an estimate of the loss factor included in the AURORA-
stated zonal price.
The Company adjusted the AURORA-stated zonal price in order to
determine a zonal price that is reflective of just the marginal price within a zone,
thus better aligning the modeling output with the actual practice of utilizing Energy
Imbalance Market Load Aggregation Prices.
The response to this Request is sponsored by Jessi Brady, Regulatory Analyst,
Idaho Power Company.

IDAHO POWER COMPANY’S RESPONSE TO THE FOURTEENTH PRODUCTION REQUEST OF THE
COMMISSION STAFF - 4
REQUEST FOR PRODUCTION NO. 272: Brady's Workpaper No. 4 shows that
Transmission Expenses are calculated as the product of the Company's three-year
Average Wheeling Rate ($/MWh) and the AURORA generated Market Purchase Volume
(MWh). Please respond to the following:
a. Please explain why the wheeling rate in the AURORA model, which
determined the AURORA generated Market Purchase Volume (MWh), is not
used; and
b. Please provide the Transmission Expenses that are calculated using the
wheeling rate in the AURORA model, instead of the Company's three-year
Average Wheeling Rate ($/MWh).
RESPONSE TO REQUEST FOR PRODUCTION NO. 272:
a. The AURORA model output does not include the level of data needed to accurately
determine the amount of wheeling expenses associated with each transaction.
Therefore, the Company utilized a three-year average actual wheeling rate in the
calculation to better reflect the actual wheeling costs that would be incurred based
on modeled market transaction volumes.
The inability to track wheeling costs associated with individual transactions
within the AURORA model is largely due to the fact that if a purchase crosses more
than one zone, and therefore more than one line, the wheeling rates of each line
are added together to determine the total $/MWh wheeling rate for the transaction.
This prevents Idaho Power from simply applying an average of interzonal wheeling
rates for zones connected to Idaho Power within the model, because in both actual
practice and within the model, market transactions often require more than one

IDAHO POWER COMPANY’S RESPONSE TO THE FOURTEENTH PRODUCTION REQUEST OF THE
COMMISSION STAFF - 5
wheel. As a result, using a single wheeling rate would underestimate total wheeling
expenses included within the AURORA output.
To further complicate the output, the utilization of transmission lines within the
model could be due to Idaho Power-related transactions, but they could also result
from the model wheeling energy through Idaho Power’s system. This further
distorts the modeling output with regard to determining wheeling costs specifically
attributable to Idaho Power.
Given these modeling complications, Idaho Power determined that the most
accurate method for estimating wheeling costs was to apply the three-year
average of actual wheeling rates experienced by the Company to Idaho Power-
specific modeled transaction volumes.
b. If the Company used the same wheeling rate discussed in Request No. 271, total
wheeling expenses would be $4,729,824.81 (1,374,036.05 MWh x $3.44).
The response to this Request is sponsored by Jessi Brady, Regulatory Analyst,
Idaho Power Company

IDAHO POWER COMPANY’S RESPONSE TO THE FOURTEENTH PRODUCTION REQUEST OF THE
COMMISSION STAFF - 6
REQUEST FOR PRODUCTION NO. 274: Please explain whether the AURORA-
calculated market purchase expense (recorded in FERC Account 555) and surplus sales
revenue (recorded in FERC Account 447) net the expenses and revenues associated
with wheeling, and whether these expenses and revenues associated with wheeling are
recorded in other accounts.
RESPONSE TO REQUEST FOR PRODUCTION NO. 274: In preparation of this
response, the Company verified with Energy Exemplar (the vendor for the AURORA
software) that the AURORA-calculated market purchase expense does include wheeling
expenses, and the AURORA-calculated surplus sales revenue does not include wheeling
revenue.
However, when preparing this filing, through discussions with Energy Exemplar
the Company believed that the AURORA-output for both purchase expense and sales
revenue included wheeling. Because of this, the Company removed estimated wheeling
expenses from Federal Energy Regulatory Commission (“FERC”) Account 555 (as shown
on row 47 of Exhibit 30) and estimated wheeling revenues from FERC Account 447 (as
shown on row 81 of Exhibit 30).
The wheeling expenses removed from FERC Account 555 are reflected in the
Company’s 2023 test year in FERC Account 565, Third-Party Transmission. Wheeling
revenue included in the 2023 test year was forecasted outside of AURORA, and
therefore, the wheeling revenue removed from FERC Account 447 was not utilized in any
other account in the 2023 test year. The Company has included the table below, which
details how wheeling and losses are included (or not included) in the AURORA output
and in proposed base net power supply expenses in this case.

IDAHO POWER COMPANY’S RESPONSE TO THE FOURTEENTH PRODUCTION REQUEST OF THE
COMMISSION STAFF - 7
Topic Scenario AURORA Output FERC Account
Losses Expenses for losses on
market purchases Market Purchase Expense 555
Losses Revenue for losses on
market sales Surplus Sales Revenue 447
Losses
Revenue from third-
party transmission
losses
Calculated outside of AURORA
as described in response to
Request No. 139a
447.050
Wheeling Wheeling expenses on
market purchases Market Purchase Expense 565 (removed
from 555

As stated previously, the Company believed at the time of this filing that the
AURORA-calculated surplus sales revenue did include wheeling revenue. However, after
further discussions with Energy Exemplar, Idaho Power confirmed that the AURORA-
calculated surplus sales revenue does not include wheeling. This is specified in the table
below.
Topic Scenario AURORA Output FERC Account
Wheeling Wheeling revenue on
market sales Not Included N/A

Based on this revised understanding, the removal of $5,651,170.21 from the
AURORA-modeled results for Account 447 should not have occurred. However, it should
be noted that any change in the Company’s filed base net power supply expenses would
result in a corresponding offsetting change in the Power Cost Adjustment (“PCA”) rate
effective January 1, 2024.
The response to this Request is sponsored by Jessi Brady, Regulatory Analyst,
Idaho Power Company

IDAHO POWER COMPANY’S RESPONSE TO THE FOURTEENTH PRODUCTION REQUEST OF THE
COMMISSION STAFF - 8
REQUEST FOR PRODUCTION NO. 275: Please explain whether the base level
of market purchase expense contained in FERC Account 555 has already netted the
expenses associated with wheeling.
RESPONSE TO REQUEST FOR PRODUCTION NO. 275: While the AURORA
output for market purchase expense (FERC Account 555) does include wheeling
expenses, the Company has manually removed them as shown in Exhibit 30. As a result,
the filed base level of market purchase expense contained in FERC Account 555 does
not include wheeling expenses.
The response to this Request is sponsored by Jessi Brady, Regulatory Analyst,
Idaho Power Company

IDAHO POWER COMPANY’S RESPONSE TO THE FOURTEENTH PRODUCTION REQUEST OF THE
COMMISSION STAFF - 9
REQUEST FOR PRODUCTION NO. 276: In the example described in the
Company's response to Staff Production Request No. 151, please explain why Zone A's
purchase expense is not equal to Zone B's surplus sales revenue.
RESPONSE TO REQUEST FOR PRODUCTION NO. 276: After further review
and discussions with Energy Exemplar, the sales revenue value provided in response to
Production Request No. 151 was incorrect. In this example, Zone A is purchasing 100
MW from Zone B. The marginal resource price is $50.00. The wheeling rate on the line is
$3.00 and the loss factor is 0.01. The price that Zone A pays is ($50.00 + $3.00) / (1-0.01)
which is equal to $53.5353. Total market purchase expense recorded by Zone A is
$5,353.53 ($53.5353 x 100). Zone B is generating (100 MW / (1-0.01) which is equal to
101.0101. Total surplus sales revenue recorded by Zone B is $5,050.51 (($50.00) x
101.0101). As shown in this calculation and also described in the Company’s response
to Request No. 274, surplus sales revenue does not include wheeling.
The response to this Request is sponsored by Jessi Brady, Regulatory Analyst,
Idaho Power Company

IDAHO POWER COMPANY’S RESPONSE TO THE FOURTEENTH PRODUCTION REQUEST OF THE
COMMISSION STAFF - 10
DATED at Boise, Idaho, this 6th day of September 2023.

LISA D. NORDSTROM
Attorney for Idaho Power Company

DONOVAN E. WALKER
Attorney for Idaho Power Company

MEGAN GOICOECHEA ALLEN
Attorney for Idaho Power Company

IDAHO POWER COMPANY’S RESPONSE TO THE FOURTEENTH PRODUCTION REQUEST OF THE
COMMISSION STAFF - 11
CERTIFICATE OF SERVICE

I HEREBY CERTIFY that on the 6th day of September 2023, I served a true and
correct copy of Idaho Power Company’s Response to the Fourteenth Production Request
of the Commission Staff to Idaho Power Company upon the following named parties by
the method indicated below, and addressed to the following:

Commission Staff
Dayn Hardie
Chris Burdin
Deputy Attorney General
Idaho Public Utilities Commission
11331 W. Chinden Blvd., Bldg No. 8
Suite 201-A (83714)
PO Box 83720
Boise, ID 83720-0074

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Clean Energy Opportunities for Idaho
Kelsey Jae
Law for Conscious Leadership
920 N. Clover Dr.
Boise, ID 83703
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Courtney White
Mike Heckler
Clean Energy Opportunities for Idaho
3778 Plantation River Drive, Suite 102
Boise, ID 83703

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Industrial Customers of Idaho Power
Peter J. Richardson
Richardson Adams, PLLC
515 N. 27th Street
Boise, Idaho 83702

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IDAHO POWER COMPANY’S RESPONSE TO THE FOURTEENTH PRODUCTION REQUEST OF THE
COMMISSION STAFF - 12
Dr. Don Reading
280 Silverwood Way
Eagle, Idaho 83616

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Idaho Irrigation Pumpers Association,
Inc.
Eric L. Olsen
ECHO HAWK & OLSEN, PLLC
505 Pershing Avenue, Suite 100
P.O. Box 6119
Pocatello, Idaho 83205

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Lance Kaufman, Ph.D.
2623 NW Bluebell Place
Corvallis, OR 97330
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Micron Technology, Inc.
Austin Rueschhoff
Thorvald A. Nelson
Austin W. Jensen
Holland & Hart, LLP
555 Seventeenth Street, Suite 3200
Denver, Colorado 80202

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Jim Swier
Micron Technology, Inc.
8000 South Federal Way
Boise, Idaho 83707
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IDAHO POWER COMPANY’S RESPONSE TO THE FOURTEENTH PRODUCTION REQUEST OF THE
COMMISSION STAFF - 13
City of Boise
Ed Jewell
Darrell Early
Boise City Attorney’s Office
150 N. Capitol Blvd.
Boise, ID 83701
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Wil Gehl
Boise City Dept. of Public Works
150 N. Capitol Blvd.
P.O. Box 500
Boise, Idaho 83701-0500

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Idaho Conservation League
Marie Callaway Kellner
Idaho Conservation League
710 N. 6th Street
Boise, Idaho 83702

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Brad Heusinkveld
Idaho Conservation League
710 N. 6th Street
Boise, Idaho 83702
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IdaHydro
C. Tom Arkoosh
Arkoosh Law Offices
913 W. River Street, Suite 450
P.O. Box 2900
Boise, Idaho 83701

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Federal Executive Agencies
Peter Meier
Paige Anderson
Tanner Crowther
U.S. Department of Energy
1000 Independence Ave., S.W.
Washin ton, DC 20585
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IDAHO POWER COMPANY’S RESPONSE TO THE FOURTEENTH PRODUCTION REQUEST OF THE
COMMISSION STAFF - 14
Dwight Etheridge
Exeter Associates
5565 Sterrett Place, Suite 310
Columbia, MD 21044
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NW Energy Coalition
F. Diego Rivas
1101 8th Ave
Helena, MT 59601
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Walmart Inc.
Norman M. Semanko
Parsons Behle & Latimer
800 West Main Street, Suite 1300
Boise, Idaho 83702
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Steve W. Chriss
Director, Energy Services
Walmart Inc.
2608 Southeast J Street
Bentonville, Arkansas 72716
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Walmart Inc.
Justina A. Caviglia
Parsons Behle & Latimer
50 West Liberty Street, Suite 750
Reno, NV 89502
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Stacy Gust Regulatory Administrative
Assistant