20240913PAC to Staff 241-245.pdf

RECEIVED
Friday, September 13, 2024
IDAHO PUBLIC
UTILITIES COMMISSION
_ ROCKY MOUNTAIN
POWER
A DIVISION OF PACIFICORP
1407 W North Temple, Suite 330
Salt Lake City, Utah 84116
September 12, 2024
Monica Barrios-Sanchez
Commission Secretary
Idaho Public Utilities Commission
11331 W. Chinden Blvd.
Bldg. 8, Ste. 201-A
Boise, ID 83714
monica.barriossanchez(a�puc.idaho.gov
SecretaU gpuc.idaho.gov
RE: ID PAC-E-24-04
IPUC Set 13 (241-249)
Please find enclosed Rocky Mountain Power's Responses to IPUC 13th Set Data Requests 241-
245. The remaining response will be provided under separate cover. Also provided are
Attachments IPUC 241 and 244. Confidential Attachment IPUC 243 is provided via BOX.
Confidential information is provided subject to protection under IDAPA 31.01.01.067 and
31.01.01.233, the Idaho Public Utilities Commission's Rules of Procedure No. 67—Information
Exempt from Public Review, and further subject to the non-disclosure agreement(NDA)
executed in this proceeding.
If you have any questions,please feel free to call me at(801) 220-2313.
Sincerely,
/s/
Mark Alder
Manager, Regulation
Enclosures
C.c.: Eric L. Olsen/IIPA eloAechohawk.com(C)
Lance Kaufman/IIPA lancegae_isg insi_h�(C)
Matthew Nykiel/ICL matthew.n, kielggmail.com
Brad Heusinkveld/ICL bheusinkveld(c-r�,idahoconservation.org
Thomas J. Budge/Bayer tina,racineolson.com(C)
Brian C. Collins/Bayer [e-mail]
Greg Meyer/Bayer gmey r(c-r�,consultbai.com
Kevin Higgins/Bayer [e-mail](C)
Neal Townsend/Bayer ntownsendgenergystrat.com(C)

Ronald L. Williams/PIIC rwilliamsghawleytroxell.com
Brandon Helgeson/PIIC bhel.eg son&hawleytroxell.com
Bradley Mullins/PIIC brmullins&mwanalytics.com
Val Steiner/PIIC val.steinerkitafos.com
Kyle Williams/PIIC williamsk(a),byui.edu

PAC-E-24-04/Rocky Mountain Power
September 12, 2024
IPUC Data Request 241
IPUC Data Request 241
In reference to the Company's response to Staff Production Request No. 82 and
Attachment IPUC 82-1,please provide an update to Attachment IPUC 82-1
using 20 years of daily heating degree day (HDD) and cooling degree day(CDD)
information from years 2004 through 2023 in a similar format as Attachment
IPUC 82-1. Also, please respond to the following:
(a) Please explain how the date range for daily HDD and CDD were determined
for Attachment IPUC 82-1.
(b) Please explain why Attachment IPUC 82-1 does not include the years 2022
and 2023 in the calculation.
Response to IPUC Data Request 241
The Company objects to this request on the grounds that it is unduly burdensome
and not reasonably calculated to produce admissible evidence in this proceeding.
Notwithstanding the foregoing objection the Company responds as follows:
Please refer to Attachment IPUC 241 which provides 20 years of daily heating
degree day(HDD) and cooling degree day(CDD) information for calendar years
2004 through 2023.
(a) Each year during the load forecast creation process, the 20-year normal
weather date range is rolled forward to include the most recent year of actual
weather available at the time of forecast creation. The normal weather period
used by the Company for the normalization of 2023 actuals was based on
normal weather used in the 2023 load forecast developed in the Spring 2022,
which relied on the 20-year normal weather range of 2002 through 2021.
(b) Please refer to the Company's response to subpart (a) above.
Recordholder: Lee Elder
Sponsor: Lee Elder

PAC-E-24-04/Rocky Mountain Power
September 12, 2024
IPUC Data Request 242
IPUC Data Request 242
In reference to the Company's response to Staff Production Request No. 82 and
Confidential Attachment IPUC 82-2, please provide an update to Confidential
Attachment IPUC 82-2 using input data from 1/1/2017 through 12/31/23 in a
similar format as Confidential Attachment IPUC 82-2. Also,please respond to the
following:
(a) Please explain how the date range for the input data was determined for
Confidential Attachment IPUC 82-2.
(b) Please explain why Confidential Attachment IPUC 82-2 does not include the
years 2021, 2022, and 2023 in the model.
(c) Please explain why variables that are not statistically significant(P-values
greater than .05%) were included in the weather spline models.
(d) Please explain why autoregressive terms are required in the weather spline
models.
(e) Please provide weather spline models and model output using input data from
1/1/2017 through 12/31/23 in a similar format as Confidential Attachment
IPUC 82-2 using only statistically significant(P-values greater than .05%)
variables and no autoregressive terms.
Response to IPUC Data Request 242
The Company objects to this request on the grounds that it is unduly burdensome,
not reasonably calculated to produce admissible evidence in the current
proceeding and the Company has not performed the requested analysis. Subject to
and without waiving the foregoing objections, PacifiCorp states as follows:
(a) Each year during the load forecast creation process, temperature spline date
range is rolled forward to include the most recent year of actuals at the time of
forecast creation. The period used by the Company for the spline models
developed in the Spring 2022 was based on the most recent five year period of
October 2017 through September 2021. These models are the basis of 2023
weather normalization for the Company's business purposes.
(b) Average daily kilowatt-hour(kWh)usage over the January 2021 through
September 2021 period is provided with the Company's response to IPUC
Data Request 82, specifically Confidential Attachment IPUC 82-2. The data
imported for the daily and holiday variables in the weather spline models
erroneously excluded the January 2021 through September 2021 period.
Incorporating January 2021 through September 2021 daily and holiday

PAC-E-24-04/Rocky Mountain Power
September 12, 2024
IPUC Data Request 242
variables would result in a de minimis 59 megawatt-hour(MWh) increase
(from -21,479 MWh to -21,420 MWh) in the weather adjustment. Data for
October 2021 through December 2023 was not available at the time of
weather spline creation.
(c) The Company's spline models include a standard set of daily, holiday and
monthly indicator variables. While some of these variables may become
insignificant in the model from time to time, the Company maintains these
variables for consistency across the set of spline models.
(d) The Company's spline models rely on time series data. A common issue with
models based on time series data is a lack of independence in the model
residuals which violates the assumptions of a linear regression model. The
standard method to correct this issue is the use of autoregressive terms which
restore the independence in the residuals creating a valid statistical model.
(e) The Company objects to this request on the grounds that it is unduly
burdensome and not reasonably calculated to produce admissible evidence in
the current proceeding.Notwithstanding the foregoing objection, the
Company responds as follows:
The Company has not performed the requested analysis.
Recordholder: Lee Elder
Sponsor: Lee Elder

PAC-E-24-04/Rocky Mountain Power
September 12, 2024
IPUC Data Request 243
IPUC Data Request 243
In reference to the Company's response to Staff Production Request No. 82 and
Attachment IPUC 82-3,please provide the models used to determine the
coefficients used to calculate the class level weather adjustments in Attachment
IPUC 82-3. For example, the residential calculation used coefficients of
.474035693 for the XHeat and .463221166 XCool variables. Also,please respond
to the following:
(a) Please explain how the date range for the input data was determined for this
model.
(b) If variables included in these models include variables that are not statistically
significant(P-values greater than .05%),please explain why the variables
were included in the models.
(c) If autoregressive terms are used in the models,please explain why
autoregressive terms were necessary.
(d) Please provide linear regression models and model output using the most
recent 20 years (2004-2023) for input data, only statistically significant(P-
values greater than .05%)variables, and no autoregressive terms.
(e) Please provide an update to Attachment IPUC 82-3 using the updated data
provided in Production Request No(s) 241 and 242 in a similar format as
Attachment IPUC 82-3.
Response to IPUC Data Request 243
Please refer to Confidential Attachment IPUC 243 which provides the class
models used to determine the coefficients used to calculate the class level weather
adjustments in the Company's response to IPUC Data Request 82, specifically
Attachment IPUC 82-3.
(a) Each year during the load forecast creation process, class model date range is
rolled forward to include the most recent year of actuals at the time of forecast
creation. The period used by the Company for the class models developed in
the Spring 2022 was based on the period of January 2000 through February
2022.
(b) The Company's class models include an intercept and monthly indicator
variables. While some of these variables may become insignificant in the
model from time-to-time, the intercept is required for model stability and the
monthly variables predict the monthly shape.

PAC-E-24-04/Rocky Mountain Power
September 12, 2024
IPUC Data Request 243
(c) Please refer to the Company's response to IPUC Data Request 242 subpart
(d).
(d) The Company objects to this request on the grounds that it is unduly
burdensome, and not reasonably calculated to produce admissible evidence in
the current proceeding.Notwithstanding the foregoing objection, the
Company responds as follows:
The Company has not performed the requested analysis.
(e) The Company objects to this request on the grounds that it is unduly
burdensome, and not reasonably calculated to produce admissible evidence in
the current proceeding.Notwithstanding the foregoing objection, the
Company responds as follows:
The Company has not performed the requested analysis.
Confidential information is provided subject to protection under IDAPA
31.01.01.067 and 31.01.01.233, the Idaho Public Utilities Commission's Rules of
Procedure No. 67—Information Exempt from Public Review, and further subject
to the Non-Disclosure Agreement(NDA) executed in this proceeding.
Recordholder: Lee Elder
Sponsor: Lee Elder

PAC-E-24-04/Rocky Mountain Power
September 12, 2024
IPUC Data Request 244
IPUC Data Request 244
In reference to the Company's response to Staff Production Request No. 82 and
Attachment IPUC 82-3,please provide the work papers showing the calculation
for the 2023 actual HDD_PerDay and CDD_PerDay values found on the
"Splines"tab of Attachment IPUC 82-3.
Response to IPUC Data Request 244
Please refer to Attachment IPUC 244.
Recordholder: Lee Elder
Sponsor: Lee Elder

PAC-E-24-04/Rocky Mountain Power
September 12, 2024
IPUC Data Request 245
IPUC Data Request 245
In reference to the Company's response to Staff Production Request No. 82 and
Attachment IPUC 82-4,please provide an update to Attachment IPUC 82-4 using
the updated Attachment IPUC 82-3 provided in response to Production Request
No. 243 part e.
Response to IPUC Data Request 245
The Company objects to this request on the grounds that it is unduly burdensome,
and not reasonably calculated to produce admissible evidence in the current
proceeding. Notwithstanding the foregoing objection, the Company responds as
follows:
The Company has not performed the requested analysis.
Recordholder: Lee Elder
Sponsor: Lee Elder

Joe Dallas (ISB# 10330)
Rocky Mountain Power
825 NE Multnomah, Suite 2000
Portland, OR 97232
Telephone: [phone]
Email:[e-mail]
Attorney for Rocky Mountain Power
BEFORE THE IDAHO PUBLIC UTILITIES COMMISSION
CASE NO. PAC-E-24-04
IN THE MATTER OF THE )
APPLICATION OF ROCKY ) ATTORNEY'S CERTIFICATE
MOUNTAIN POWER FOR ) CLAIM OF CONFIDENTIALITY
AUTHORITY TO INCREASE ITS ) RELATING TO DISCOVERY
RATES AND CHARGES IN IDAHO ) RESPONSES
AND APPROVAL OF PROPOSED )
ELECTRIC SERVICE SCHEDULES )
AND REGULATIONS )
I, Joe Dallas, represent Rocky Mountain Power in the above captioned matter. I am a
senior attorney for Rocky Mountain Power.
I make this certification and claim of confidentiality regarding the response to the attached
Idaho Public Utilities Commission Staff discovery request pursuant to IDAPA 31.01.01 because
Rocky Mountain Power, through its response, is disclosing certain information that is Confidential
and/or constitutes Trade Secrets as defined by Idaho Code Section 74-101, et seq. and 48-801 and
protected under IDAPA 31.01.01.067 and 31.01.01.233. Specifically, Rocky Mountain Power
asserts the Company's response IPUC Set 13 contains Company proprietary information that could
be used to its commercial disadvantage.
1

Rocky Mountain Power herein asserts that the aforementioned responses contain
confidential in that the information contains Company proprietary information.
I am of the opinion that this information is "Confidential," as defined by Idaho Code
Section 74-101, et seq. and 48-801, and should therefore be protected from public inspection,
examination and copying, and should be utilized only in accordance with the terms of the
Protective Agreement in this proceeding.
DATED this 12ffi day of September, 2024.
Respectfully submitted,
By
Joe Dallas
Senior Attorney
Rocky Mountain Power
2