20240913PAC to Staff 181-182 1st Supplemental Respons.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 13, 2024
Monica Barrios-Sanchez
Commission Secretary
Idaho Public Utilities Commission
11331 W. Chinden Blvd.
Bldg. 8, Ste. 201-A
Boise, ID 83714
monica.barrio ssanchez(apuc.Idaho.gov
S ecretarygpuc.idaho.gov
RE: ID PAC-E-24-04
IPUC Set 10 (175-204)
Please find enclosed Rocky Mountain Power's 1st Supplemental Responses to IPUC 101, Set
Data Requests 181-182.
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 elokechohawk.com(C)
Lance Kaufman/IIPA lance(&aegisinsi hg t.com(C)
Matthew Nykiel/ICL matthew.nykiel&gmail.com
Brad Heusinkveld/ICL bheusinkveld(&idahoconservation.org
Thomas J. Budge/Bayer tj racineolson.com(C)
Brian C. Collins/Bayer bcollins(cr�,consultbai.com
Greg Meyer/Bayer gmeyerkconsultbai.com
Kevin Higgins/Bayer khiggins(&energystrat.com(C)
Neal Townsend/Bayer ntownsend(a,energystrat.com (C)
Ronald L. Williams/PIIC rwilliams(&hawleytroxell.com
Brandon Helgeson/PIIC bhel eg sonkhawleytroxell.com
Bradley Mullins/PIIC brmullins&mwanal)tics.com
Val Steiner/PIIC val.steiner(&itafos.com
Kyle Williams/PIIC williamskkbyui.edu

PAC-E-24-04/Rocky Mountain Power
September 13, 2024
IPUC Data Request 181 — 1st Supplemental
IPUC Data Request 181
Please respond to the following regarding Tab "Emerg Purch+Trapp Sales" of
Excel File "ID GRC 2025 2023 Normalized Load.xlsm".
(a) Please define "Emergency Purchases".
(b) Please explain how the MWh amounts of Emergency Purchases from Line
171 to Line 218 are determined.
(c) Please explain how the costs of Emergency Purchases from Line 61 to Line
108 are determined.
(d) Please explain the cost impact of Emergency Purchases on Net Power Costs.
(e) If the cost impact is zero, please explain why it is zero. Also, if the cost
impact is zero, please confirm that the net expenses on Line 112 are not
included in the proposed Net Power Cost.
(f) Please explain what Column "Discount/Premium" represents.
(g) Please explain how "Discount/Premium" is used in the calculation of the costs
of Emergency Purchases.
1" Supplemental request received on September 2, 2024 from Idaho Public
Utilities Commission (IPUC) staff: Please explain why Emergency Purchases
are valued at 125% of market prices, instead of 100% of market prices. Also,
please explain why they are not valued at their dispatch costs.
1st Supplemental Response to IPUC Data Request 181
Further to the Company's response to IPUC Data Request 181 dated August 29,
2024 and to the Idaho Public Utilities Commission (IPUC) staff supplemental
request received on September 4, 2024, the Company provides additional
information responsive to subpart (c):
Based on available records, Emergency Purchases (Unspecified Purchased Power)
have been valued at 125 percent of market prices since the development of
Aurora's predecessor, the Generation and Regulation Initiative Decision Tools
(GRID), in 2001. This precedent has been carried through 23 years, and all
general rate cases (GRC), up to current day. The reasoning for the specific use of
the number 125 as compared to some other number has not yet been gleaned from
available records. However, based on first principles, since Unspecified
Purchased Power is a modeled resource of last resort, the price of its energy must
be greater than the price of energy across all power trading hubs (market) in any

PAC-E-24-04/Rocky Mountain Power
September 13, 2024
IPUC Data Request 181 — I"Supplemental
given period, else load would be served from Unspecified Purchased Power
modeled resources first, and then the market second.
Unspecified purchased power is a simulation—a modeling construct that does not
exist in reality - of regular firm purchased power bought at a market(power
trading hub), with the caveat that no modeled transmission is required to move the
purchased power to the point of delivery (POD). The test period short-term
transmission capacity modeled in the net power costs (NPC) forecast is based on a
four-year average of historical short-term transmission capacity. However, the
generation in the modeled NPC forecast is based on actual 2025 test period
expectations (example, includes upcoming new wind and solar resources) and the
load is based on 2023 weather adjusted actuals. This creates a mismatched
scenario wherein there can be more load or generation than there is transmission
to fully satisfy the needs of that load or generation. This mismatch occurs
because, as the system grows larger in both load and generation capacity, the
short-term transmission capacity required in 2025 would increase above the levels
calculated through a four-year average of historical short-term transmission
capacity which would represent transmission needed to serve lower levels of load
and generation capacity. The energy price for Unspecified Purchased Power
modeled resources are based on the market prices input into the model to reflect
the cost of wholesale purchased power expenses which it simulates.
Recordholder: Eshwar Vyakarna Raj shekar Rao
Sponsor: Ramon Mitchell

PAC-E-24-04/Rocky Mountain Power
September 13, 2024
IPUC Data Request 182 — 1st Supplemental
IPUC Data Request 182
Please respond to the following regarding Tab "Schedule 34"of Excel File
"ID GRC 2025 2023 Normalized Load.xlsm".
(a) Please explain what types of customers are under Utah's Schedule 34.
(b) Please explain how the MWh amounts in Column C through Column J are
determined.
(c) Please explain how the prices in Column R through Column U are
determined.
(d) Please explain whether the prices in Column R through Column U have been
approved by the Utah Commission.
(e) Please explain what Line 21 through Line 27 represent.
(f) Please explain how the values in Line 21 through Line 27 are determined.
1st Supplemental request received on September 2, 2024 from Idaho Public
Utilities Commission (IPUC) staff: Schedule 34. (a) Please explain whether the
power purchase expenses associated with Schedule 34 customers are based on the
excess energy that the Company purchases from the eligible resources under
Schedule 34. (b) If so, please explain how this rationale is reflected on Tab
"Schedule 34" of File "ID_GRC_2025_2023 Normalized Load.xlsm". (c)Please
define Line "Dollars Added"on Tab "Schedule 34" of File "ID GRC 2025 2023
Normalized Load.xlsm" and explain its function. (d)Please explain where the
power purchase expense of Schedule 34 ($41,924,762) is reflected on Tab"NPC
Summary" and Tab"NPC" of File "ID_GRC_2025_2023 Normalized
Load.xlsm".
1st Supplemental Response to IPUC Data Request 182
Further to the Company's response to IPUC Data Request 182 dated August 29,
2024 and to the Idaho Public Utilities Commission (IPUC) staff supplemental
request received on September 4, 2024, the Company provides additional
information:
Referencing confidential net power costs (NPC)report file "ID_GRC_2025_2023
Normalized Load.xlsm", the Company responds as follows:
(a) Yes. The purchase power expense associated with Schedule 34 customers'
resources is based on excess energy as noted in column K and the total costs
noted in column N. The final adjustment for Schedule 34 is noted on row 29

PAC-E-24-04/Rocky Mountain Power
September 13, 2024
IPUC Data Request 182 — I`Supplemental
which is negative in order to offset the purchased power expense of the
underlying resources.
(b) Please refer to the Company's response to subpart(a) above.
(c) "Dollar Added" refers to the net cost of purchasing excess energy from these
resources and the offset to remove the power purchase agreement (PPA) costs
associated with the Schedule 34 resources.
(d) On tab "NPC Summary", please refer to row 106, and on tab "NPC", please
refer to row 73.
Recordholder: Eshwar Vyakarna Rajshekar Rao
Sponsor: Ramon Mitchell