20241126PAC to Staff 5 - 1st Supplemental.pdf

RECEIVED
Tuesday, November 26, 2024
IDAHO PUBLIC
_ ROCKY MOUNTAIN UTILITIES COMMISSION
POWER
A DIVISION OF PACIFICORP
1407 W North Temple, Suite 330
Salt Lake City, Utah 84116
November 26, 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-24-12
IPUC Set 1 (1-5)
Please find enclosed Rocky Mountain Power's 1st Supplemental Response to IPUC 1st Set Data
Request 5.
If you have any questions, please feel free to call me at(801)220-2313.
Sincerely,
/s/
Mark Alder
Manager, Regulation
Enclosures

PAC-E-24-12/Rocky Mountain Power
November 26, 2024
IPUC Data Request 5 — 1 st Supplemental
IPUC Data Request 5
Please explain whether monthly Official Forward Price Curve (OFPC) is used in
the IRP model to determine IRP-based avoided cost rates. If hourly OFPC is used,
please explain how monthly OFPC is converted to hourly OFPC.
1't Supplemental Response to IPUC Data Request 5
Further to the Company's response to IPUC Data Request 5 dated November 21,
2024, the Company provides the following additional information:
The Company's monthly official forward price curve (OFPC) includes prices for
both electricity and natural gas. The Company's original response to IPUC Data
Request 5 addressed the hourly modeling of electricity prices within the
Integrated Resource Plan (IRP) model. Up to and including the Company's 2023
IRP, natural gas price modeling has reflected monthly natural gas pricing (one
price per natural gas market per month), though analysis of stochastic risks
conducted during the IRP reflects daily price volatility for natural gas (one price
per natural gas market per day). While stochastic risk analysis in the 2023 IRP
assessed a range of natural gas prices within a month, the expected value for each
day remained equal to the monthly average from the forward price curve. For the
2025 IRP, the Company is accounting for the daily price volatility within each
month, to help ensure that natural gas price movements reflect typical levels of
variation and correlation with peak loads and variable energy resource output,
rather than starting from the monthly average for each day. For a discussion of
these concepts, please refer to the presentation materials from the Company's
2025 IRP Public Input Meeting held on August 14, 2024 /August 15, 2024,
specifically slides 47 through 54. The presentation materials are publicly available
and can be accessed by using the following website link:
http s://www.pacificorp.com/content/dam/pcorp/documents/en/Pacificorp/energy
ntegrated-resource-plan/2025-irp/PacifiCorp 2025_IRP_PIM August_14-
15_2024.pdf
Because the changes in the modeling of natural gas prices in the 2025 IRP are
related to other changes in load and resource inputs which are not subject to
update between IRPs, the Company intends to continue using monthly natural gas
pricing (one price per natural gas market per month) for qualifying facility (QF)
pricing consistent with the methodology in the 2023 IRP until such time as all of
the modeling assumptions from the 2025 IRP are adopted.
Recordholder: Dan MacNeil
Sponsor: Dan MacNeil