20241203Staff Comments .pdf

RECEIVED
Tuesday, December 3, 2024 12:04:08 PM
IDAHO PUBLIC
UTILITIES COMMISSION
ADAM TRIPLETT
DEPUTY ATTORNEY GENERAL
IDAHO PUBLIC UTILITIES COMMISSION
PO BOX 83720
BOISE, IDAHO 83720-0074
[phone]
IDAHO BAR NO. 10221
Street Address for Express Mail:
11331 W CHINDEN BLVD, BLDG 8, SUITE 201-A
BOISE, ID 83714
Attorney for the Commission Staff
BEFORE THE IDAHO PUBLIC UTILITIES COMMISSION
IN THE MATTER OF AVISTA )
CORPORATION'S ANNUAL COMPLIANCE ) CASE NO. AVU-E-24-10
FILING TO UPDATE THE LOAD AND GAS )
FORECASTS IN THE INCREMENTAL COST )
INTEGRATED RESOURCE PLAN AVOIDED ) COMMENTS OF THE
COST MODEL TO BE USED FOR AVOIDED ) COMMISSION STAFF
COST CALCULATIONS )
COMMISSION STAFF ("STAFF") OF the Idaho Public Utilities Commission
("Commission"), by and through its Attorney of record, Adam Triplett, Deputy Attorney
General, submits the following comments.
BACKGROUND
On September 13, 2024, Avista Corporation("Company") filed a Compliance Filing (the
"Compliance Filing") requesting that the Commission issue an order accepting its updated load
forecast, natural gas price forecast, and contract information, which will be used as inputs to
calculate its Integrated Resource Plan based("IRP-based") avoided cost rates with an effective
date of January 1, 2025, in compliance with Order No. 35274. IRP-based avoided cost rates are
available to Qualifying Facilities that are above the resource-specific project eligibility cap for
STAFF COMMENTS 1 DECEMBER 3, 2024

published avoided cost rates under Idaho's implementation of the Public Utility Regulatory
Policies Act of 1978 ("PURPA").
STAFF ANALYSIS
Staff has reviewed the Compliance Filing and recommends the Commission approve the
following with an effective date of January 1, 2025:
1. The proposed load forecast for the period from Year 2026 through Year 2045;
2. The updated load forecast for Year 2025 contained in the Company's response to
Staff Production Request No. 1;
3. The proposed natural gas forecast for the period from Year 2026 through Year 2045;
and
4. The natural gas forecast for Year 2025 contained in the Company's response to Staff
Production Request No. 4.
Load Forecast
The Compliance Filing included an updated load forecast for the period from Year 2026
through Year 2045,but the Company subsequently provided an updated load forecast for Year
2025 through its response to Staff Production Request No. 1. Similar to the approved load
forecast in Case No. AVU-E-23-13, the proposed load forecast used two methods: (1)the
Traditional Supply and Demand Econometric Model Method(2025-2028) and(2) the End-Use
Forecasting Method(2029-2045). See Response to Staff Production Request No. 2. Because the
length of IRP-based PURPA contracts is up to two years, Staff s review focused on the near-term
load forecast up until 2028. After comparing the updated load forecast in this case and the
approved load forecast in Case No. AVU-E-23-13, Staff believes the updated load forecast is
reasonable.
Comparison to 2023 Annual Update
Staff compared the updated load forecast in this case and the approved load forecast in
Case No. AVU-E-23-13 and discovered the former is consistently higher than the latter. See
Figure No. 1. For the period from Year 2025 through Year 2028, the difference between the two
load forecasts is primarily due to (1) an incremental large customer load, (2) an improved
STAFF COMMENTS 2 DECEMBER 3, 2024

economic outlook, and(3) increased use per customer. See Supplemental Response to Staff
Production Request No. 7. Staff believes the justifications provided by the Company for the
increase in load are reasonable.
Load Forecast Comparison
1600
1400
1200
1000
5 800
600
400
200
0
202520262027202820292030203120322033203420352036203720382039204020412042204320442045
Updated Load Forecast in Case No.AVU-E-24-10 Approved Load Forecast in Case No.AVU-E-23-13
Figure No. 1: Load Forecast Comparison
Natural Gas Forecast
The Compliance Filing included a natural gas forecast for the period from Year 2026
through Year 2045, and the Company subsequently provided a natural gas forecast for Year 2025
through its response to Staff Production Request No. 4. The natural gas forecast provided in this
case is the same natural gas forecast approved in Case No. AVU-E-23-13. Staff believes it is
reasonable to use the proposed natural gas forecast for two reasons.
First, the proposed natural gas forecast is the most recent natural gas forecast available at
this time. See Response to Staff Production Request No. 5. In Case No. AVU-E-23-13, the
Company filed its original natural gas forecast on September 19, 2023, but the approved natural
gas forecast, which is also the proposed natural gas forecast in this case, was filed on December
20, 2023.
STAFF COMMENTS 3 DECEMBER 3, 2024

Second, the proposed Henry Hub forecast is similar to Rocky Mountain Power's Henry
Hub forecast, especially over the next few years, a critical timeframe for IRP-based PURPA
contracts. See Figure No. 2.
Gas Forecast Comparison
10
9
8
7
6
5
4
3
2
1
0
2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043
PAC's Henry Hub Forecast(PAC-E-24-12) Avista's Henry Hub Forecast(AVU-E-24-10)
Figure No. 2: Gas Forecast Comparison
Contract Updates
Contract updates are incorporated into the IRP model on a continuous basis,but the
annual filing provides an opportunity for the Commission to review and monitor these updates.
Staff believes the contract updates included in the Compliance Filing are correct, except for
Clearwater Paper's nameplate capacity. The nameplate capacity was incorrectly listed as 60
MW, and the correct nameplate capacity should be 132.2 MW. See Response to Staff Production
Request No. 6.
Despite the mistake, the Company clarified that power generation from Clearwater varies
from hour to hour and is correctly reflected in the IRP model. See Supplemental Response to
Staff Production Request No. 7. Staff believes it is reasonable to apply the hourly generation
shape in the IRP model to accurately reflect the expected generation amounts of Clearwater.
STAFF RECOMMENDATION
Staff recommends the Commission approve the following with an effective date of
January 1, 2025:
1. The proposed load forecast for the period from Year 2026 through Year 2045;
STAFF COMMENTS 4 DECEMBER 3, 2024

2. The updated load forecast for Year 2025 contained in the Company's response to
Staff Production Request No. 1;
3. The proposed natural gas forecast for the period from Year 2026 through Year 2045;
and
4. The natural gas forecast for Year 2025 contained in the Company's response to Staff
Production Request No. 4.
Respectfully submitted this Yd day of December 2024.
A am Tnplett
Deputy Attorney General
Technical Staff: Yao Yin
Seungjae Lee
I:\Utility\UMISC\COMMENTS\AVU-E-24-10 Comments.docx
STAFF COMMENTS 5 DECEMBER 3, 2024

CERTIFICATE OF SERVICE
I HEREBY CERTIFY THAT I HAVE THIS DAY OF DECEMBER 2024,
SERVED THE FOREGOING COMMENTS OF THE COMMISSION STAFF, IN CASE
NO. AVU-E-24-10, BY E-MAILING A COPY THEREOF TO THE FOLLOWING:
MICHAEL G ANDREA SHAWN J BONFIELD
SENIOR COUNSEL SR MGR REGULATORY POLICY
AVISTA CORPORATION AVISTA CORPORATION
PO BOX 3727 PO BOX 3727
SPOKANE WA 99220-3727 SPOKANE WA 99220-3727
E-mail: michael.andreagavistacorp.com E-mail: shawn.bonfieldgavistacorp.com
avistadocketsgavistacorp.com
PATRICIA JORDAN, SECRETARY
CERTIFICATE OF SERVICE