20251202Staff Comments.pdf

RECEIVED
December 02, 2025
ADAM TRIPLETT IDAHO PUBLIC
DEPUTY ATTORNEY GENERAL UTILITIES COMMISSION
IDAHO PUBLIC UTILITIES COMMISSION
PO BOX 83720
BOISE, IDAHO 83702
[phone]
IDAHO BAR NO. 10221
Attorney for the Commission Staff
BEFORE THE IDAHO PUBLIC UTILITIES COMMISSION
IN THE MATTER OF AVISTA )
CORPORATION'S ANNUAL COMPLIANCE ) CASE NO. AVU-E-25-13
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 15, 2025, Avista Corporation("Company") filed a compliance filing
("Compliance Filing")requesting the Commission issue an order accepting its updated load
forecast, natural gas price forecast, and contracts used as inputs to calculate its incremental cost
Integrated Resource Plan-based("IRP-based") avoided cost rates, as required by Order Nos.
32697, 32802, and 35274.
STAFF ANALYSIS
Staff has reviewed the Compliance Filing and recommends that the Commission approve
the proposed load forecast and the proposed natural gas price forecast with an effective date of
January 1, 2026.
STAFF COMMENTS 1 DECEMBER 2, 2025

Load Forecast
The Company's most recent load forecast was developed on May 13, 2025. Compliance
Filing at 2. Staff compared the proposed load forecast to the approved load forecast in last year's
annual update case (Case No. AVU-E-24-10) in Figure No. 1 below and believes the proposed
load forecast is reasonable.
Figure No. 1: Load Forecast Comparison
Load Forecast Comparison
1600
1400
1200
1000
800
600
400
200
0
Lo r, oo m o N c.i m a Ln tp r, oo m o N r j m a Ln
N N N N M M M rn M M M M rn M � a a a �
O O O O O O O O O O O O O O O O O O O O
N N N N N N N N N N N N N N N N N fV N N
Approved Load Forecast in Case No.AVU-E-24-10
Proposed Load Forecast in Case No.AVU-E-25-13
The Company developed its medium-term forecast(Year 2026 through Year 2029)using
an econometrics-based method and developed its long-term forecast(Year 2030 through Year
2045)based on an end-use modeling method. Response to Staff Production Request No. 2 (a).
The combined methods were used to generate the load forecast in last year's annual update case.
Since last year's load forecast, the Company has not expected any significant changes in
customer growth (i.e. number of people or businesses moving into the service territory or large
customers being added to the system) or other forecasting assumptions such as electrification of
buildings or transportation. Response to Staff Production Request No. 2 (e). Staff believes the
proposed load forecast is reasonable.
Gas Price Forecast
The Company's gas price forecast is determined using a methodology that blends gas
price forecasts from the New York Mercantile Exchange ("NYMEX") forward market, the
STAFF COMMENTS 2 DECEMBER 2, 2025

Energy Information Administration's ("BIA")Annual Energy Outlook, and two consultant's
forecasts. Response to Staff Production Request No. 3. Table No. 1 below shows how the
methodology blends the different sources to determine the proposed forecast.
Table No. 1: Price Blend Methodology (2025 Natural Gas Integrated Resource Plan at 120)
Years Price Blend Methodology
2026 100% from forward prices only
2027 75% from forward prices and 25% from average of EIA and two consultant
forecasts
2028 50% from forward prices and 50% from average of EIA and two consultant
forecasts
2029 25% from forward prices and 75% from average of EIA and two consultant
forecasts
2030-2045 100% from average of EIA and two consultant forecasts
Because the IRP-based Public Utility Regulatory Policies Act of 1978 ("PURPA")
contracts have a maximum contract length of two years, Staff s analysis focused on the near term
of the proposed gas price forecast. Staff compared the proposed Henry Hub price forecast in this
case, the proposed Henry Hub price forecast in Case No. PAC-E-25-19, and the NYMEX
forward prices for Henry Hub published on October 15, 2025, provided in Response to Staff
Production Request No. 3 in Case No. IPC-E-25-33. See Figure No. 2 below. Because the near-
term forecasts from all three sources are similar to each other, Staff believes the proposed gas
forecast is reasonable.
STAFF COMMENTS 3 DECEMBER 2, 2025

Figure No. 2: Comparison of Gas Price Forecasts
Comparison of Gas Price Forecasts
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2.00
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tiro 1
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,ti0 ,ti0 ,ti0 ,ti0 ti0 ti0 ,ti0 f) ,ti0 ,LO ,ti0 ,ti0 ,0 ti0 ,ti0 ti0 ,ti0 ti0 ,ti0 ti0
Proposed Henry Hub Gas Forecast in Case No.AVU-E-25-13
Proposed Henry Hub Gas Forecast in Case No.PAC-E-25-19
ICE NYMEX Forward Market Prices on October 15,2025
Contract Changes
Since the filing of last year's annual update case, the Company has not signed any new
Power Purchase Agreements or new long-term contracts under PURPA. Therefore, there has not
been any contract changes since last year's compliance filing.
The Company states that the contract changes, together with the forecasts of load and gas
prices, are updated annually. Compliance Filing at 1. Staff would like to clarify that 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 RECOMMENDATION
Staff recommends that the Commission approve the proposed load forecast and the
proposed natural gas price forecast with an effective date of January 1, 2026.
'Order No.32697 required that long-term contracts be considered in the IRP methodology at such time as contracts
were signed and when they had terminated or expired. Later,Order No.33357 found the"signed contract"language
in Order No 32697 did not achieve its intended result and required utilities to create a queue to track the order in
which QF projects have entered negotiations with a utility.
STAFF COMMENTS 4 DECEMBER 2, 2025

Respectfully submitted this 2nd day of December 2025.
Adam Tripl t
Deputy Attorney General
Technical Staff. Yao Yin
I:\Utility\UMISC\COMMENTS\AVU-E-25-13 Comments.doex
STAFF COMMENTS 5 DECEMBER 2, 2025

CERTIFICATE OF SERVICE
I HEREBY CERTIFY THAT I HAVE THIS DAY OF DECEMBER 2025,
SERVED THE FOREGOING COMMENTS OF THE OMMISSION STAFF , IN CASE
NO. AVU-E-25-13, BY &MAILING A COPY THEREOF TO THE FOLLOWING:
DAVID J. MEYER SHAWN J. BONFIELD
VP & CHIEF COUNSEL SR. MGR., REGULATORY POLICY & STRATEGY
REGULATORY& GOV'T AFFAIRS AVISTA CORPORATION
AVISTA CORPORATION PO BOX 3727
PO BOX 3727 SPOKANE WA 99220-3727
SPOKANE WA 99220-3727 E-mail: shawn.bonfieldgavistacoEp.com
E-mail: david.me, er®,avistacorp.com
avistadocketsgavistacorp.com
PATRICIA JORDA , SECRETARY
CERTIFICATE OF SERVICE