20241015AVU to Staff 1-6.pdf

RECEIVED
AVISTA CORPORATION Tuesday, October 15, 2024
IDAHO PUBLIC
RESPONSE TO REQUEST FOR INFORMATION UTILITIES COMMISSION
JURISDICTION: IDAHO DATE PREPARED: 10/15/2024
CASE NO: AVU-E-24-10 WITNESS: N/A
REQUESTER: Staff RESPONDER: James Gall
TYPE: Production Request DEPARTMENT: Energy Resources
REQUEST NO.: Staff-001 TELEPHONE: [phone]
REQUEST:
Please provide the value of Year 2025 in the energy load forecast and explain why it was not
provided in the Company's Compliance Filing.
RESPONSE:
The following is the 2025 load forecast in aMW:
Month System Load WA Load ID Load
January 1,411 886 525
February 1,286 805 480
March 1,177 734 443
April 1,096 682 414
May 1,039 647 392
June 1,086 681 404
July 1,175 735 440
August 1,169 741 428
September 1,026 649 377
October 1,062 667 395
November 1,230 772 458
December 1,371 858 512
Annual Average 1,177 738 439
The 2025 load forecast was not provided in the Company's Compliance Filing because the
compliance load forecast was derived from the IRP which has a planning period of 2026-2045.

AVISTA CORPORATION
RESPONSE TO REQUEST FOR INFORMATION
JURISDICTION: IDAHO DATE PREPARED: 10/15/2024
CASE NO: AVU-E-24-10 WITNESS: N/A
REQUESTER: Staff RESPONDER: James Gall
TYPE: Production Request DEPARTMENT: Energy Resources
REQUEST NO.: Staff-002 TELEPHONE: [phone]
REQUEST:
In Case No. AVU-E-23-13, the approved load forecast used two forecasting methods. For the
period from 2024 through 2028,the Company utilized traditional supply and demand econometric
models. For the period from 2029 through 2045, the Company used end-use forecasting methods.
Please explain whether the Company uses the same methodology to determine the proposed
energy load forecast. If not, please explain the methodology the Company used to determine the
proposed energy load forecast in this case.
RESPONSE:
In Case No. AVU-E-24-10, Avista's proposed energy forecast utilized traditional supply and
demand econometric models through 2028. For the period from 2029 through 2045,the Company
used end-use forecasting methods.

AVISTA CORPORATION
RESPONSE TO REQUEST FOR INFORMATION
JURISDICTION: IDAHO DATE PREPARED: 10/15/2024
CASE NO: AVU-E-24-10 WITNESS: N/A
REQUESTER: Staff RESPONDER: James Gall
TYPE: Production Request DEPARTMENT: Energy Resources
REQUEST NO.: Staff-003 TELEPHONE: [phone]
REQUEST:
Figure No. 1 below compared the proposed load forecast in this case and the approved load
forecast in Case No. AVU-E-23-13. Please explain why the proposed load forecast in this case is
consistently higher than the approved load forecast in Case No. A VU-E-23-13.
Figure No. 1: Load Forecast Comparison
Load Forecast Comparison
Load Forecast Comparison
1600
1400
1200
1000
800
600
400
200
0
lD I- 00 QI O -4 N M t? U1 �D f- 00 0) O N M e U1
N N N fV M M M Cn ^I M M M M1 In � � � qT d �
O O O O O O O O O O O O O O O O O O O O
N N PV fV N N N N N fV N N N PV fV N N N fV N
-Proposed Load Forecast in Case No.AVU-E-24-10
Approved Load Forecast in Case No. AVU-E-23-13
RESPONSE:
The proposed load forecast in this case is consistently higher due to several factors. As described
in Staff Request-002 a new methodology (end use) was utilized for the period 2029 to 2045, a
significant industrial customer was added since Case No. AVU-E-23-13, new EV and customer
generation forecast was utilized, and the economic factors between load forecasts are always
subject to change.

AVISTA CORPORATION
RESPONSE TO REQUEST FOR INFORMATION
JURISDICTION: IDAHO DATE PREPARED: 10/15/2024
CASE NO: AVU-E-24-10 WITNESS: N/A
REQUESTER: Staff RESPONDER: James Gall
TYPE: Production Request DEPARTMENT: Energy Resources
REQUEST NO.: Staff-004 TELEPHONE: [phone]
REQUEST:
Please provide the value of Year 2025 in the natural gas price forecast and explain why it was not
provided in the Company's Compliance Filing.
RESPONSE:
The nominal$per MMBtu natural gas price forecast for Year 2025 at Henry Hub and Stanfield are
$3.51 and $3.17, respectively. Forecasted monthly prices for Year 2025 through 2045 at Henry
Hub and Stanfield are included in Staff_PR_004 Attachment A CONFIDENTIAL_10-15-24. The
rationale for not providing a value for the Year 2025 in Avista's previous filing is due to the
alignment of natural gas prices used for Avista's 2025 Electric IRP,which begins in the year 2026
and continues through the year 2045.

AVISTA CORPORATION
RESPONSE TO REQUEST FOR INFORMATION
JURISDICTION: IDAHO DATE PREPARED: 10/15/2024
CASE NO: AVU-E-24-10 WITNESS: N/A
REQUESTER: Staff RESPONDER: James Gall
TYPE: Production Request DEPARTMENT: Energy Resources
REQUEST NO.: Staff-005 TELEPHONE: [phone]
REQUEST:
The proposed natural gas price forecast in this case is the same as the approved natural gas price
forecast in Case No. AVU-E-23-13. Please explain why the Company did not file an updated
natural gas price forecast and provide justification as to why it is reasonable to use the same natural
gas price forecast in this case.
RESPONSE:
The Company's original filing on September 19, 2023, in Case No. AVU-E-23-13 included the
natural gas forecast from the 2023 Natural Gas IRP, which was the current price forecast being
used by the Company at that time.An update was provided in Case No. AVU-E-23-13 on
December 20, 2023, because of the updated load forecast that was then available due to the
Company's work with AEG on developing a new end use based forecast. The new natural gas
price forecast developed for the 2025 IRP was also available at that time, so the Company included
it in the December 2023 update to provide the Commission with the most up-to-date information
available at that time.
Since the new natural gas price forecast for the 2025 IRP was submitted in Case No.
AVU-E-23-13, there is not an updated or newer natural gas price forecast to submit at this time.
The new load forecast from AEG provided in December 2023 causing last year's filing to take
longer than it normally would and allowed the Company to submit the newer gas price forecast.

AVISTA CORPORATION
RESPONSE TO REQUEST FOR INFORMATION
JURISDICTION: IDAHO DATE PREPARED: 10/15/2024
CASE NO: AVU-E-24-10 WITNESS: N/A
REQUESTER: Staff RESPONDER: James Gall
TYPE: Production Request DEPARTMENT: Energy Resources
REQUEST NO.: Staff-006 TELEPHONE: [phone]
REQUEST:
The confidential attachment of the Compliance Filing listed the nameplate capacity of Clearwater
Paper as 60 MW. However, Response to Staff Production Request No. 2 in Case No.
AVU-E-23-15 states that Clearwater's nameplate is 132.2 MW. Please reconcile the two numbers
and explain the cause for the difference.
RESPONSE:
In reference to the confidential attachment of the compliance filing, the 60 MW value was labeled
as the"nameplate value"within the context of the amount available to Avista as part of its PURPA
agreement. However, the overall nameplate value of the generation facility is 132.2 MW.