20260306Application.pdf

' 11
Avista Corp. RECEIVED
1411 East Mission P.O. Box 3727 MARCH 6, 2026
Spokane,Washington 99220-0500 AVU_E_26_02 IDAHO PUBLIC
Telephone [phone] UTILITIES COMMISSION
Toll Free 800-727-9170
March 6,2026
State of Idaho
Idaho Public Utilities Commission
11331 W. Chinden Blvd
Bldg 8, Suite 201-A
Boise,Idaho 83714
Case No.AVU-E-26-
I.P.U.C.No.28—Electric Service
Dear Commission Secretary:
The Company has attached for electronic filing with the Commission the following revised tariff sheets:
Twelfth Revision Sheet 51B canceling Supplemental Eleventh Revision Sheet 51B
Twenty-Eighth Revision Sheet 51E canceling Supplemental Twenty-Seventh Revision Sheet 51E
Twenty-Seventh Revision Sheet 51F canceling Supplemental Twenty-Sixth Revision Sheet 51F
Twenty Eighth Revision Sheet 51G canceling Supplemental Twenty-Seventh Revision Sheet 51G
Twenty-Sixth Revision Sheet 51H canceling Supplemental Twenty-Fifth Revision Sheet 51H
Thirteenth Revision Sheet 51J canceling Supplemental Twelfth Revision Sheet 51J
Twenty-Seventh Revision Sheet 51N canceling Supplemental Twenty-Sixty Revision Sheet 51N
Twenty-Eight Revision Sheet 510 canceling Supplemental Twenty-Seventh Sheet 510
The Company requests that the proposed tariff sheets be made effective May 15, 2026. These tariff sheets reflect
the Company's annual electric Line Extension filing. Detailed information related to the Company's request is
included in the attached Application and supporting workpapers.
The Company will issue a notice to its effected customers through a letter the week of April,6 2026. A copy of the
letter has been included in the Company's filing.
If you have any questions regarding this filing,please contact Athena Allen at(509)495-8325 or Joe Miller at(509)
495-4546.
Sincerely,
Is/Joe Miller
Joe Miller
Sr Manager of Rates and Tariffs

I ANNIGLOGOVAC
2 COUNSEL, LEGAL DEPARTMENT
3 AVISTA CORPORATION
4 1411 E. MISSION AVENUE
5 P. O. BOX 3727
6 SPOKANE, WASHINGTON 99220
7 PHONE: [phone]
8 EMAIL: anni.glo og vac(&avistacorp.com
9
10 BEFORE THE IDAHO PUBLIC UTILITIES COMMISSION
11 IN THE MATTER OF THE ELECTRIC )
12 LINE EXTENSION SCHEDULE 51 ) CASE NO. AVU-E-26-
13 ANNUAL RATE ADJUSTMENT FILING ) APPLICATION OF AVISTA
14 OF AVISTA CORPORATION ) CORPORATION
15
16 I. INTRODUCTION
17 In accordance with Idaho Code §61-502 and RP 052, Avista Corporation, doing
18 business as Avista Utilities (hereinafter "Avista" or "Company"), at 1411 East Mission
19 Avenue, Spokane,Washington,respectfully makes application to the Idaho Public Utilities
20 Commission("Commission")for an order approving the update in costs and administrative
21 changes to the Company's Electric Line Extension Schedule 51. The Company has
22 requested a May 15, 2026 effective date.
23 The Company requests that this filing be processed under the Commission's
24 Modified Procedure Rules (RP 201-204) through the use of written comments.
25 Communications in reference to this Application should be addressed to:
26 Anni Glogovac Patrick Ehrbar
27 Counsel for Regulatory Affairs Director of Regulatory Affairs
28 Avista Corporation Avista Corporation
29 P. O. Box 3727 P. O. Box 3727
30 1411 E. Mission Avenue, MSC 33 1411 E.Mission Avenue,MSC 27
31 Spokane, Washington 99220 Spokane, Washington 99220
32 Telephone: [phone] Telephone: [phone]
33 E-mail: anni.glo og vackavistacorp.com E-mail: patrick.ehrbargavistacorp.com
AVISTA'S ANNUAL ELECTRIC LINE EXTENSION FILING PAGE 1

I II. BACKGROUND
2 The Company's present Schedule 51 electric line extension tariff incorporates the
3 principle of average costing for electrical facilities commonly used in extending service.
4 The tariff sets forth "Basic and Exceptional Costs", which are costs based on recent
5 average actual costs for facilities such as transformers and conduit which are used
6 consistently for electric line extensions. The Basic and Exceptional Costs have a fixed
7 and variable component,with the variable component stated on a cost-per-foot basis. The
8 average costing principle incorporated in the Company's tariff has worked well and the
9 Company is not proposing to change the conceptual structure of the tariff.
10 In Commission Order No. 35757, the Commission ordered that future filings shall
11 clearly identify the details requested by Commission Staff(Staff) in their comments. In
12 particular Staff stated:
13 Staff recommends that the Company clearly identify the hours, materials,
14 and vehicle support it assumed for each type of line extension work, it
15 identify any changes from the previous year, and it provide evidence and
16 justification for the changes. Specifically, Staff recommends that the
17 Company provide actual work order examples for each type of line extension
18 work to provide confirmation of the standard estimates.
19
20 In compliance with the Commission Order, the Company has included additional
21 workpapers that detail the hours, materials, and vehicle support for each job, as well as
22 actual work order estimates for each job type.Detailed below are the Company's proposed
23 changes to Schedule 51 and included with this filing are workpapers which provide
24 support for the proposed changes.
AVISTA'S ANNUAL ELECTRIC LINE EXTENSION FILING PAGE 2

1 III. CONSTRUCTION ALLOWANCES
2 In this filing, the Company has updated the allowances applicable to new
3 residential, commercial and industrial customers. For purposes of calculating the revised
4 allowances,the Company is continuing to utilize an embedded-cost methodology approach
5 that is designed to ensure that investment in distribution/terminal facilities for each new
6 customer will be similar to the embedded costs of the same facilities reflected in base rates.
7 Any costs in excess of the allowance would be paid by the new customer as a Contribution
8 in Aid of Construction. The Company utilized its Cost of Service study from its most
9 recently concluded general rate case filing (AVU-E-25-01), updated for the base rates
10 approved in the Settlement Agreement and approved in Order No. 36741 effective
11 September 1, 2025, as the basis of the embedded cost calculation. Below is a summary of
12 the proposed allowance changes:
13 Service Schedule Existing Proposed
Schedule 1 Individual Customer(per unit) $ 2,545 $ 2,755
14 Schedule 1 Duplex(per unit) $ 2,035 $ 2,205
15 Schedule 1 Multiplex(per unit) $ 1,530 $ 1,655
Schedule 11/12 (per kWh) $ 0.19912 $ 0.21041
16 Schedule 21/22 (per kWh) $ 0.18388 $ 0.20083
Schedule 31/32 (per kWh) $ 0.32929 $ 0.35568
17
18 The Company has provided workpapers that provide the inputs and calculation of the
19 allowances.
20
21 IV. AVERAGE COSTS
22 The Distribution Engineering Department at Avista is primarily tasked with the
23 development and maintenance of the Company's Construction & Material Standards.
AVISTA'S ANNUAL ELECTRIC LINE EXTENSION FILING PAGE 3

I Periodically, Distribution Engineering will update the Construction & Material Standards
2 in order to comply with the National Electric Safety Code ("NESC"). These Construction
3 & Material Standards are reflective of the NESC's most recent code revisions. The
4 standard designs in this filing have not changed and are consistent with those reflected in
5 this filing.
6 As detailed on proposed tariff sheets 5 1 M and 51N, the Company is proposing to
7 update the primary, secondary, service and transformer average costs. Below is a
8 summary of the cost changes:
9 Present Proposed
Overhead Primary Circuit:
10 Fixed Cost $ 5,536 $ 5,952
Variable Cost $ 11.20 $ 12.04
11
Underground Primary Circuit
12 Fixed Costs $ 2,583 $ 2,754
Variable Costs $ 13.55 $ 14.31
13
Underground Secondary Circuit
14 Fixed Costs $ 647 $ 688
Variable Costs $ 12.75 $ 13.18
15
Overhead Secondary Circuit
16 Fixed Costs $ 2,279 $ 2,466
17
Overhead Service Circuit $ 5.06 $ 5.56
18 Underground Service Circuit $ 10.29 $ 10.78
19 Overhead Transformer $ 5,308 $ 5,222
20 Padmount Transformer $ 10,003 $ 9,134
21 The primary drivers of the slight increase contributing to the overall costs above are
22 related to higher overheads and vehicle costs.Higher maintenance and repair expenses for
23 our fleet vehicles and year-over-year higher fuel costs are driving the higher vehicle costs.
AVISTA'S ANNUAL ELECTRIC LINE EXTENSION FILING PAGE 4

I Rising labor and labor benefit costs are driving higher overheads costs.
2 Residential development costs, updated for the most current Construction &
3 Material Standards and average 2025 construction costs, are detailed below:
4 Residential Developments
Present Proposed
5 Total Cost per Lot $ 3,849 $ 3,818
6 Less:Service Cost $ 516 $ 541
Developer Responsibility $ 3,333 $ 3,277
7 Developer Refundable Payment $ 2,545 $ 2,755
8 Builder Non-Refundable Payment $ 1,304 $ 1,063
9 Allowance $ 2,545 $ 2,755
10 V. ADMINISTRATIVE CHANGES
11 Presently, tariff sheet 51 G states, "A Developer who pays the extension cost
12 described in 4.b.1) may apply for a refund annually for each permanent Customer
13 connected within the development during the first five years from the start of construction
14 after the extension is completed". For clarification purposes "after the extension is
15 completed"is being removed from the tariff verbiage to make clear the five-year look back
16 begins with the start of construction.
17
18 VI. COMMUNICATIONS AND SERVICE OF APPLICATION
19 In conformance with RP 125, this Application will be brought to the attention of
20 the Company's affected customers. Consistent with past practice,during the week of April
21 6, 2026, the Company will send a letter to those developers and builders that may be
22 affected by the proposed changes to inform them of the Company's request.
AVISTA'S ANNUAL ELECTRIC LINE EXTENSION FILING PAGE 5

I VII. REQUEST FOR RELIEF
2 The Company requests that the Commission issue an order approving the update in
3 costs to Schedule 51 to become effective May 15, 2026. The Company requests that the
4 matter be processed under the Commission's Modified Procedure rules through the use of
5 written comments.
6 Dated at Spokane, Washington this 6th day of March 2026.
7 AVISTA CORPORATION
8
9 BY Is/Patrick Ehrbar
10 Patrick D. Ehrbar
11 Director of Regulatory Affairs
AVISTA'S ANNUAL ELECTRIC LINE EXTENSION FILING PAGE 6