202507312025 Brandon Workpapers.pdf

CASE NO. AVU-E-25-07
2025 Idaho PCA Filing
Brandon Workpapers
Brandon, Di 2
Avista Corporation

Exhibit AMB-1
AVISTA UTILITIES
IDAHO ELECTRIC
IMPACT OF PROPOSED SCHEDULE 66 PCA CHANGE
PROPOSED RATE TO BE EFFECTIVE OCTOBER 1,2025
(000s of Dollars)
(000s of kWh) Total Billed Percent
Revenue Proposed change
Line Type of Schedule Forecasted at Present Sch.66 on Billed
No. Service Number Kilowatt-hours Rates Change Revenue
(a) (b) (c)(1) (d) (e) (f)
1 Residential 1 1,345,606 $ 165,358 $ (740) -0.4%
2 General Service 11,12 923,919 $ 90,280 $ (508) -0.6%
3 Large General Service 21,22 133,466 $ 18,739 $ (73) -0.4%
4 Extra Large General Service 25 349,435 $ 22,327 $ (192) -0.9%
5 Clearwater 25P 368,629 $ 36,136 $ (203) -0.6%
6 Pumping Service 31,32 62,677 $ 7,577 $ (34) -0.4%
7 Street&Area Lights 41-49 9,772 $ 4,530 $ (5) -0.1%
8 Total 3,193,504 $ 344,947 $ (1,755) -0.5%
check -0.5%
9 Proposed rate $ (0.00301) $ (9,611)
10 Present rate(AVU-E-24-07,Order No.36339) $ (0.00246) $ (7,855)
11 Rate Change $ (0.00055) $ (1,756)
Proposed rate
12 Total Amortization and Deferral Balance including interest thru 9/30/25 $ (9,560)
13 Conversion factor(Case No.AVU-E-23-01: Per Final Stipulation&Settlement) 0.995661
14 Revenue Requirement (9,602)
15 kWh's from above 3,193,504
16 Proposed rate: $ (0.00301)
(1) Source: Calendar Load forecast for the twelve month period October 1,2025-September 30,2026
AVU-E-25-07 2025 Brandon Workpapers
Exhibit AMB-1 Page 1 of 6

Avista Corporation PCA -1
July 2024 through June 2025
IPUC Deferral Analysis
AVU-E-21-03 A AVU-E-23-01 Jul-24 thru
Deferral for 2024-25 Deferral Period JulJul24 Aug-24 Sep-2 Oct-24 Nov-24 Dec-24 Jan25 Feb-25 Mar-25 Aor-25 May-25 Jun-25 Jun-25
BASE RATE RECOVERY-LOAD CHANGE ADJUSTMENT
Idaho Actual Sales MWh 269,577 247,042 240,747 226,201 270,409 301,614 321,041 296,404 266,258 237,389 234,353 245,300 3,156,335
Idaho Base Sales MWh 256,211 254,893 218,497 235,421 260,464 297,899 304,450 275,917 276,088 250,222 227,023 225,845 3,082,930
Actual-Base Sales MWh 13,366 (7,851) 22,250 (9,220) 9,945 3,715 16,591 20,487 (9,830) (12,833) 7,330 19,455 73,405
LCAR $/MWh 24.41 24.41 24.50 24.50 24.50 24.50 24.50 24.50 24.50 24.50 24.50 24.50
Retail Revenue Adjustment-Under(+)/Over(-) (326,264) 191,643 (545,125) 225,890 (243,653) (91,018) (406,480) (501,932) 240,835 314,409 (179,585) (476,648) (1,797,928)
Base-to-Actual Percent Difference % 5.22% -3.08% 10.18% -3.92% 3.82% 1.25%1 5.45% 7.43% -3.56% -5.13% 3.23% 8.61% 2.38%
NET POWER SUPPLY EXPENSE
Actual Expense
555 Purchased Power $ 17,316,022 18,293,008 16,497,925 17,121,209 14,985,892 14,421,668 14,649,944 22,918,792 17,154,312 15,506,870 16,498,614 17,744,546 203,108,802
447 Sales for Resale $ (16,273,979) (13,264,153) (21,742,218) (16,458,393) (14,517,331) (14,588,182) (15,815,928) (17,283,171) (18,540,183) (16,913,483) (14,491,131) (16,307,443) (196,195,595)
501 Thermal Fuel $ 3,353,469 3,973,429 4,211,263 4,013,855 3,724,975 3,702,900 3,455,873 4,522,795 3,752,557 1,697,225 1,525,413 2,568,207 40,501,961
547 CT Fuel $ 7,487,946 7,787,680 7,985,983 6,729,712 9,740,078 12,068,628 13,795,379 12,944,613 10,184,136 5,401,423 3,985,276 8,335,950 106,446,704
456 Transmission Revenue $ (3,554,846) (3,160,779) (2,942,698) (3,149,533) (3,353,636) (3,350,095) (2,968,699) (2,980,575) (2,877,392) (2,606,548) (2,690,461) (2,446,343) (36,081,605)
565 Transmission Expense $ 1,676,118 1,848,334 1,780,711 2,773,036 2,197,137 2,227,626 2,251,109 2,251,996 2,656,824 2,476,343 2,399,160 2,395,608 26,934,002
537 MT.Invasive Species Expense $ 64,722 64,722 64,722 64,722 64,722 64,722 64,722 64,722 64,722 64,722 64,722 64,722 776,664
557 Expense Broker Fees $ 26,310 36,359 7,121 212,811 31,825 10,435 7,057 8,599 53,596 57,166 69,241 3,779 524,299
557 Resource Optimization $ (86,401) 145,222 53,125) (65,882) 1,107,449 688,935 210,603 (101,488) 458,090 (359,215) (146,870) (41,017) 1,756,301
Adjusted Actual Net Expense $ 10,009,261 15,723,822 5,809,694 11,241,537 13,981,111 15,246,637 15,650,060 22,346,283 12,906,662 5,324,503 7,213,964 12,318,009 147,771,533
Idaho Allocation Factor $ 34.47% 34.47% 34.47% 34.47% 34.47% 34.47% 34.47% 34.47% 34.47% 34.47% 34.47% 34.47%
Idaho Actual Net Expense $ 3,450,192 5,420,001 2,002,598 3,874,958 4,819,289 5,255,517 5,394,576 7,702,764 4,448,926 1,835,356 2,486,654 4,246,018 50,936,949
Authorized Net Expense
555 Purchased Power $ 5,937,659 5,836,088 5,942,565 6,194,512 6,489,810 6,556,792 7,435,932 7,069,211 7,433,801 5,672,869 5,579,483 5,419,545 75,558,267
447 Sales for Resale $ (9,557,120) (4,493,194) (7,072,562) (3,997,529) (2,672,014) (4,453,080) (2,316,991) (1,936,564) (2,540,468) (4,230,873) (3,489,856) (5,862,698) (52,622,949)
501 Thermal Fuel $ 2,879,162 3,146,005 3,033,757 2,874,156 2,395,831 3,087,726 3,151,777 2,749,966 2,896,333 2,060,445 1,526,412 1,782,225 31,583,795
547 CT Fuel $ 6,693,265 7,977,571 8,729,385 8,223,214 8,133,493 10,790,239 8,942,104 7,474,530 5,068,911 4,095,763 2,284,385 3,117,887 81,530,747
456 Transmission Revenue $ (2,267,860) (2,209,469) (1,714,509) (1,711,129) (1,937,530) (2,146,621) (1,634,727) (1,811,669) (1,891,560) (1,715,927) (2,123,305) (2,306,697) (23,471,003)
565 Transmission Expense $ 1,439,897 1,439,897 1,439,897 1,439,897 1,439,897 1,439,897 1,439,897 1,439,897 1,439,897 1,439,897 1,439,897 1,439,897 17,278,764
90%Palouse Wind and Rattlesnake Flats $ 2,442,750 2,442,750 2,442,750 2,442,750 2,442,750 2,442,750 2,442,750 2,442,750 2,442,750 2,442,750 2,442,750 2,442,750 29,313,000
Remove Columbia Basin Hydro Transmission Project(embedd $ (83,917) (83,917) (83,917) (83,917) (83,917) (83,917) (83,917) (83,917) (83,917) (83,917) (83,917) (83,917) (1,007,004)
Gas Liquids Revenue-456018 $ (524,310) (514,471) (290,007) (311,801) (548,421) (265,977) (633,351) (664,038) (880,329) (385,474) (657,028) (615,703) (6,290,910)
Montana Invasive Species Expense $ 134,167 134,167 134,167 134,167 134,167 134,167 134,167 134,167 134,167 134,167 134,167 134,167 1,610,004
Settlement Adjustments $ 52,636 52,636 52,636 52,636 52,636 52,636 52,636 52,636 52,636 52,636 52,636 52,636 631,632
Authorized Net Expense $ 7,146,329 13,728,063 12,614,162 15,246,956 15,846,702 17,554,612 18,930,277 16,866,969 14,072,221 9,482,336 7,105,624 5,520,092 154,114,343
Idaho Allocation Factor $ 34.47% 34.47% 34.47% 34.47% 34.47% 34.47% 34.47% 34.47% 34.47% 34.47% 34.47% 34.47%
Idaho Authorized Net Expense $ 2,463,340 4,732,063 4,348,102 5,255,626 5,462,358 6,051,075 6,525,266 5,814,044 4,850,695 3,268,561 2,449,309 1,902,776 53,123,215
RENEWABLE ENERGY CREDIT REVENUE
Actual REC Revenue $ (852,390) (766,566) (205,290) (336,186) (324,450) (346,014) (900) 0 44,535 0 0 0 (2,787,261)
Authorized REC Revenue $ 0 0 0 0 0 0 0 0 0 0 0 0 0
Actual-Authorized REC Revenue $ (852,390) (766,566) (205,290) (336,186) (324,450) (346,014) (900) 0 44,535 0 0 0 (2,787,261)
Idaho Allocation Factor $ 34.47% 34.47% 34.47% 34.47% 34.47% 34.47% 34.47% 34.47% 34.47% 34.47% 34.47% 34.47%
Actual-Authorized Idaho REC Revenue $ (293,819) (264,235) (70,763) (115,883) (111,838) (119,271) (310) 0 15,351 0 0 0 (960,768)
COST RECOVERY SUBJECT TO SHARING
Actual-Authorized Net Expense(Idaho share) $ 986,852 687,938 (2,345,504) (1,380,668) (643,069) (795,558) (1,130,690) 1,888,720 (401,769) (1,433,205) 37,345 2,343,242 (2,186,366)
Retail Revenue Adjustment $ (326,264) 191,643 (545,125) 225,890 (243,653) (91,018) (406,480) (501,932) 240,835 314,409 (179,585) (476,648) (1,797,928)
REC Revenue $ (293,819) (264,235) (70,763) (115,883) (111,838) (119,271) (310) 0 15,351 0 0 - (960,768)
456030 ED ID-Sch 25P Transmission $ 14,850 8,219 13,283 13,910 14,570 13,877 14,308 15,434 15,400 15,400 14,850 14,850 168,951
456380 ED ID-Sch 25P REC Revenue $ (30,647) (42,596) (83,330) (79,820) (91,349) (83,549) (84,633) (107,275) (89,397) (88,295) (99,866) (96,205) 976,962)
Sch 25P Net Cost (15,797) (34,377) (70,047) (65,910) (76,779) (69,672) (70,325) (91,841) (73,997) (72,895) (85,016) (81,355) (808,011)
Total Cost(Subject to Sharing) $ 350,972 580,969 (3,031,439) (1,336,571) (1,075,339) (1,075,519) (1,607,805) 1,294,947 (219,580) (1,191,691) (227,256) 1,785,239 (5,753,073)
Sharing Percentage % 90% 90% 90% 90% 90% 90% 90% 90% 90% 90% 90% 90%
Total Cost Recovery Subject to Sharing $ 315,876 522,872 (2,728,295) (1,202,914) (967,805) (967,967) (1,447,025) 1,165,453 (197,622) (1,072,522) (204,530) 1,606,715 (5,177,764)
Energy Imbalance Market Incremental O&M Costs RI $ 37,917 33,993 24,835 24,322 26,012 28,407 32,205 26,428 25,328 32,087 29,628 39,629 360,791
Sharing Percentage % 90% 90% 90% 90% 90% 90% 90% 90% 90% 90% 90% 90% 90%
EIM O&M Costs Subject to Sharing 34,125 30,594 22,352 21,890 23,411 25,566 28,985 23,785 22,795 28,878 26,665 35,666 324,712
Total Power Cost Deferral with Adjustments(Balance Sheet $ 350,001 553,466 (2,705,943) (1,181,024) (944,394) (942,401) (1,418,040) 1,189,238 (174,827) (1,043,644) (177,865) 1,642,381 (4,853,052)
AVU-E-25-072025 Brandon Workpapers
Act-Auth-Proposed Page 2 of 6

Avista Corporation PCA -1
July 2024 through June 2025
IPUC Deferral Analysis
AVU-E-21-01 AVU-E-23-01 Jul-24 thru
J Deferral for 2024-25 Deferral Period ulul24 Aug-24 5ep-24 Oct-24 Nov-24 Dec-24 Jan an25 Feb-25 Mar-25 Apr-25 May-25 lun-25 Jun-25
Monthly Interest Rate % 0.41667% 0.41667% 0.41667% 0.41667% 0.41667% 0.41667% 0.41667% 0.41667% 0.41667% 0.41667% 0.41667% 0.41667% 0.41667% 0.41667% 0.41667%
PCA Ending Balances
Account 182385 June 2024 Ending Balance $ -
Account 182386 June 2024 Ending Balance $ 4,677,046
Account 182387 June 2024 Ending Balance $ (8,721,250)
2023-2024 Beginning Balance $ (4,044,204) (7,696,121) (8,516,361) (12,484,145) (14,230,448) (14,641,608) (14,912,036) (15,625,605) (13,743,722) (13,304,135) (13,777,453) (13,469,976) (11,302,437) (10,670,687) (10,069,643)
Current year Deferral-Account 182385 $ 350,001 553,466 (2,705,943) (1,181,024) (944,394) (942,401) (1,418,040) 1,189,238 (174,827) (1,043,644) (177,865) 1,642,381
RPS Compliance Adjustment $ (2,755,522)
Amortization-Account 182386 $ (1,229,545) (1,341,639) (1,226,356) (513,261)
Amortization-Account 182387 $ 592,529 732,982 766,605 757,753 671,679 625,760 542,748 581,283
Amortization-Projected $ 678,944 645,506 551,926
Ending Balance w/out Current Month Interest $ (7,679,270) (8,494,294) (12,448,660) (14,178,430) (14,582,313) (14,851,027) (15,563,471) (13,678,614) (13,246,870) (13,722,019) (13,412,570) (11,246,312) (10,623,593) (10,025,181) (9,517,717)
Interest $ (16,851) (32,067) (35,485) (52,018) (59,294) (61,007) (62,135) (65,108) (57,265) (55,432) (57,407) (56,125) (47,094) (44,462) (41,957)
2024-25 Final Ending Deferral Balance $ (7,696,121) (8,516,361) (12,484,145) (14,230,448) (14,641,608) (14,912,036) (15,625,605) (13,743,722) (13,304,135) (13,777,453) (13,469,976) (11,302,437) (10,670,687) (10,069,643) (9,559,674)
"'Per Avista ID General Rate Case,Case No.AVU-E-21-01,Order No.35156,section 6.Other Settlement Components,subpart E.Energy Imbalance Market("EIM")
AVU-E-25-072025 Brandon Workpapers
Act-Auth-Proposed Page 3 of 6

Source:EREV June Mid-month 06.12.25,Bill Determ Tab
Calendar Load(kWh)by Rate Schedule
Oct 25 Nov 25 Dec 25 Jan 26 Feb 26 Mar 26 Apr 26 May 26 Jun 26 Jul 26 Aug 26 Sep 26 Total
ID001 85,502,996 126,216,131 160,433,693 154,460,258 136,213,813 117,196,025 106,142,287 88,885,486 86,560,590 105,074,021 99,773,782 79,146,804 1,345,605,886
ID011 68,478,246 78,302,860 79,764,250 81,163,355 76,827,857 71,288,489 67,582,262 65,230,843 72,053,761 80,992,348 75,296,946 66,857,498 883,838,715
ID012 2,595,547 3,837,922 4,762,305 4,816,081 4,459,332 3,860,645 3,099,952 2,558,767 2,411,633 2,731,430 2,616,608 2,330,243 40,080,465
ID021 9,991,801 11,240,269 11,268,142 11,554,075 10,965,318 10,191,376 10,122,933 9,527,846 10,342,987 11,206,891 10,283,086 9,258,943 125,953,667
ID022 568,313 618,393 794,718 807,633 781,793 632,721 548,475 518,061 505,743 586,918 609,696 539,668 7,512,132
ID025 29,813,347 27,886,994 28,982,511 29,874,081 27,827,592 29,654,196 28,470,973 29,364,287 28,621,748 30,011,251 30,039,756 28,888,612 349,435,348
ID025P 31,076,036 25,567,465 31,812,481 30,185,203 26,192,902 33,566,746 27,382,230 33,680,891 29,301,442 35,329,467 34,406,514 30,127,989 368,629,366
ID031 4,826,290 2,517,763 3,125,062 3,291,282 3,467,407 3,269,511 3,104,613 4,585,085 6,699,409 7,710,159 9,355,561 6,211,054 58,163,196
ID032 212,087 202,440 252,301 275,708 233,493 209,390 196,991 283,225 465,015 876,340 879,341 427,832 4,514,163
ID04X 812,968 813,721 816,225 831,369 798,184 818,183 818,585 804,063 814,241 815,012 810,584 819,098 9,772,233
Total 233,877,631 277,203,958 322,011,688 317,259,045 287,767,691 270,687,282 247,469,301 235,438,554 237,776,569 275,333,837 264,071,874 224,607,741 3,193,505,171
3,193,505
Calendar Loads
Jul-25 Aug-25 Sep-25
ID001 105,440,387 97,963,024 78,536,322
ID011 81,737,549 75,322,280 67,482,257
ID012 2,670,639 2,498,473 2,256,000
ID021 11,323,793 10,291,791 9,343,852
ID022 586,654 600,129 547,201
ID025 29,491,893 30,229,149 28,300,444
ID025P 35,300,304 34,387,554 30,115,661
ID031 7,693,088 9,403,933 6,517,976
ID032 882,083 881,906 432,289
ID04X 826,291 822,489 827,980
Total 275,952,681 262,400,728 224,359,982 762,713,391
Present Rate -$0.00246 -$0.00246 -$0.00246
-$678,844 -$645,506 -$551,926
Present RCF* 0.995661 0.995661 0.995661
-$675,898 -$642,705 -$549,531 -$1,868,134
$ (259,383.35) $ (240,989.04) $ (193,199.35)
*Case No.AVU-E-23-01:Per Final Stipulation&Settlement
Revenue Total Oct 25 Nov 25 Dec 25 Jan 26 Feb 26 Mar 26 Apr 26 May 26 Jun 26 Jul 26 Aug 26 Sep 26
ID001 $ 165,358,413 $ 10,924,292 $ 15,107,672 $ 18,749,767 $ 18,204,180 $ 16,336,532 $ 14,424,637 $ 13,127,238 $ 11,288,557 $ 11,039,334 $ 12,892,068 $ 12,452,687 aauuuauuuaa a
ID011 $ 85,169,825 $ 6,653,729 $ 7,497,833 $ 7,608,327 $ 7,719,055 $ 7,345,952 $ 6,859,573 $ 6,549,501 $ 6,346,109 $ 6,918,386 $ 7,689,012 $ 7,194,388 $6,787,960
ID012 $ 5,110,182 $ 361,980 $ 466,048 $ 541,762 $ 547,781 $ 518,509 $ 468,274 $ 406,389 $ 361,248 $ 348,062 $ 374,146 $ 364,327 $ 351,656
ID021 $ 18,068,682 $ 1,464,258 $ 1,536,869 $ 1,548,030 $ 1,565,504 $ 1,539,174 $ 1,509,579 $ 1,484,242 $ 1,425,838 $ 1,469,292 $ 1,536,390 $ 1,490,594 $1,498,912
ID022 $ 670,066 $ 51,507 $ 54,959 $ 67,317 $ 68,665 $ 66,720 $ 56,184 $ 50,136 $ 47,959 $ 47,069 $ 52,750 $ 54,355 $ 52,445
ID025 $ 22,327,080 $ 1,896,943 $ 1,800,997 $ 1,848,819 $ 1,888,513 $ 1,789,864 $ 1,877,945 $ 1,814,410 $ 1,854,730 $ 1,821,220 $ 1,898,221 $ 1,899,915 $1,935,503
ID025P $ 36,136,441 $ 3,043,069 $ 2,705,006 $ 3,091,886 $ 3,141,868 $ 2,806,909 $ 3,248,054 $ 2,826,685 $ 3,086,747 $ 2,865,212 $ 3,226,223 $ 3,174,694 $2,920,088
ID031 $ 6,896,813 $ 576,045 $ 308,677 $ 379,022 $ 396,245 $ 416,487 $ 395,059 $ 375,281 $ 546,103 $ 780,831 $ 887,712 $ 1,071,659 $ 763,692
ID032 $ 680,283 $ 38,450 $ 37,305 $ 42,903 $ 45,390 $ 40,709 $ 38,087 $ 36,670 $ 46,451 $ 66,348 $ 111,467 $ 111,701 $ 64,802
ID04X $ 4,529,697 $ 375,782 $ 376,126 $ 377,266 $ 384,267 $ 368,937 $ 378,197 $ 378,387 $ 371,660 $ 376,363 $ 376,722 $ 374,677 $ 391,313
$ 344,947,482
AVU-E-25-07 2025 Brandon Workpapers
KWh Forecast and Rev Page 4 of 6

AVISTA UTILITIES
Settlement Revenue Conversion Factor
Idaho - Electric System
TWELVE MONTHS ENDED JUNE 30, 2024
Line
No. Description Factor
1 Revenues 1.000000
Expenses:
2 Uncollectibles 0.002212
3 Commission Fees 0.002127
4 Idaho Income Tax
5 Total Expenses 0.004339
6 Net Operating Income Before FIT 0.995661
Case No.AVU-E-23-01: Per Final Stipulation &Settlement
AVU-E-25-07 2025 Brandon Workpapers
Conversion Factor Page 5 of 6

Bill Determinants
2024 Idaho Annual PCA Filing
Present Proposed
Basic Charge $ 20.00 $ 20.00
Block 1 $ 0.08569 $ 0.08514
Block 2 $ 0.09703 $ 0.09648
Present Proposed
Bill Bill
Basic Charge $ 20.00 $ 20.00
Block 1 $ 51.41 $ 51.08 600
Block 2 $ 32.89 $ 32.71 339
Total Bill $ 104.30 $ 103.79 939
Total Bill Impact $ (0.51) -0.5%
AVU-E-25-07 2025 Brandon Workpapers
Bill Impact Page 6 of 6