------CHUG POWERING ALASKA'S futulle

------CHUG POWERING ALASKA'S futulle March 15, 2018 ELECTRONICALLY FILED WITH RCA Regulatory Commission of Alaska 701 W. 8 th Avenue, Suite 300 Anchorage, AK 99501 Subject: Tariff Advice N. 454-8; Annual Update to the G&T Loss Factor Commissioners: The tariff filing described below is hereby transmitted to you for filing in compliance with the Alaska Public Utilities Commission Act and Sections 3 AAC 48.200-3 AAC 48.420 of the Alaska Administrative Code. The purpose of this filing is to revise 's (Chugach) Operating Tariff to update its generation and transmission (G&T) loss factor based on calendar-year 2017 operating results. TARIFF SHEET NUMBER CANCELS SHEET NUMBER SCHEDULE OR ORIGINAL REVISED ORIGINAL REVISED RULE NUMBER 103.4 15 th Revision 103.4 14 th Revision Calculation of 103.5 15 th Revision 103.5 14 th Revision G&T Losses This filing is not for a new service, will not result in the termination of an existing service, conflict with any other schedule or rate contained in Chugach s operating tariff, or in any other way adversely impact customers or the public. The loss factor is used for the allocation of system costs between G&T and Distribution functions in Chugach s cost of service studies, fuel and purchased power rate adjustment processes, and determination of losses applied to transmission wheeling transactions. Approximately 68,000 Chugach retail members (81,200 retail metered locations) and Seward Electric System (Seward) are impacted by this filing. Chugach s total revenues associated with electric service are projected to be $206 million in calendar year 2018. If approved, the updated loss factor will decrease G&T cost responsibility to Seward by approximately $24,000 and Chugach retail will increase by approximately $24,000. In addition, there is no rate impact on third party transmission customers since Chugach is not changing its transmission wheeling rates. The update has no impact on Chugach s system revenue. The updated G&T loss factor is 2.207 percent, based on 2017 operating results, as measured at generation. This compares with loss factors of 2.810 percent and 2.414 percent based on 2016 and 2015 operating results, respectively. Since 2012 (excluding 2017 results), Chugach s loss factor has 5601 Electron Drive, P.O. Box 196300 Anchorage, Alaska 99519-6300 (907) 563-7494 Fax (907) 562-0027 (800) 478-7494 www.chugachelectric.com info@chugachelectric.com

Commissioners March 15, 2018 Page 2 of 3 averaged 2.579 percent, with a high of 2.875 percent in 2012 and a low of 2.312 percent in 2014. Previous G&T loss factors are summarized below: Table 1: Summary of Previous G&T Loss Factors (measured at generation) Test Year Percent Test Year Percent 2017 2.207 2014 2.312 2016 2.810 2013 2.486 2015 2.414 2012 2.875 Tariff Sheet Nos. 103.4 and 103.5 summarize the calculations and resulting G&T and Distribution loss percentages based on calendar year 2017 operating results. Supporting data are included on Attachments I and II. Compliance with U-99-106(12) The G&T loss factor was calculated in accordance with the methodology contained in the stipulation between Chugach, Homer Electric Association, Inc. (HEA) and Matanuska Electric Association, Inc. (MEA) and accepted by the Commission in Docket U-99-106(12). Pursuant to this order, preliminary 2017 test year loss factor calculations and supporting work papers were provided to HEA, MEA and the Attorney General s office for review and comment. Preliminary calculations and work papers were also provided to Golden Valley Electric Association, Inc., Anchorage Municipal Light & Power and Seward. A meeting was held on February 27, 2018, to review the calculations and discuss preliminary results with the other Railbelt utilities. Based on input from the other utilities and subsequent discussion, no changes to the calculation were required. The only modification to the 2017 test year loss calculation, was the addition of Hane Substation under the Distribution Substation Deliveries section on Attachment I. Hane Substation was added to Chugach s system in February 2017. Chugach is not aware of any outstanding issues associated with this year s update. Description of Tariff Changes Tariff Sheet 103.4: Updated to reflect actual 2017 energy flows entering and leaving the Chugach system. Tariff Sheet 103.5: Updated to reflect the proposed G&T loss factors as measured at both generation and delivery. This sheet also summarizes retail distribution loss activity during 2017.

Commissioners March 15, 2018 Page 3 of 3 Chugach requests that the updated loss factor become effective May 1, 2018. Questions regarding the filing should be directed to Jean Kornmuller, Manager Regulatory Affairs, at 907-762-4184. Sincerely, CHUGACH ELECTRIC ASSOCIATION, INC. Arthur W. Miller Vice President, Regulatory and External Affairs P.O. Box 196300 Anchorage, Alaska 99519-6300 Telephone: 907-762-4758 Arthur_Miller@chugachelectric.com Attachments cc: J. Foutz, City of Seward (electronic) D. Bishop, M. Grassi, D. Heckman, Golden Valley Electric Association, Inc. (electronic) A. Henderson, A. Thuya, Anchorage Municipal Light and Power (electronic) T. Clark, E. Jenkin, Matanuska Electric Association, Inc. (electronic) J. Patras, M. Peery, Homer Electric Association, Inc. (electronic)

RCA 8 15 th Revision Sheet No. 103.4 Canceling 14 th Revision Sheet No. 103.4 CALCULATION OF CHUGACH G&T LOSSES 2017 Test Year Description Q1-17 Q2-17 Q3-17 Q4-17 Total Energy Entering System Beluga Power Plant 43,590.0 31,934.7 14,450.2 62,985.3 152,960.2 IGT Power Plant 0.0 60.6 18.4 0.0 79.0 Fire Island Wind (IGT Bkr 532) 10,990.0 10,346.4 9,114.3 13,335.0 43,785.6 Southcentral Power Project 358,015.0 280,265.1 315,442.7 320,146.4 1,273,869.2 Quartz Creek Substation 72,981.1 66,232.9 84,907.7 100,976.1 325,097.7 AML&P Plant 2 22,993.1 44,350.6 32,436.9 31,377.0 131,157.6 Teeland Substation 88,371.0 121,497.2 92,861.1 104,139.7 406,869.1 University Substation Bkr 152 224.3 1,021.8 59.5 91.5 1,397.2 Douglas Substation 0.0 0.0 0.0 0.0 0.0 Cooper Lake Power Plant 7,786.1 13,913.5 1,899.1 1,130.8 24,729.5 AML&P to ITSS 145.0 3,790.1 1,518.4 1,343.1 6,796.6 Total Energy Entering System 605,095.7 573,412.7 552,708.2 635,525.0 2,366,741.6 Energy Leaving System Quartz Creek Substation 0.0 25.0 0.0 0.1 25.1 Daves Creek Substation 15,227.1 14,379.9 15,896.0 14,299.7 59,802.7 Douglas Substation 105,978.0 148,171.7 109,472.0 134,897.2 498,518.9 AML&P Plant 2 1,265.7 0.5 2,723.5 535.5 4,525.2 ITSS to AML&P 23,094.3 5,688.8 16,145.9 19,645.4 64,574.3 Teeland Substation 60,707.6 82,402.2 73,440.2 103,307.4 319,857.3 University Substation Bkr 152 54,176.2 44,156.2 52,967.9 27,656.6 178,956.9 Power Plant Station Service Totals 15,000.7 12,203.9 12,833.6 15,009.3 55,047.5 Distribution Substation Deliveries 319,549.4 260,464.9 262,425.1 312,385.9 1,154,825.2 Total Energy Leaving System 594,998.9 567,493.1 545,904.2 627,737.0 2,336,133.1 Gross Energy Losses 10,096.8 5,919.7 6,804.0 7,788.0 30,608.5 Less Transformer Losses 1,336.0 1,336.0 1,336.0 1,336.0 5,344.0 Net G&T Losses 8,760.8 4,583.7 5,468.0 6,452.0 25,264.5 Tariff Advice No.: 454-8 Effective: May 1, 2018 Issued by: P.O. Box 196300, Anchorage, Alaska 99519-6300 By: Lee D. Thibert Title: Chief Executive Officer

RCA 8 15 th Revision Sheet No. 103.5 Canceling 14 th Revision Sheet No. 103.5 CALCULATION OF CHUGACH G&T LOSSES 2017 Test Year 1 Description Q1-17 Q2-17 Q3-17 Q4-17 Total Chugach Retail Distribution Losses Retail Receipts at Transmission Substation 319,549.4 260,464.9 262,425.1 312,385.9 1,154,825.2 Less: Chugach House Power 1,343.3 944.4 841.9 1,159.9 4,289.5 Net Receipts 318,206.1 259,520.5 261,583.1 311,226.0 1,150,535.7 Retail Sales at Delivery 306,953.5 249,234.5 251,003.5 298,339.9 1,105,531.4 Losses 11,252.6 10,286.0 10,579.7 12,886.1 45,004.3 Add: 1/2 House Power 671.6 472.2 421.0 579.9 2,144.8 Adj. Retail Dist. Losses 11,924.3 10,758.2 11,000.6 13,466.0 47,149.1 At Delivery 3.885% 4.316% 4.383% 4.514% 4.265% At Transmission Substation 3.747% 4.145% 4.205% 4.327% 4.098% Adjustment of G&T Losses for House Power G&T Deliveries 334,776.5 274,844.5 278,321.1 326,685.5 1,214,627.6 Net G&T Losses 8,760.8 4,583.7 5,468.0 6,452.0 25,264.5 Add: 1/2 House Power 671.6 472.2 421.0 579.9 2,144.8 Adjusted G&T Losses 9,432.4 5,055.9 5,889.0 7,031.9 27,409.2 At Delivery 2.818% 1.840% 2.116% 2.153% 2.257% At Generation 2.740% 1.806% 2.072% 2.107% 2.207% R R 1 G&T loss factor effective for the allocation of actual costs beginning January 1, 2018. Tariff Advice No.: 454-8 Effective: May 1, 2018 Issued by: P.O. Box 196300, Anchorage, Alaska 99519-6300 By: Lee D. Thibert Title: Chief Executive Officer

PRELIMINARY Values used in calculation not rounded; data formatted to show the nearest tenth of a MWh. Measurement Point Source 1 Jan-17 Feb-17 Mar-17 Apr-17 May-17 Jun-17 Jul-17 Aug-17 Sep-17 Oct-17 Nov-17 Dec-17 Total 2017 Energy Entering System Beluga Power Plant Beluga 13.8 BKR 126 S 9.7 155.6 0.0 242.6 195.3 118.9 137.6 13.5 0.0 225.8 454.4 0.0 1,553.4 Beluga 13.8 BKR 226 S 87.2 450.8 158.6 264.0 337.1 438.1 0.0 71.4 0.0 55.2 351.2 0.0 2,213.6 Beluga 13.8 BKR 326 S 0.0 392.3 5,443.2 4,203.3 1,315.4 45.6 2,235.8 504.8 1,564.4 0.0 0.0 22.2 15,727.0 Beluga 13.8 BKR 526 S 13,643.0 6,206.8 14,162.0 6,294.1 7,800.0 8,369.7 1,486.6 2,223.4 4,386.3 4,930.2 16,256.6 14,638.1 100,396.7 Beluga 13.8 BKR 626 S 0.0 0.0 0.0 0.0 0.0 589.8 556.5 0.0 0.0 2,998.3 0.0 0.0 4,144.6 Beluga 13.8 BKR 726 S 0.0 2,880.8 0.0 1,020.8 0.0 700.0 699.2 0.0 570.7 15,693.8 5,813.2 1,546.5 28,925.0 Beluga 13.8 BKR 826 S 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Total Beluga Power Plant 13,739.9 10,086.3 19,763.8 12,024.8 9,647.8 10,262.1 5,115.7 2,813.1 6,521.4 23,903.3 22,875.3 16,206.7 152,960.2 IGT Power Plant IGT 13.8 BKR 426 S 0.0 0.0 0.0 18.4 21.5 0.0 0.0 0.0 0.0 0.0 0.0 0.0 39.9 IGT 13.8 BKR 726 S 0.0 0.0 0.0 0.00 20.70 0.0 0.0 0.00 18.40 0.0 0.0 0.0 39.1 IGT 13.8 BKR 1326 S 0.0 0.0 0.0 0.00 0.00 0.0 0.0 0.00 0.00 0.0 0.0 0.0 0.0 Total IGT Power Plant 0.0 0.0 0.0 18.4 42.2 0.0 0.0 0.0 18.4 0.0 0.0 0.0 79.0 Fire Island Wind (IGT Bkr 532) M 3,748.1 2,494.8 4,747.1 3,324.7 4,579.5 2,442.2 1,804.1 3,146.6 4,163.6 3,743.6 4,565.7 5,025.8 43,785.6 SPP Unit No. 1 / 10 S 18,911.3 17,297.7 21,958.2 13,510.7 7,799.9 14,879.6 17,221.4 16,657.3 16,811.3 10,935.9 15,170.6 17,613.6 188,767.5 Unit No. 2 / 11 S 22,543.8 20,091.4 22,436.2 17,926.1 19,542.6 18,524.3 18,818.4 18,256.9 18,547.2 16,415.8 16,155.8 21,707.0 230,965.5 Unit No. 3 / 12 S 22,502.8 20,119.3 22,563.2 16,870.2 19,720.6 11,647.2 18,891.2 18,274.6 18,663.9 18,545.7 22,750.3 22,929.8 233,478.9 Unit No. 4 / 13 S 22,635.6 19,991.0 25,279.7 15,288.2 19,550.0 18,489.6 18,768.2 17,713.8 18,539.2 15,395.9 22,587.8 22,834.2 237,073.1 ML&P Share O 38,124.3 31,083.5 32,477.0 29,124.2 28,832.2 28,559.7 32,332.9 32,634.1 33,312.3 26,426.4 33,823.9 36,853.8 383,584.1 Gross Generation 124,717.8 108,582.9 124,714.3 92,719.4 95,445.3 92,100.4 106,032.1 103,536.7 105,873.9 87,719.7 110,488.4 121,938.4 1,273,869.2 Quartz Creek Substation Soldotna 115 SldQtzLn M 34,482.2 31,587.4 6,911.4 23,978.4 25,426.1 16,828.4 24,666.4 27,867.9 32,373.4 34,890.3 35,183.6 30,902.2 325,097.7 Total Quartz Creek Substation 34,482.2 31,587.4 6,911.4 23,978.4 25,426.1 16,828.4 24,666.4 27,867.9 32,373.4 34,890.3 35,183.6 30,902.2 325,097.7 1 Source of Data: M: Metered data. S: SCADA interval data. O: Non-interval data. 2017 Test Year G&T Loss Factor_Monthly 2017 Attachment I Page 1 of 6

PRELIMINARY Values used in calculation not rounded; data formatted to show the nearest tenth of a MWh. Measurement Point Source 1 Jan-17 Feb-17 Mar-17 Apr-17 May-17 Jun-17 Jul-17 Aug-17 Sep-17 Oct-17 Nov-17 Dec-17 Total 2017 AML&P Plant 2 Plant 2 230 Yard S 8,191.7 8,278.3 6,523.1 13,096.2 14,787.8 16,466.6 13,847.7 10,226.5 8,362.7 13,094.6 5,521.6 12,760.8 131,157.6 Total AML&P Plant 2 8,191.7 8,278.3 6,523.1 13,096.2 14,787.8 16,466.6 13,847.7 10,226.5 8,362.7 13,094.6 5,521.6 12,760.8 131,157.6 University Substation University Bkr 152 Import S 0.0 0.0 224.3 750.9 0.5 270.4 28.7 0.7 30.1 30.3 30.0 31.2 1,397.2 Total University Bkr 152 Import 0.0 0.0 224.3 750.9 0.5 270.4 28.7 0.7 30.1 30.3 30.0 31.2 1,397.2 Teeland Substation Teeland 115 kv T1 M 0.0 1,415.7 170.3 0.0 0.0 1.1 0.0 878.3 381.8 0.0 0.0 0.0 2,847.3 Teeland 115 1452 M 20,505.9 30,888.0 35,391.0 35,328.0 40,938.3 45,229.9 33,983.3 30,291.7 27,326.0 33,706.1 36,490.5 33,943.1 404,021.9 Total Teeland Substation 20,505.9 32,303.8 35,561.3 35,328.0 40,938.3 45,231.0 33,983.3 31,170.1 27,707.8 33,706.1 36,490.5 33,943.1 406,869.1 Douglas Substation Douglas GVEA M 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Total Douglas Substation 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 Cooper Lake Power Plant Chugach CLPP M 4,576.6 3,209.6 0.0 1,638.4 5,801.2 6,473.8 1,854.3 44.8 0.0 24.5 119.2 987.1 24,729.5 Total Cooper Lake Power Plant 4,576.6 3,209.6 0.0 1,638.4 5,801.2 6,473.8 1,854.3 44.8 0.0 24.5 119.2 987.1 24,729.5 AML&P to ITSS S 11.6 133.4 0.0 1,438.1 897.6 1,454.5 227.1 898.8 392.5 1,265.6 2.2 75.3 6,796.6 Total Energy Entering System 209,973.9 196,676.5 198,445.3 184,317.1 197,566.3 191,529.3 187,559.4 179,705.2 185,443.6 198,377.9 215,276.5 221,870.6 2,366,741.6 1 Source of Data: M: Metered data. S: SCADA interval data. O: Non-interval data. 2017 Test Year G&T Loss Factor_Monthly 2017 Attachment I Page 2 of 6

PRELIMINARY Values used in calculation not rounded; data formatted to show the nearest tenth of a MWh. Measurement Point Source 1 Jan-17 Feb-17 Mar-17 Apr-17 May-17 Jun-17 Jul-17 Aug-17 Sep-17 Oct-17 Nov-17 Dec-17 Total 2017 Energy Leaving System Quartz Creek Substation Soldotna 115 SldQtzLn M 0.0 0.0 0.0 0.0 0.0 24.9 0.0 0.0 0.0 0.0 0.1 0.0 25.1 Total Quartz Creek Substation 0.0 0.0 0.0 0.0 0.0 24.9 0.0 0.0 0.0 0.0 0.1 0.0 25.1 Daves Creek Substation Daves Ck 115 BKR 952 M 5,199.4 4,623.0 5,404.7 4,574.4 4,948.5 4,856.9 5,559.8 5,626.8 4,709.4 4,590.3 4,783.5 4,925.8 59,802.7 Total Daves Creek Substation 5,199.4 4,623.0 5,404.7 4,574.4 4,948.5 4,856.9 5,559.8 5,626.8 4,709.4 4,590.3 4,783.5 4,925.8 59,802.7 Douglas Substation Douglas GVEA S 24,779.1 35,140.6 40,816.2 42,110.9 48,692.5 53,630.6 41,295.1 31,537.6 32,626.1 41,763.7 46,345.7 42,198.2 480,936.3 Douglas 115 MEA S 1,850.1 1,531.7 1,860.4 1,280.5 1,253.1 1,204.1 1,331.1 1,380.0 1,302.0 1,400.6 1,558.8 1,630.2 17,582.7 Total Douglas Substation 26,629.2 36,672.3 42,676.5 43,391.4 49,945.7 54,834.7 42,626.2 32,917.6 33,928.1 43,164.2 47,904.5 43,828.4 498,518.9 AML&P Plant 2 Plant 2 230 Yard S 19.4 864.1 382.1 0.0 0.0 0.5 0.0 1,815.2 908.3 51.7 346.6 137.2 4,525.2 Total AML&P Plant 2 19.4 864.1 382.1 0.0 0.0 0.5 0.0 1,815.2 908.3 51.7 346.6 137.2 4,525.2 ITSS to AML&P S 6,921.0 5,993.3 10,180.0 1,857.3 2,076.9 1,754.6 3,358.9 6,299.4 6,487.6 3,737.8 10,413.2 5,494.4 64,574.3 Teeland Substation Teeland 115 kv T1 M 18,839.5 16,423.0 20,293.5 23,624.9 25,490.6 27,204.4 25,672.5 19,957.9 20,737.4 28,655.2 35,904.0 31,393.6 294,196.5 Teeland 115 1452 M 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 2.4 5.2 0.8 0.1 8.6 Teeland 34.5 kv Bkr 332 M 1,920.7 1,569.8 1,661.0 1,507.1 2,408.6 2,166.5 2,251.7 2,394.0 2,424.3 2,814.5 2,729.7 1,804.2 25,652.2 Total Teeland Substation 20,760.2 17,992.8 21,954.5 25,132.0 27,899.2 29,370.9 27,924.2 22,351.9 23,164.1 31,475.0 38,634.5 33,197.9 319,857.3 University Substation University Bkr 152 Export S 27,143.9 24,528.2 2,504.1 13,737.6 18,728.2 11,690.4 14,631.8 15,519.2 22,816.8 11,041.2 0.0 16,615.4 178,956.9 Total University Bkr 152 Export 27,143.9 24,528.2 2,504.1 13,737.6 18,728.2 11,690.4 14,631.8 15,519.2 22,816.8 11,041.2 0.0 16,615.4 178,956.9 1 Source of Data: M: Metered data. S: SCADA interval data. O: Non-interval data. 2017 Test Year G&T Loss Factor_Monthly 2017 Attachment I Page 3 of 6

PRELIMINARY Values used in calculation not rounded; data formatted to show the nearest tenth of a MWh. Measurement Point Source 1 Jan-17 Feb-17 Mar-17 Apr-17 May-17 Jun-17 Jul-17 Aug-17 Sep-17 Oct-17 Nov-17 Dec-17 Total 2017 Power Plant Station Service - Includes Generation Step-up (GSU) transformers losses Beluga Station Service O 1,606.0 1,440.9 1,627.2 1,308.5 1,287.6 1,179.3 1,028.8 1,059.2 1,039.1 2,572.8 1,176.8 1,629.1 16,955.3 CLPP Station Service O 545.0 171.6 126.9 288.0 125.9 103.3 140.9 91.4 122.1 114.6 202.6 248.1 2,280.3 IGT Station Service O 109.9 139.9 113.4 71.0 37.6 41.0 51.6 92.7 68.8 116.3 160.6 137.4 1,140.1 SPP Station Service O 3,170.8 2,801.7 3,147.4 2,541.2 2,466.8 2,753.8 3,082.3 3,087.3 2,969.4 2,575.5 2,955.3 3,120.2 34,671.7 Total Station Service 5,431.7 4,554.1 5,014.9 4,208.6 3,917.8 4,077.5 4,303.6 4,330.5 4,199.4 5,379.2 4,495.3 5,134.8 55,047.5 Distribution Substation Deliveries Univ1132 S 12,796.3 10,789.4 11,530.4 3,503.2 4,267.8 7,108.6 8,884.6 8,985.7 9,465.4 10,479.3 11,528.1 12,026.5 111,365.1 Univ1232 S 7,929.6 6,820.9 7,466.6 6,225.9 6,019.4 5,459.4 4,687.4 6,701.2 6,148.7 6,932.5 7,690.7 7,988.8 80,071.1 Univ1332 S 4,667.0 3,921.4 4,179.1 4,113.5 3,408.4 3,312.4 3,611.1 3,690.3 3,078.6 3,542.6 3,961.5 4,180.0 45,665.9 Univ 1536 S 0.0 0.0 0.0 5,632.1 5,192.9 1,584.6 72.5 0.0 0.0 0.0 0.0 0.0 12,482.1 Beluga 15 6126 S 638.5 520.2 544.8 384.6 334.8 293.4 278.9 280.3 305.9 392.0 597.8 523.6 5,094.7 Beluga 15 1022 M 447.8 376.1 407.8 373.2 276.8 245.2 245.8 250.6 257.4 1,442.9 350.7 519.1 5,193.5 IGT 34.5 332 S 412.6 366.3 399.7 321.0 274.1 237.1 237.1 244.8 239.8 298.5 338.8 349.5 3,719.4 IGT 35 732 S 1,571.4 0.0 0.0 0.0 0.0 865.9 6,163.9 6,129.2 4,291.9 4,837.7 5,325.5 5,499.0 34,684.5 IGT 35 832 S 13,108.9 13,547.4 14,326.0 12,767.1 12,527.4 12,316.6 12,644.9 8,078.5 7,689.1 8,794.6 9,283.9 9,365.0 134,449.5 IGT 35 1232 S 9,315.0 7,866.7 8,271.9 596.6 3,949.3 3,933.5 4,755.7 5,408.2 7,234.5 8,068.1 8,897.7 9,449.9 77,747.1 IGT 35 1332 S 7,848.5 6,212.5 6,577.9 5,351.6 5,805.8 5,312.0 5,533.4 5,764.3 5,621.8 6,422.5 7,260.8 7,294.0 75,005.1 IGT 35 1532 S 6,404.3 5,561.2 6,039.7 5,177.3 3,547.1 4,001.0 4,175.6 4,532.0 4,050.0 4,399.4 4,565.0 5,084.3 57,536.8 Indian 212 M 248.9 214.4 241.5 189.7 186.4 174.8 187.2 196.0 199.5 215.2 231.0 230.8 2,515.4 Girdwood 422 S 1,370.3 1,117.1 1,291.3 957.5 804.5 708.2 885.6 753.8 767.4 905.4 1,087.1 1,207.5 11,855.7 Girdwood 322 S 1,092.9 941.9 1,063.2 747.7 647.8 676.5 573.7 757.4 696.6 733.2 1,744.0 1,375.0 11,049.9 Portage 422 S 797.9 697.5 804.1 659.3 691.0 745.7 996.7 846.7 693.7 679.5 740.8 822.5 9,175.5 Postmark S 4,800.7 4,248.7 4,707.8 5,529.9 4,927.8 4,211.6 4,540.7 4,581.6 4,173.3 4,391.3 4,489.5 4,663.3 55,266.2 Hope S 209.3 180.9 220.5 157.1 155.9 145.2 154.7 153.4 140.4 149.3 174.6 174.1 2,015.3 Summit M 13.4 9.3 10.6 11.3 33.3 33.8 1.0 0.0 0.0 0.0 0.0 0.0 112.8 Daves Creek M 808.0 694.0 799.6 657.6 751.2 779.7 807.2 788.6 720.2 671.0 703.6 690.4 8,871.3 Retherford (Net of 138kV breakers) S 40,538.6 32,840.5 34,641.2 34,402.0 31,844.0 28,881.1 25,525.8 28,884.0 28,642.5 31,525.6 34,019.0 35,965.9 387,710.3 Hane S 0.0 1,644.8 2,395.9 2,078.5 2,035.3 1,888.4 2,050.3 1,973.9 1,973.9 2,229.4 2,380.0 2,451.0 23,101.4 FIW Station Service S 16.0 8.3 14.5 12.0 13.5 7.1 1.7 7.8 10.1 14.5 15.0 16.3 136.8 Total Distribution Substation 115,035.8 98,579.5 105,934.1 89,848.6 87,694.3 82,922.0 87,015.7 89,008.4 86,401.0 97,124.5 105,384.9 109,876.4 1,154,825.2 Total Energy Leaving System 207,140.7 193,807.3 194,050.9 182,750.1 195,210.7 189,532.3 185,420.2 177,869.2 182,614.8 196,563.9 211,962.7 219,210.4 2,336,133.1 Gross Energy Losses 2,833.3 2,869.1 4,394.4 1,567.1 2,355.6 1,997.0 2,139.1 1,836.1 2,828.9 1,814.0 3,313.9 2,660.1 30,608.5 1 Source of Data: M: Metered data. S: SCADA interval data. O: Non-interval data. 2017 Test Year G&T Loss Factor_Monthly 2017 Attachment I Page 4 of 6

PRELIMINARY Values used in calculation not rounded; data formatted to show the nearest tenth of a MWh. Measurement Point Source 1 Jan-17 Feb-17 Mar-17 Apr-17 May-17 Jun-17 Jul-17 Aug-17 Sep-17 Oct-17 Nov-17 Dec-17 Total 2017 Less Transformer Losses University (w/ Station Load) O 168.5 168.5 168.5 168.5 168.5 168.5 168.5 168.5 168.5 168.5 168.5 168.5 2,022.0 Beluga O 32.6 32.6 32.6 32.6 32.6 32.6 32.6 32.6 32.6 32.6 32.6 32.6 390.8 Indian O 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 71.5 Girdwood O 29.6 29.6 29.6 29.6 29.6 29.6 29.6 29.6 29.6 29.6 29.6 29.6 355.0 Portage O 23.7 23.7 23.7 23.7 23.7 23.7 23.7 23.7 23.7 23.7 23.7 23.7 284.9 Hope O 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 27.8 Summit Lake O 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 24.1 Daves Creek O 16.8 16.8 16.8 16.8 16.8 16.8 16.8 16.8 16.8 16.8 16.8 16.8 201.7 International O 163.9 163.9 163.9 163.9 163.9 163.9 163.9 163.9 163.9 163.9 163.9 163.9 1,966.3 Total Transformer Losses 445.3 445.3 445.3 445.3 445.3 445.3 445.3 445.3 445.3 445.3 445.3 445.3 5,344.0 Net G&T Losses 2,387.9 2,423.8 3,949.0 1,121.7 1,910.3 1,551.6 1,693.8 1,390.7 2,383.5 1,368.7 2,868.5 2,214.8 25,264.5 1 Source of Data: M: Metered data. S: SCADA interval data. O: Non-interval data. 2017 Test Year G&T Loss Factor_Monthly 2017 Attachment I Page 5 of 6

PRELIMINARY Values used in calculation not rounded; data formatted to show the nearest tenth of a MWh. Measurement Point Source 1 Jan-17 Feb-17 Mar-17 Apr-17 May-17 Jun-17 Jul-17 Aug-17 Sep-17 Oct-17 Nov-17 Dec-17 Total 2017 Chugach Retail Distribution Losses Retail Receipts @ Trans SS 115,035.8 98,579.5 105,934.1 89,848.6 87,694.3 82,922.0 87,015.7 89,008.4 86,401.0 97,124.5 105,384.9 109,876.4 1,154,825.2 Less: Chugach House Pwr. O 446.8 419.9 476.5 342.7 296.2 305.5 272.7 276.0 293.3 343.5 410.6 405.7 4,289.5 Net Receipts 114,589.0 98,159.6 105,457.5 89,505.9 87,398.0 82,616.5 86,743.0 88,732.5 86,107.7 96,781.0 104,974.3 109,470.7 1,150,535.7 Retail Sales @ Delivery O 110,196.3 94,827.8 101,929.4 86,310.5 82,952.0 79,972.0 82,299.9 85,929.9 82,773.8 92,701.2 100,440.0 105,198.7 1,105,531.4 Losses 4,392.7 3,331.7 3,528.2 3,195.4 4,446.0 2,644.6 4,443.1 2,802.6 3,334.0 4,079.9 4,534.3 4,272.0 45,004.3 Add: 1/2 House Power 223.4 210.0 238.3 171.4 148.1 152.8 136.4 138.0 146.6 171.7 205.3 202.9 2,144.8 Adj. Retail Dist. Losses 4,616.1 3,541.7 3,766.5 3,366.7 4,594.1 2,797.3 4,579.4 2,940.6 3,480.6 4,251.6 4,739.6 4,474.8 47,149.1 At Delivery 4.189% 3.735% 3.695% 3.901% 5.538% 3.498% 5.564% 3.422% 4.205% 4.586% 4.719% 4.254% 4.265% At Transmission Substation 4.028% 3.608% 3.572% 3.761% 5.257% 3.386% 5.279% 3.314% 4.042% 4.393% 4.515% 4.088% 4.098% Adjustment of G&T Losses for House Power G&T Deliveries SES 5,199.4 4,623.0 5,404.7 4,574.1 4,948.5 4,856.9 5,559.8 5,626.8 4,709.4 4,590.3 4,783.5 4,925.8 59,802.3 RETAIL 115,035.8 98,579.5 105,934.1 89,848.6 87,694.3 82,922.0 87,015.7 89,008.4 86,401.0 97,124.5 105,384.9 109,876.4 1,154,825.2 Total Deliveries 120,235.2 103,202.5 111,338.8 94,422.7 92,642.8 87,778.9 92,575.5 94,635.2 91,110.4 101,714.8 110,168.5 114,802.3 1,214,627.6 Net G&T Losses 2,387.9 2,423.8 3,949.0 1,121.7 1,910.3 1,551.6 1,693.8 1,390.7 2,383.5 1,368.7 2,868.5 2,214.8 25,264.5 Add: 1/2 House Power 223.4 210.0 238.3 171.4 148.1 152.8 136.4 138.0 146.6 171.7 205.3 202.9 2,144.8 Adjusted G&T Losses 2,611.3 2,633.8 4,187.3 1,293.1 2,058.4 1,704.4 1,830.2 1,528.7 2,530.1 1,540.4 3,073.9 2,417.7 27,409.2 At Delivery 2.172% 2.552% 3.761% 1.369% 2.222% 1.942% 1.977% 1.615% 2.777% 1.514% 2.790% 2.106% 2.257% At Generation 2.126% 2.489% 3.625% 1.351% 2.174% 1.905% 1.939% 1.590% 2.702% 1.492% 2.714% 2.063% 2.207% 1 Source of Data: M: Metered data. S: SCADA interval data. O: Non-interval data. 2017 Test Year G&T Loss Factor_Monthly 2017 Attachment I Page 6 of 6

2017 Transformer Loss Calculations - Chugach Retail System Transformer Size (MVA) No Load Loss (MW) Full Load Loss (MW) Annual (MWh) Load Factor Transformer Losses at Load Factor (MW) Annual Losses (MWh) Beluga 1022 11.20 0.02200 0.10000 5,193.47 5% 0.022 195.16 Beluga 6126 10.00 0.02200 0.10000 5,094.74 6% 0.022 195.67 Daves Creek 10.00 0.02200 0.10000 8,871.33 10% 0.023 201.66 Girdwood 10.00 0.03100 0.14000 22,905.55 26% 0.041 354.95 Hope 1.25 0.00275 0.01250 2,015.32 18% 0.003 27.78 Indian 2.50 0.00770 0.03500 2,515.38 11% 0.008 71.47 Portage 10.00 0.03100 0.14000 9,175.47 10% 0.033 284.94 Summit 1.25 0.00275 0.01250 112.80 1% 0.003 24.10 UVSS 45.00 0.06500 0.53500 249,584.22 32% 0.118 1,036.51 UVSS Station Service Load 0.23 -- -- -- 50% 0.113 985.50 International T1 1 75.00 0.10204 0.13187 181,837.77 28% 0.112 981.85 International T2 1 75.00 0.10204 0.13187 184,476.80 28% 0.112 984.45 Total 5,344.04 1 MWh readings obtained from high side of the transformer. Excluded are MWh generated by IGT. 2017 Test Year G&T Loss Factor Xfmr_Losses 3/15/2018 Attachment II Page 1 of 1