Page 1 Page 2 Page 3 Page 4 Page 5 Page 6 Page 7 Page 8 Page 9 Page 10 Page 11 Page 12 Page 13 Page 14 Page 15 Page 16 Page 17 Page 18 Page 19 Page 20 Page 21 Page 22 Page 23 Page 24 Page 25 Page 26 Page 27 Page 28 Page 29 Page 30 Page 31 Page 32 Page 33 Page 34 Page 35 Page 36 Page 37 Page 38 Page 39 Page 40 Page 41 Page 42 Page 43 Page 44 Page 45 Page 46 Page 47 Page 48 Page 49 Page 50 Page 51 Page 52 Page 53 Page 54 Page 55 Page 56 Page 57 Page 58 Page 59 Page 60 Page 61 Page 62 Page 63 Page 64 Page 65 Page 66 Page 67 Page 68 Page 69 Page 70 Page 71 Page 72 Page 73 Page 74 Page 75 Page 76 Page 77 Page 78 Page 79 Page 80 Page 81 Page 82 Page 83 Page 84 Page 85 Page 86 Page 87 Page 88 Page 89 Page 90Seattle City Light 2015 Annual Report THE CITY OF SEATTLE—CITY LIGHT DEPARTMENT NOTES TO FINANCIAL STATEMENTS AS OF AND FOR THE YEARS ENDED DECEMBER 31, 2015 AND 2014 - 60 - accounts to defer the accounting impact of these accounting adjustments in accordance with GASB Statement No. 62, Codification of Accounting and Financial Reporting Guidance Contained in Pre- November 30, 1989 FASB and AICPA Pronouncements (see Notes 6 Other Assets and 15 Deferred Inflows of Resources). Market Risk—Market risk is, in general, the risk of fluctuation in the market price of the commodity being traded and is influenced primarily by supply and demand. Market risk includes the fluctuation in the market price of associated derivative commodity instruments. Market risk may also be influenced by the number of active, creditworthy market participants, and to the extent that nonperformance by market participants of their contractual obligations and commitments affects the supply of, or demand for, the commodity. Because the Department is active in the wholesale energy market, it is subject to market risk. Credit Risk—Credit risk relates to the potential losses that the Department would incur as a result of nonperformance by counterparties of their contractual obligations to deliver energy or make financial settlements. Changes in market prices may dramatically alter the size of credit risk with counterparties, even when conservative credit limits are established. The Department seeks to mitigate credit risk by: entering into bilateral contracts that specify credit terms and protections against default; applying credit limits and duration criteria to existing and prospective counterparties; and actively monitoring current credit exposures. The Department also seeks assurances of performance through collateral requirements in the form of letters of credit, parent company guarantees, or prepayment. The Department has concentrations of suppliers and customers in the electric industry including: electric utilities; electric generators and transmission providers; financial institutions; and energy marketing and trading companies. In addition, the Department has concentrations of credit risk related to geographic location as it operates in the western United States. These concentrations of counterparties and concentrations of geographic location may impact the Department’s overall exposure to credit risk, either positively or negatively, because the counterparties may be similarly affected by changes in conditions. Other Operational and Event Risk—There are other operational and event risks that can affect the supply of the commodity, and the Department’s operations. Due to the Department’s primary reliance on hydroelectric generation, the weather, including spring time snow melt, runoff, and rainfall, can significantly affect the Department’s operations. Other risks include regional planned and unplanned generation outages, transmission constraints or disruptions, environmental regulations that influence the availability of generation resources, and overall economic trends. 17. LONG-TERM PURCHASED POWER, EXCHANGES, AND TRANSMISSION Bonneville Power Administration—The Department purchases electric energy from the U.S. Department of Energy, Bonneville Power Administration (Bonneville) under the Block and Slice Power Sales Agreement, a 17-year contract, for the period October 1, 2011 through September 30, 2028. Block quantities, Slice percentage and Bonneville rates are expected to be recalculated periodically during the term of the contract. Rates will be developed and finalized every two years. Accordingly, certain estimates and assumptions were used in the calculations in the estimated future payments table below. The terms of the Slice product specify that the Department will receive a percentage of the actual output of the Federal Columbia River Power System (the System). The percentage is adjusted annually with a Slice Adjustment Ratio no greater than 1.0 times the 3.65663 initial slice percentage, no later than 15 days prior to the first day of each federal fiscal year, beginning with fiscal year 2012. The current Slice 60