20160722AVU to Staff 91.doc

AVISTA CORPORATION
RESPONSE TO REQUEST FOR INFORMATION

JURISDICTION: IDAHO DATE PREPARED: 07/20/2016
CASE NO.: AVU-E-16-03 WITNESS: Clint Kalich
REQUESTER: IPUC RESPONDER: James Gall
TYPE: Production Request DEPARTMENT: Energy Resources
REQUEST NO.: Staff - 091 TELEPHONE: [phone]

REQUEST:

The “ID Forward to Aurora Mid-C Price Comparison_2017” excel file in Kalich’s Confidential Workpapers uses the following formula to calculate the “average forwards price” in Column K:
Average forward Prices (Off-Peak Price * Heavy Load Hours + On-Peak Price * Light Load Hours) / Total Number of Hours

Please use the correct formula in the calculation:
Average forward Prices — (On-Peak Price * Heavy Load Hours + Off-Peak Price * Light
Load Hours) / Total Number of Hours

Please provide a correct version of the file and discuss the impacts of the mistake, if any, on the
rate case.

RESPONSE:

Please see Avista's response 091C, which contains TRADE SECRET, PROPRIETARY or CONFIDENTIAL information and exempt from public view and is separately filed under IDAPA 31.01.01, Rule 067 and 233, and Section 9-340D, Idaho Code, and pursuant to the Protective Agreement between Avista and IPUC Staff dated June 1, 2016.

Please see Staff_PR_091C Confidential Attachment A for a corrected version. The correction to the file relates to a calculated price of Flat Mid-C power from the forward market. The original formula multiplied the incorrect factor of on-peak hours and off-peak hours to derive the flat price. This price was created as an illustration to compare AURORA prices to the forwards, but was not ultimately used. Further, this incorrect price was not used in any of the calculation for the pro-forma power supply costs. The file is being provided in electronic form only.

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