20211201Avista to Staff Supplemental 1.pdf

AVISTA CORPORATION
RESPONSE TO REQUEST FOR INFORMATION
JURISDICTION: IDAHO DATE PREPARED: 12/1/2021
CASE NO: AVU-E-21-14 WITNESS: Clint Kalich
REQUESTER: Staff RESPONDER: John Lyons
TYPE: Production Request DEPARTMENT: Energy Resources
REQUEST NO.: Staff-001 TELEPHONE: [phone]
REQUEST:
Please answer the following questions regarding the load forecast in Case No. AVU-E-21-14.
a.Please explain why the Company used last year's load forecast in Case No. AVU-E-20-10 for
this year's annual update.
b.Please confirm that last year's load forecast was developed in the summer of 2020.
c.If a newer load forecast has become available since Case No. AVU-E-20-10 was submitted,
please provide the data. If not, please explain why there is not a newer load forecast available.
RESPONSE:
a.The load forecast submitted in Case No. AVU-E-21-14 was the latest data available as of
October 15th. A preliminary updated load forecast has been completed, but still needs to be
reviewed and finalized internally prior to submitting and utilizing for planning purposes due to
major assumption changes involved with the new load forecast, such as splitting the Idaho and
Washington load out from each other.
Update: The new load forecast from November 2021 has been reviewed and finalized.
b.Yes, the load forecast submitted in this filing was developed in the summer of 2020.
c.As explained in part a above, the new load forecast has been developed, but has not been
finalized and approved for use at this point in time.
Update: The new load forecast developed in November 2021 is as follows:
Year Load (aMW)
2023 1,117.0
2024 1,119.7
2025 1,122.3
2026 1,125.3
2027 1,128.8
2028 1,132.8
2029 1,135.4
2030 1,137.5
RECEIVED
2021 DEC -1 12:46 PM
IDAHO PUBLIC
UTILITIES COMMISSION
2031 1,139.5
2032 1,142.0
2033 1,143.3
2034 1,145.2
2035 1,147.1
2036 1,149.8
2037 1,151.4
2038 1,153.7
2039 1,156.2
2040 1,159.9
2041 1,162.6
2042 1,166.6
2043 1,171.2
2044 1,177.3
2045 1,183.1

The major changes to the new forecast include:
• showing the splits between the Idaho and Washington portions of the load forecast
before combining into the system load;
• updates made with historical data collected since the summer of 2020 forecast;
• updated data on the number of electric vehicles and use per vehicle based on studies
from Pacific Northwest National Laboratories; and
• compared to the 2021 IRP, the allocation of solar load over the months is more
precisely allocated using data from Avista's community solar installation.