20230922PAC to Staff 13.pdf

1407 W North Temple, Suite 330 Salt Lake City, Utah 84116
September 22, 2023 Jan Noriyuki Idaho Public Utilities Commission 472 W. Washington
Boise, ID 83702-5918 [e-mail] (C) RE: ID PAC-E-23-17
IPUC Set 2 (13) Please find enclosed Rocky Mountain Power’s Response to IPUC 2nd Set Data Request 13. If you have any questions, please feel free to call me at [phone].
Sincerely, ____/s/____ Mark Alder Manager, Regulation Enclosures

RECEIVED
Friday, September 22, 2023 3:29:09 PM
IDAHO PUBLIC
UTILITIES COMMISSION
PAC-E-23-17 / Rocky Mountain Power September 22, 2023 IPUC Data Request 13
IPUC Data Request 13 Section 4.5 of the Company's On-Site Generation Study describes an export avoided risk value of $1.24 per megawatt-hour (MWh) based on the same risk
values as the 2021 Integrated Resource Plan (IRP) energy efficiency stochastic
risk analysis. The 2021 IRP Volume 1 provides an energy efficiency risk reduction credit of $3 .59/MWh. PacifiCorp 2021 IRP Volume 1 at 213.
(a) Please explain the difference between the energy efficiency risk reduction
credit presented in the 2021 IRP and export avoided risk value contained in the on-site generation study in this case; (b) Please explain why it is appropriate to use the avoided risk values of energy efficiency programs to represent the avoided risk value of customer exports;
and
(c) Please describe how customer generation export risk values are like energy efficiency risk values, how they are different, and what the Company has done
to account for any differences.
Response to IPUC Data Request 13 (a) The risk reduction value of $3.59 per megawatt-hour ($/MWh) identified within PacifiCorp’s 2021 Integrated Resource Plan (IRP) was developed at the
beginning of the IRP modeling process and was used as a driver to incent the
model to select more energy efficiency (EE) for the risk reducing benefits it provides. The value used within the On-Site Generation Study was calculated based on the stochastic risk analysis performed on the final 2021 IRP
preferred portfolio, at the end of the 2021 IRP process. In addition, the risk
reduction value of EE from the 2021 IRP was converted to a percentage, and that percentage was applied to the energy values of specific EE programs. This same treatment was applied to customer exports in the On-Site Generation Study. Customer exports are higher during daylight hours when marginal energy costs are lower, while EE measures vary widely, but are
frequently either relative flat, or higher during more valuable periods, for
example cooling measures provide greater savings during high-temperature days in the summer. As a result, when the risk reduction is applied to customer exports as a percentage of energy value, it results in a lower number on a $/MWh basis than for EE. (b) Both customer generation and EE act as distributed resources reducing loads in close proximity to customers, so a similarity in their impact on the system is plausible. Both EE and customer exports are outside the control of the Company, so they do not vary in response to system conditions. Most
importantly, the Company has not calculated avoided risk values for other
PAC-E-23-17 / Rocky Mountain Power September 22, 2023 IPUC Data Request 13
resource types. While customer exports could potentially be considered more analogous to utility-scale solar resources, a large number of small distributed customer generators could have different impacts from a relatively small number of large utility-scale generators.

(c) Please refer to the Company’s responses to subparts (a) and (b) above.
Recordholder: Dan MacNeil
Sponsor: Dan MacNeil