20250630Supplemental Application.pdf

qN 010AW POWER.
MEGAN GOICOECHEA ALLEN
Corporate Counsel RECEIVED
mgoicoecheaallen(aD_idahopower.com
June 30, 2025
IDAHO PUBLIC
June 30, 2025 UTILITIES COMMISSION
Commission Secretary
Idaho Public Utilities Commission
11331 W. Chinden Boulevard
Building 8, Suite 201-A
Boise, Idaho 83714
Re: Case No. IPC-E-25-12
In the Matter of the Application of Idaho Power Company for a Determination
of 2024 Demand-Side Management Expenses as Prudently Incurred
Dear Commission Secretary:
Attached for electronic filing is Idaho Power Company's Supplemental Application and
the Direct Testimony of Quentin Nesbitt in support of the Supplemental Application in the
above-entitled matter.
A Word version of the testimony will be sent in an email for the convenience of the
Reporter.
If you have any questions about the attached documents, please do not hesitate to
contact me.
Sincerely,
Megan Goicoechea Allen
MGA:cd
Enclosures
P.O.Box 70(83707)
1221 W.Idaho St.
Boise,ID 83702

MEGAN GOICOECHEA ALLEN (ISB No. 7623)
LISA C. LANCE (ISB No. 6241)
Idaho Power Company
1221 West Idaho Street (83702)
P.O. Box 70
Boise, Idaho 83707
Telephone: [phone]
Facsimile: [phone]
mgoicoecheaallen(a-),idahopower.com
Ilance(c)_idahopower.com
Attorney for Idaho Power Company
BEFORE THE IDAHO PUBLIC UTILITIES COMMISSION
IN THE MATTER OF THE APPLICATION )
OF IDAHO POWER COMPANY FOR A ) CASE NO. IPC-E-25-12
DETERMINATION OF 2024 DEMAND-SIDE )
MANAGEMENT EXPENSES AS ) SUPPLEMENTAL APPLICATION
PRUDENTLY INCURRED. )
Idaho Power Company ("Idaho Power" or "Company") hereby respectfully submits
to the Idaho Public Utilities Commission ("Commission") this Supplement to the
Company's Application pursuant to Procedural Rule 52 seeking an order (1) designating
Idaho Power's 2024 Demand-Side Management ("DSM") expenses of $34,873,291, as
prudently incurred and (2) finding the Company complied with the directive outlined in
Order No. 363311 by conducting a follow-up to the impact evaluation of the Residential
New Construction ("RNC") Program using billing data.
In the Matter of Idaho Power Company's Application for a Determination of 2023 Demand-Side
Management Expenses as Prudently Incurred, Case No. IPC-E-24-11, Order No. 36331 (Sep. 26, 2024).
SUPPLEMENTAL APPLICATION - 1

In support of this Application, Idaho Power offers the Supplemental Direct
Testimony of Quentin Nesbitt ("Nesbitt Supplemental Testimony") filed
contemporaneously herewith and represents as follows:
I. BACKGROUND
1. Idaho Power considers energy efficiency and demand response to be an
important and necessary part of a balanced approach to meeting system energy needs,
and it endeavors to provide customers with program and knowledge through its DSM
program to help them use electricity wisely.
2. Energy efficiency programs are available to all customer segments in Idaho
Power's service area and focus on reducing energy use by identifying homes, buildings,
equipment, or components for which an energy-efficient design, replacement, or repair
can achieve energy savings. One of the Company's residential energy efficiency
programs is the RNC Program, which offers builders a cash incentive to build all energy
efficient, single-family, all-electric homes that use heat pump technology in Idaho Power's
Idaho service area. The homes must meet strict requirements that make them 10, 15, or
20 percent more energy efficient than homes built to standard state energy codes.
3. Energy savings for the RNC Program are calculated in accordance with the
Regional Technical Forum's ("RTF") New Homes Standard Protocol. The RTF and
Northwest Energy Efficiency Alliance have created specific simulated modeling
requirements and program guidelines to ensure the program provides reliable energy
savings for utilities across the Northwest.
4. To ensure the ongoing cost-effectiveness of its DSM programs through
validation of energy savings and demand reduction, and to guide the efficient
SUPPLEMENTAL APPLICATION - 2

management of its programs, the Company utilizes evaluations conducted by third-party
contractors including impact evaluations that are generally conducted every three years.
As reported in the Company's 2023 DSM prudency filing (Case No. IPC-E-24-11), in 2023
the RNC Program underwent a third-party impact evaluation, which was the program's
first evaluation since it transitioned from being a pilot program 2021. This impact
evaluation analyzed reported savings from the 2022 program year and found that the
tracking system and model output reports were well-organized, complete, and consistent,
resulting in a realization rate of 100 percent.
5. In evaluating the prudency of the Company's 2023 DSM expenses,
Commission Staff ("Staff") raised concerns with the methodology and simulated savings
basis of the 2023 RNC impact evaluation. More specifically, Staff questioned whether the
methodology comparing the model output savings of the REM/Rate model to itself
provided useful or meaningful results as an impact evaluation. Staff also stated it was
concerned with the use of simulated energy savings as a basis for the impact evaluation
and that the prior impact evaluation did not validate program savings estimates with a
high degree of rigor. Ultimately, Staff recommended the Commission direct the Company
to complete a follow-up evaluation of the RNC program using billing data to quantify the
energy saving impacts to the Company's system and further stated that the Company
should include recent data from the 2023 program year in the analysis, with data from
prior years being included if needed to ensure sufficient sample size. Staff also suggested
considering house occupancy and any relevant building code or program changes that
occurred in the analysis period.
6. As a result of the concerns raised by Staff regarding the 2023 RNC impact
SUPPLEMENTAL APPLICATION - 3

evaluation, in Order No. 36331 the Commission adopted Staff's recommendations and
ordered the Company to conduct a follow up evaluation of the RNC Program using billing
data.
7. Thereafter, the Company undertook efforts to fulfill the Commission's
directive. On November 26, 2024, the Company met with Staff to discuss the RNC follow-
up evaluation and the timeline for filing the results. In that discussion, the Company
discussed the planned scope of the follow-up evaluation and general timing of when the
evaluation would be completed. The Company also outlined the different possible
methodologies for a billing analysis and the unique challenges associated with
establishing a control group of comparable electric homes. The Company also informed
Staff that there was a sufficient sample of participants to produce statistically significant
results, but the nonparticipant sample size remained highly uncertain due to the difficulty
in identifying comparable, all-electric homes. After discussing the challenges associated
with conducting billing analyses on a new construction program and the available options,
the Company and Staff agreed that a study design featuring a nonparticipant control
group would be most appropriate though would still present limitations and would require
more time and resources to conduct.
8. In relation to the timeline for the RNC evaluation follow-up, Staff indicated
its desire for the for the evaluation to be completed somewhat promptly, though it
understood the results may not be available at the time the Company initiated its 2024
DSM prudency filing on March 14, 2025, and therefore proposed that the Company
submit the evaluation as a supplement to the 2024 prudence filing.
9. Accordingly, the Company noted in its Application filed in this matter that it
SUPPLEMENTAL APPLICATION -4

had pursued a follow-up evaluation of the RNC Program using billing data as ordered by
the Commission, though the results were not complete prior to the preparation of the
case, and as a result, the Company planned to file a supplement to the filing to submit
the results to the Commission. Therefore, having recently received the results from the
follow-up evaluation, the Company is providing this Supplemental Application along with
the Nesbitt Supplemental Testimony and exhibits thereto.
II. FOLLOW-UP EVALUATION RESULTS
10. After working with Staff to align on the scope and design of the follow-up
evaluation as directed by the Commission, the Company retained a third-party evaluator
("Evaluator") for the purpose of fulfilling the Commission's mandate. Thereafter, the
Evaluator completed a billing analysis evaluation in order to determine the consumption
difference between the RNC Program participant and nonparticipant all-electric homes
built in Idaho Power's Idaho service area during the same timeframe; the results of the
follow-up evaluation are presented in the RNC Follow-Up Evaluation included as Exhibit
No. 4 to the Nesbitt Supplemental Testimony.
11. The results of the analysis support the conclusion that the RNC Program is
delivering energy savings by motivating residential customers and builders to build above
code; this is demonstrated by the 17 percent reduction in winter electricity consumption
that the program participants achieved compared with a matched comparison group of
nonparticipants. The Evaluator concluded that the findings indicate that the RNC
Program's current guidelines and procedures are functioning as intended and result in
energy savings at participant homes.
12. In relation to the concerns raised by Staff in Case No. IPC-E-24-11 ,
SUPPLEMENTAL APPLICATION - 5

pertaining to the use of simulated energy savings as a basis for an impact evaluation, the
Evaluator explained that the RNC Program's simulation protocols produced modeled
consumption estimates that are, on average, within five percent of actual usage, a level
of alignment that supports the accuracy of the current guidelines and software used for
energy model simulation.
13. The Evaluator suggested that Idaho Power continue to coordinate with the
RTF on the modeling practices for the energy use of newly constructed homes; while the
Evaluator found that the current guidelines and software are acceptable, it expected that
RTF research and guidance will continue to evolve over time.
III. CONCLUSION
14. Based on the Evaluator's conclusions and recommendations, the Company
plans to continue to calculate savings for the RNC Program in accordance with the model
requirements and guidelines outlined in the New Homes Standard Protocol. In addition,
the Company will continue to keep up with the latest guidelines and protocols and to
coordinate with the RTF on new home modeling practices; it also intends to send the
RNC Follow-Up Evaluation to the RTF analyst team, which has indicated to the Company
that the results may help inform process improvements in the future.
15. The Company respectfully requests the Commission issue an order: (1)
designating Idaho Power's 2024 DSM expenses of $34,873,291 as prudently incurred
and (2) finding the Company complied with the directive outlined in Order No. 36331 to
conduct a follow-up impact evaluation of the RNC Program using billing data.
Respectfully submitted this 30t" day of June 2025.
SUPPLEMENTAL APPLICATION - 6

AwrL,Tl,yt�UA fik
MEGAN GOICOECHEA ALLEN
Attorney for Idaho Power Company
SUPPLEMENTAL APPLICATION - 7

CERTIFICATE OF SERVICE
I HEREBY CERTIFY that on the 30th day of June, 2025, 1 served a true and correct
copy of Idaho Power Company's Supplemental Application upon the following named
parties by the method indicated below, and addressed to the following:
Commission Staff Hand Delivered
Chris Burdin U.S. Mail
Deputy Attorney General Overnight Mail
Idaho Public Utilities Commission FAX
11331 W. Chinden Blvd., Bldg No. 8 FTP Site
Suite 201-A (83714) X Email Chris.Burdin(a)_puc.idaho.gov
PO Box 83720
Boise, ID 83720-0074
Christy Davenport
Legal Administrative Assistant
SUPPLEMENTAL APPLICATION - 8