20260116APPLICATION.pdf

INTERMOUNTAIN° RECEIVED
GAS COMPANY January 16, 2026
A Subsidiary of MDU Resources Group,Inc. I DAH O PUBLIC
In the Community to Serve® UTILITIES COMMISSION
January 16, 2026
Ms. Monica Barrios-Sanchez
Commission Secretary
Idaho Public Utilities Commission
P.O. Box 83720
Boise, ID 83720-0074
RE: Case No. INT-G-26-02
Dear Ms. Barrios-Sanchez:
Attached for consideration by this Commission is an electronic submission of Intermountain Gas
Company's Application for Authority to Revise Rate Schedule EE-RS—Residential Energy
Efficiency Rebate Program.
If you should have any questions regarding the attached,please don't hesitate to contact me at (509)
528-9223.
Sincerely,
Is/Michael Parvinen
Michael Parvinen
Director, Regulatory Affairs
Intermountain Gas Company
Enclosure
cc: Preston Carter

Preston N. Carter, ISB No. 8462
Megann E. Meier, ISB No. 11948
GIVENS PURSLEY LLP
601 West Bannock Street
P.O. Box 2720
Boise, Idaho 83701-2720
Office: [phone]
Fax: [phone]
Attorneys for Intermountain Gas Company
BEFORE THE IDAHO PUBLIC UTILITIES COMMISSION
IN THE MATTER OF THE Case No. INT-G-26-02
APPLICATION OF INTERMOUNTAIN
GAS COMPANY FOR AUTHORITY TO APPLICATION
REVISE RATE SCHEDULE EE-RS—
RESIDENTIAL ENERGY EFFICIENCY
REBATE PROGRAM
Intermountain Gas Company("Intermountain"or"Company"), a subsidiary of MDU
Resources Group,Inc. with general offices located at 555 South Cole Road,Boise,Idaho,pursuant
to the Rules of Procedure of the Idaho Public Utilities Commission("Commission"), requests
authority to revise Rate Schedule EE-RS—Residential Energy Efficiency Rebate Program as
outlined in this application, effective March 1,2026.
Please address communications regarding this Application to:
Preston N. Carter
Megann E. Meier
Givens Pursley LLP
601 W. Bannock St.
Boise, Idaho 83702
[e-mail]
[e-mail]
[e-mail]
and
APPLICATION- I

Michael Parvinen
Director—Regulatory Affairs
Intermountain Gas Company
Post Office Box 7608
Boise, ID 83707
[e-mail]
[e-mail]
In support of this Application,Intermountain alleges and states as follows.
I. INTRODUCTION
Intermountain is a gas utility, subject to the jurisdiction of the Commission, engaged in the
sale of and distribution of natural gas within the State of Idaho under authority of Commission
Certificate No. 219, issued December 2, 1955, as amended and supplemented by Order No. 6564,
dated October 3, 1962.
Intermountain provides natural gas service to the following Idaho communities and counties
and adjoining areas:
Ada County-Boise,Eagle,Garden City,Kuna,Meridian,and Star;
Bannock County-Arimo,Chubbuck,Inkom,Lava Hot Springs,McCammon,and Pocatello;
Bear Lake County-Georgetown,and Montpelier;
Bingham County-Aberdeen,Basalt,Blackfoot,Firth,Fort Hall,Moreland/Riverside, and Shelley;
Blaine County-Bellevue,Hailey,Ketchum,and Sun Valley;
Bonneville County-Ammon,Idaho Falls,Iona,and Ucon;
Canyon County-Caldwell,Greenleaf,Middleton,Nampa,Parma,and Wilder;
Caribou County-Bancroft,Grace,and Soda Springs;
Cassia County-Burley,Declo,Malta,and Raft River;
Elmore County-Glenns Ferry,Hammett,and Mountain Home;
Fremont County-Parker,and St. Anthony;
Gem County-Emmett;
Gooding County-Bliss,Gooding,and Wendell;
Jefferson County-Lewisville,Menan,Rigby,and Ririe;
Jerome County-Jerome;
Lincoln County- Shoshone;
Madison County-Rexburg,and Sugar City;
Minidoka County-Heybum,Paul,and Rupert;
Owyhee County-Bruneau, and Homedale;
Payette County-Fruitland,New Plymouth,and Payette;
Power County-American Falls;
Twin Falls County-Buhl,Filer,Hansen,Kimberly,Murtaugh,and Twin Falls;
Washington County-Weiser.
APPLICATION-2

Intermountain's properties in these locations consist of transmission pipelines, liquefied
natural gas storage facilities, compressor stations, distribution mains, services,meters and
regulators, and general plant and equipment.
II. BACKGROUND
In Order No. 36797,the Commission directed the Company to"include an EM&V with a
billing analysis covering Whole Home Tier I and Furnace measures"in its next prudency filing.
Order No. 36797 at 13. The Company then filed a petition for clarification or reconsideration
regarding this directive. In Order No. 36860,the Commission"declined to provide guidance as to
the appropriate timeframe from which the Company should draw billing data for the ordered
EM&V study or to limit the instances in which such a study is required."Order No. 36860 at 3.
However,the Commission did provide further clarification regarding the Company's offer to retire
the Whole Home Tier I measure without a separate filing by stating: "the Commission sees fit to
issue clarification of Order No. 36797 regarding the Company's offer to retire the Whole Home Tier
I measure. We find it more appropriate for the Company to submit a separate application to request
changes to its existing DSM programs so that interested parties may participate in the proceeding."
Id. As further explained below,this Application seeks to retire the Whole Home Tier I measure.
III. WHOLE HOME TIER I MEASURE
The Whole Home Tier I measure was not evaluated in the 2024 EM&V study due to lack of
participation in the rebate for the specific time period, leaving inadequate data for a meaningful
evaluation. In the Comments of the Commission Staff("Comments")in Case No. INT-G-24-05,
the Commission Staff acknowledged the lack of billing analysis data due to limited participation
and attempted to estimate the therm savings that could result from a billing analysis by using the
Whole Home Tier II realization rate. Comments at 17. This method of calculation produced a
APPLICATION-3

therm savings estimate of approximately 62.65 therms/home,however,the Commission Staff
acknowledged that"[s]avings for the Tier I rebate would likely be higher due to the higher air
sealing requirement,higher furnace efficiency requirement, and additional insulation requirement."
Id. Ultimately,the Commission Staff did not think that these additional requirements would be
enough to overcome the"120-therm difference between the claimed savings and savings adjusted
by the Tier II realization rate."Id.
In Order No. 36797,the Commission rejected"the Company's request to use the deemed
savings approach as the primary methodology for evaluating the cost-effectiveness of the
Company's EE program." Order No. 36797 at 12. The Commission further stated that it has
"directed utilities to use a billing analysis where appropriate, such as the instant case."Id.
Using the Commission Staff s therm savings estimate of 62.65 therms for the Whole Home
Tier I rebate in the Company's 2024 cost-effectiveness testing calculation provided in Case No.
INT-G-25-05,the Whole Home Tier I rebate measure is not cost-effective.
Given this result, as well as the limited Whole Home Tier I billing data available for analysis
(which may not produce statistically significant results),the Company predicts that an EM&V study
based on available billing data will return a per-home therm saving level that will not be cost-
effective. Under these circumstances,the Company believes there is substantial doubt regarding the
prudency of the expense of an EM&V study on the Whole Home Tier I measure.
The Company,therefore,requests authority to retire the Whole Home Tier I measure, and
that the Company not be required to conduct an EM&V with a billing analysis for this measure in
its next prudency filing, as would otherwise be required by Order No. 36797.
APPLICATION-4

IV. PROPOSED REVISIONS TO RATE SCHEDULE EE-RS
Based on the information provided above,the Company proposes to revise Rate Schedule
EE-RS as shown in Exhibit Nos. 1 and 2,which provide both legislative and clean copies of the
proposed changes.
The Company proposes an effective date of March 1, 2026 for these proposed revisions.
V. MODIFIED PROCEDURE
Intermountain requests that this matter be processed pursuant to Rules 201-204 under the
Commission's Rules of Modified Procedure. Intermountain stands ready to respond to any requests
for information in this matter.
VI. REQUEST FOR RELIEF
Intermountain respectfully petitions the Idaho Public Utilities Commission as follows:
a. That the Commission approve the proposed revisions to Rate Schedule EE-RS outlined
in this application, effective March 1,2026;
b. That the Company no longer be required to produce an EM&V with a billing analysis for
the Whole Home Tier I measure in its next prudency filing as required by Order No.
36797;
c. That this Application be heard and acted upon without hearing under modified
procedure; and
d. For such other relief as this Commission may determine proper.
Dated: January 16, 2026.
GIVENS PURSLEY LLP
By Al Preston N. Carter
Preston N. Carter
Givens Pursley LLP
Attorneys for Intermountain Gas Company
APPLICATION-5

CERTIFICATE OF SERVICE
I hereby certify that on January 16, 2026, I caused to be served a true and correct copy of
the foregoing document to the person(s) listed below by the method indicated:
Commission Staff Via Electronic Mail
Monica Barrios-Sanchez, Commission Secretary [e-mail]
Idaho Public Utilities Commission
11331 W. Chinden Blvd., Bldg. 8, Suite 201-A
Boise, ID 83714
/s/Chris Shoop
Chris Shoop—Regulatory Affairs Analyst
APPLICATION-6

EXHIBIT NO. 1
CASE NO. INT-G-26-02
INTERMOUNTAIN GAS COMPANY
Proposed Tariff—Legislative Format
(1 page)

I.P.U.C. Gas Tariff
Rate Schedules IDAHO PUBLIC UTILITIES COMMISSION
C�h Sixth Revised Sheet No. 16 (Page 2 of 2 Approved Effective
Name December 10.2025 januaryr2026
of Utility Intermountain Gas Company Per36866
Commissiea SecretayF
Rate Schedule EE-RS
RESIDENTIAL ENERGY EFFICIENCY REBATE PROGRAM
(Continued)
REBATES:
Rebate Rebate Type Minimum Efficiency Rating Rebate
Amount
Whole Home Tier 1 New Tier 1 Requirements: $9W
GenStFUGtieR a HERS Fated
• Air cooling at or belev.f 4 ACH of 50 Pa
• D Gts and air handier lgnated inside
e hsude of loos than n GFM25/100#2 GF
0
Combination Boiler for Space Heating 95%AFUE $800
Space and Water Heat
Furnace Space Heating 95%AFUE $275
Boiler Space Heating 95%AFUE $800
Tankless Water Water Heating .91 UEF $325
Heater Tier I
GENERAL PROVISIONS:
All installations of equipment must comply with all codes and permit requirements applicable in the state
of Idaho and must be properly inspected, if required, by appropriate agencies. Customers must submit
required documentation of purchase and installation to the Company under the Terms and Conditions of
the current rebate program. The Company reserves the right to verify installation prior to the payment of
any rebates.
Issued by: Intermountain Gas Company
By: Michael Parvinen Title: Director— Regulatory Affairs
Effective: March 1, 2026

EXHIBIT NO. 2
CASE NO. INT-G-26-02
INTERMOUNTAIN GAS COMPANY
Proposed Tariff—Clean Format
(1 pages)

I.P.U.C. Gas Tariff
Rate Schedules
Sixth Revised Sheet No. 16 (Page 2 of 2
Name
of Utility Intermountain Gas Company
Rate Schedule EE-RS
RESIDENTIAL ENERGY EFFICIENCY REBATE PROGRAM
(Continued)
REBATES:
Rebate Rebate Type Minimum Efficiency Rating Rebate
Amount
Combination Boiler for Space Heating 95%AFUE $800
Space and Water Heat
Furnace Space Heating 95%AFUE $275
Boiler Space Heating 95%AFUE $800
Tankless Water Water Heating .91 UEF $325
Heater Tier I
GENERAL PROVISIONS:
All installations of equipment must comply with all codes and permit requirements applicable in the state
of Idaho and must be properly inspected, if required, by appropriate agencies. Customers must submit
required documentation of purchase and installation to the Company under the Terms and Conditions of
the current rebate program. The Company reserves the right to verify installation prior to the payment of
any rebates.
Issued by: Intermountain Gas Company
By: Michael Parvinen Title: Director— Regulatory Affairs
Effective: March 1, 2026