20260930Tariff Advice No. INT-TAG-26-03 - Attachments 1-3.pdf

ATTACHMENT NO. 1
CASE NO. INT-TAG-26-03
INTERMOUNTAIN GAS COMPANY
REDLINE
TARIFF
(2 pages)

I.P.U.C. Gas Tariff IDAHO PUBLIC UTILITIES COMMISSION
Section C Approved Effective
NinlhTenth Revised Sheet No.4 October 28. 2025 December 1, 2025
Name Intermountain Gas Company Commission
of Utility p y Secretary
Natural Gas Appliances Annual Therm
Estimates
Range 23
Seasonal Fireplace 50
Grill 15
Clothes Dryer 28
Water Heater 240
(b) For commercial applicants:
The therm usage estimate will be determined by the Company on a case-by-case basis. The
estimate will be based on the climate zone,the heated structure square footage, commercial
property type, and applicable gas appliances.
4.3 To determine the Allowable Investment per applicant, multiply the estimated annual therm usage
per applicant by the applicable Allowable Investment Factor below to calculate the Allowable
Investment in dollars:
Allowable Investment Factors
Customer Type Service Main Combined
Residential 0.6-94806 0.8461.066 1.548872
Commercial 0.546553 0.629731 1.445284
4.4 The applicant agrees to install and activate gas appliances pursuant to the signed agreement(s)
and the therm usage estimates used to determine the Allowable Investment.
4.5 The Company may calculate the Allowable Investment for applicants with structures or business
operations which are non-permanent on a case-by-case basis.
5. PROJECT COST
5.1 In the event the Company can defray any of the trench and backfill costs,for example by sharing
a trench with other utilities, the cost reduction will be included in the Main extension cost or
Service cost estimates.
5.2 The Service Line Project Cost estimate is determined by multiplying the on-property Service Line
length by$49.7523.08 per foot.
Issued by: Intermountain Gas Company
By. Leri A. Bla t,o°~Michael Parvinen Title: Director—Regulatory Affairs

Gas Tariff
Section
C IDAHO PUBLIC UTILITIES COMMISSION
Secti
evepth^+" Ei hth Revised Sheet No. 5 Approved Effective
Name Intermountain Gas Company October 28, 2025 December 1. 2025
an
of Utility p y Commission Secretary
5.3 The Main Extension Project Cost estimate is based on the Gas Facilities (excluding Services)
required to serve the gas load of the requesting applicant. This includes but is not limited to
Main, regulator stations, valves and Main fittings.
(a) The Company will provide a Project Cost estimate to the applicant prior to execution of an
agreement.
(b) The estimate will exclude costs for Company Betterment.
(c) The Company includes construction overhead charges. On the a,,,,,, nt of 1 1 630
(d) The Main extension Project Cost will be divided by the number of estimated Service Points
to calculate the Main extension Project Cost per applicant.
6. OTHER PAYMENTS
6.1 The Company may require advanced payment from the applicant in the following situations:
(a) As a guarantee when proposed structures and Services are temporary in nature or the gas
load is unpredictable.
(b) When the Company conducts pre-construction engineering studies to improve the accuracy
of cost estimates.
6.2 If an advanced payment is collected according to Section 6.1(a), the Company will refund an
amount equal to the Allowable Investment to customers who meet the terms outlined in the
General Agreement for guaranteed usage. Refunds will not exceed the amount of the advanced
payment.
6.3 If an advanced payment is collected according to Section 6.1(b), and the actual cost of installation
is less than the estimated cost, the difference will be refunded to the customer.
7. VESTED INTEREST AND DEPOSIT REFUNDS
7.1 A customer or developer is eligible for refund of a payment made for Project Costs in excess of
the Allowable Investment for Mains when additional Service Points, not used in the original
calculation or in a previous refund calculation, connect to the Main extension within five years
from installation.
(a) The Company will conduct annual reviews to determine if additional customers have
connected to the Main and turned on gas service.
(b) Intermountain will take the steps outlined in Section 4 to calculate the Allowable Investment
for Mains for each additional customer.
(c) The Company will refund to the original applicant or developer the equivalent of the Allowable
Investment for Mains for each additional customer. Refunds will be made up to the total
upfront payment, but not to exceed the Project Cost in excess of Allowable Investment for
Mains.
Issued by: Intermountain Gas Company
By. Leri A. Bla t,o°~Michael Parvinen Title: Director—Regulatory Affairs

ATTACHMENT NO. 2
CASE NO. INT-TAG-26-03
INTERMOUNTAIN GAS COMPANY
CLEAN
TARIFF
(2 pages)

I.P.U.C. Gas Tariff
Section C
Tenth Revised Sheet No.4
Name Intermountain Gas Company
of Utility
Natural Gas Appliances Annual Therm
Estimates
Range 23
Seasonal Fireplace 50
Grill 15
Clothes Dryer 28
Water Heater 240
(b) For commercial applicants:
The therm usage estimate will be determined by the Company on a case-by-case basis. The
estimate will be based on the climate zone, the heated structure square footage, commercial
property type, and applicable gas appliances.
4.3 To determine the Allowable Investment per applicant, multiply the estimated annual therm usage
per applicant by the applicable Allowable Investment Factor below to calculate the Allowable
Investment in dollars:
Allowable Investment Factors
Customer Type Service Main Combined
Residential 0.806 1.066 1.872
Commercial 0.553 0.731 1.284
4.4 The applicant agrees to install and activate gas appliances pursuant to the signed agreement(s)
and the therm usage estimates used to determine the Allowable Investment.
4.5 The Company may calculate the Allowable Investment for applicants with structures or business
operations which are non-permanent on a case-by-case basis.
5. PROJECT COST
5.1 In the event the Company can defray any of the trench and backfill costs, for example by sharing
a trench with other utilities, the cost reduction will be included in the Main extension cost or
Service cost estimates.
5.2 The Service Line Project Cost estimate is determined by multiplying the on-property Service Line
length by$23.08 per foot.
Issued by: Intermountain Gas Company
By: Michael Parvinen Title: Director—Regulatory Affairs

IRILI.C. Gas Tariff
Section C
Eighth Revised Sheet No. 5
Name Intermountain Gas Company
of Utility
5.3 The Main Extension Project Cost estimate is based on the Gas Facilities (excluding Services)
required to serve the gas load of the requesting applicant. This includes but is not limited to
Main, regulator stations, valves and Main fittings.
(a) The Company will provide a Project Cost estimate to the applicant prior to execution of an
agreement.
(b) The estimate will exclude costs for Company Betterment.
(c) The Company includes construction overhead charges.
(d) The Main extension Project Cost will be divided by the number of estimated Service Points
to calculate the Main extension Project Cost per applicant.
6. OTHER PAYMENTS
6.1 The Company may require advanced payment from the applicant in the following situations:
(a) As a guarantee when proposed structures and Services are temporary in nature or the gas
load is unpredictable.
(b) When the Company conducts pre-construction engineering studies to improve the accuracy
of cost estimates.
6.2 If an advanced payment is collected according to Section 6.1(a), the Company will refund an
amount equal to the Allowable Investment to customers who meet the terms outlined in the
General Agreement for guaranteed usage. Refunds will not exceed the amount of the advanced
payment.
6.3 If an advanced payment is collected according to Section 6.1(b),and the actual cost of installation
is less than the estimated cost, the difference will be refunded to the customer.
7. VESTED INTEREST AND DEPOSIT REFUNDS
7.1 A customer or developer is eligible for refund of a payment made for Project Costs in excess of
the Allowable Investment for Mains when additional Service Points, not used in the original
calculation or in a previous refund calculation, connect to the Main extension within five years
from installation.
(a) The Company will conduct annual reviews to determine if additional customers have
connected to the Main and turned on gas service.
(b) Intermountain will take the steps outlined in Section 4 to calculate the Allowable Investment
for Mains for each additional customer.
(c) The Company will refund to the original applicant or developer the equivalent of the Allowable
Investment for Mains for each additional customer. Refunds will be made up to the total
upfront payment, but not to exceed the Project Cost in excess of Allowable Investment for
Mains.
Issued by: Intermountain Gas Company
By: Michael Parvinen Title: Director—Regulatory Affairs

ATTACHMENT NO. 3
CASE NO. INT-TAG-26-03
INTERMOUNTAIN GAS COMPANY
ALLOWABLE
INVESTMENT
CALCULATIONS
(5 pages)

Attachment No.3
Case No.INT-TAG-26-03
Intermountain Gas Company
Page 1 of 5
INTERMOUNTAIN GAS COMPANY
Line Extension Allowable Investment Factors
Line No. Description Residential Commercial
(a) (b) (c)
1 Services Allowable Investment Factor
2 Service Line Extension Embedded Cost per Therm:
3 FERC Account3801't $ 0.055134 $ 0.037808
4 FERC Account385121 0.002599 0.001783
5 Total $ 0.057734 $ 0.039590
6 Compound Inflation Factori'l 102.6% 102.6%
7 Service Line Extension Embedded Cost per Therm(Line 5 times Line 6) $ 0.059235 $ 0.040619
8 Weighted Asset Life:
9 FERC Account 380-Asset Lifel4t 60 60
10 FERC Account 380-Embedded Cost per Therm"' $ 0.055134 $ 0.037808
11 Weighting Factor(Line 9 times Line 10) 3.308061 2.268455
12 FERC Account 385-Asset Lifel8l 42 42
13 FERC Account 385-Embedded Cost per Therm l2, $ 0.002599 $ 0.001783
14 Weighting Factor(Line 12 times Line 13) 0.109177 0.074866
15 Weighted Asset Life(Sum of Lines 11 and 14 divided by Line 5) 59.2 59.2
16 Weighted Average Cost of Capitalist 7.23% 7.23
17 Services Allowable Investment Factor($/therr i $ 0.806 $ 0.553
18 Mains Allowable Investment Factor
19 Main Line Extension Embedded Cost per Therm:
20 FERC Account374181 $ 0.000319 $ 0.000218
21 FERC Account37619t 0.071949 0.049338
22 FERC Account3781'0t 0.003400 0.002331
23 Total $ 0.075668 $ 0.051888
24 Compound Inflation Factor131 102.6% 102.6%
25 Main Line Extension Embedded Cost per Therm(Line 23 times Line 24) $ 0.077635 $ 0.053237
26 Weighted Asset Life:
27 FERC Account 374-Asset Life"t 65 65
28 FERC Account 374-Embedded Cost perThermtet $ 0.000319 $ 0.000218
29 Weighting Factor(Line 27 times Line 28) 0.020710 0.014202
30 FERC Account 376-Asset Life1121 71 71
31 FERC Account 376-Embedded Cost per ThermEs $ 0.071949 $ 0.049338
32 Weighting Factor(Line 30 times Line 31) 5.108378 3.502997
33 FERC Account 378-Asset Wel1s] 45 45
34 FERC Account 378-Embedded Cost per Therm""' $ 0.003400 $ 0.002331
35 Weighting Factor(Line 33 times Line 34) 0.152997 0.104915
36 Weighted Asset Life(Sum of Lines 29,32 and 35 divided by Line 23) 69.8 69.8
37 Weighted Average Cost of Capitalist 7.23% 7.23
38 Mains Allowable Investment Factor($/therm)l'41 $ 1.066 $ 0.731
NOTES
I']See Attachment No.3,Page 3,Lines 7 and 19,Column(g)
IZt See Attachment No.3,Page 3,Lines 10 and 22,Column(g)
I']See Attachment No.3,Page 4,Line 2,Column(n)
141 See Attachment No.3,Page 3,Lines 7 and 19,Column(b)
I't See Attachment No.3,Page 3,Lines 10 and 22,Column(b)
Ist Case No.INT-G-25-02,Stipulation and Settlement,Exhibit No.1
In The present value of Line 7 discounted by the weighted average cost of capital on Line 16 over the weighted life of
the assets on Line 15
let See Attachment No.3,Page 3,Lines 2 and 14,Column(g)
I91 See Attachment No.3,Page 3,Lines 4 and 16,Column(g)
Eml See Attachment No.3,Page 3,Lines 5 and 17,Column(g)
l"t See Attachment No.3,Page 3,Lines 2 and 14,Column(b)
l'ZI See Attachment No.3,Page 3,Lines 4 and 16,Column(b)
173t See Attachment No.3,Page 3,Lines 5 and 17,Column(b)
I'41 The present value of Line 25 discounted by the weighted average cost of capital on Line 37 over the weighted life
of the assets on Line 36

Attachment No.3
Case No.INT-TAG-26-03
Intermountain Gas Company
Page 2 of 5
INTERMOUNTAIN GAS COMPANY
Class Line Extension Embedded Costs
Line No. Description Total Company Residential Commercial
(a) (b) (c) (d)
1 Line Extension Costs Embedded in Current Rates
2 Case No.INT-G-25-02 -Depreciation(see line 21) $ 27,731,374
3 Case No.INT-G-25-02 -Operating Income at 7.23%111 37,941,092
4 Tax Gross-Up[" 13,032,006
5 Line Extension Embedded Costs(Sum of Lines 2-4) $ 78,704,472
6 Class Allocation of Line Extension Embedded Costs
7 Case No.INT-G-25-02-Distribution&Customer Rate Base(sum of line 29&32) $ 485,506,689
8 Case No.INT-G-25-02-Rate Base[" 524,773,059
9 Proposed Distribution Rate Base Percentage(Line 7 divided by Line 8) 92.52%
10 Case No.INT-G-25-02-Class Base Revenue Requirementl2l $ 90,489,383 $ 29,800,424
11 Case No.INT-G-25-02-Total Base Revenue Requirementl2l 132,595,341 132,595,341
12 Class Base Revenue Requirement Percentage(Line 10 divided by Line 11) 68.24% 22.47%
13 Class Line Extension Embedded Costsl3l $ 49,692,685 $ 16,365,048
14 Derivation of Settled Depreciation Expense
15 Case No.INT-G-25-02-Proposed Net Operating Income Before Adjustment[" $ 25,743,472
16 Case No.INT-G-25-02-Net Operating Income Settlement Adjustment[" 2,521,257
17 Case No.INT-G-25-02-Settled Net Operating Income[" $ 28,264,729
18 %Settlement Adjustment of Proposed Net Operating Income Before Adjustment 9.79%
19 Case No.INT-G-25-02-Proposed Depreciation Expense Before Adjustment,<, $ 30,742,195
20 Case No.INT-G-25-02-Derived Depreciation Expense Settlement Adjustment (3,010,821)
21 Case No.INT-G-25-02-Derived Settled Depreciation Expense $ 27,731,374
22 Derivation of Settled Distribution&Customer Rate Base
23 Case No.INT-G-25-02-Proposed Total Rate Base Before Adjustment[" $ 578,473,094
24 Case No.INT-G-25-02-Total Rate Base Settlement Adjustment[" (53,700,035)
25 Case No.INT-G-25-02-Settled Total Rate Base[" $ 524,773,059
26 %Settlement Adjustment of Proposed Total Rate Base Before Adjustment -9.28%
27 Case No.INT-G-25-02-Proposed Distribution Rate Base Before Adjustmentj51 $ 262,641,841
28 Case No.INT-G-25-02-Derived Distribution Rate Base Settlement Adjustment (24,381,214)
29 Case No.INT-G-25-02-Derived Settled Distribution Rate Base $ 238,260,627
30 Case No.INT-G-25-02-Proposed Customer Rate Base Before Adjustment[', $ 272,546,755
31 Case No.INT-G-25-02-Derived Customer Rate Base Settlement Adjustment (25,300,693)
32 Case No.INT-G-25-02-Derived Customer Rate Base $ 247,246,062
NOTES
Ill Case No.INT-G-25-02,Stipulation and Settlement,Exhibit No.1
121 Case No.INT-G-25-02,Stipulation and Settlement,Exhibit No.2
131 Line 5,Column(b)times Line 9,Column(b)times Line 12 Columns(c)and(d),respectively.
141 Case No.INT-G-25-02,Exhibit No.30,Line 16,Column(d)

E¢cam
¢i5
U
C O V V M W N rn 0
m O O W^O O O O O O O O O O O O M c 0 0 0 H O O
N 4YJ -KO---OM---ON --------ON-
W O U O
c U Q
m m
m�
U E
E
N N N N N N
. . . . . . . . . . . . . . . . . . . .
rn�_ rnm rnm rnrn rnrn rn Sim Sim mm mm mm
N N N N N N
mE M m M m M OM M M M M V>C
Up yy
0 a N N E yy V(V M th N 1�N M c0�V M N lV N V N N
m m °u
f01 U W
V
C
O y
• .- N O cD�N N��O�0 0 N�N�N N�tD�O O O
ao
T
r
C h 0 aD th�M r M N V
y Z E a m V N N(OD N M NOi fM0 N V N N f00 W M N fM0 C N N N n W
O NM Mro r m V N N(Op Oro M N
N N N tpIli
M O N
- tp Np Oi M -N N N N NO A-7`N> N
U (n M c N th N c N n M N I
a o �o
Z Q _ U
pa m� R
6 E o
�j cc u>�aacov urnivm co vrni�aemaNaM d
Z E F Q a d
m
a
.yO
- d
G7 Z
x E _ 1.
W -
w
J d d M m m
E ?Z
v� -
o a
C7 Um Um m t
v
E E E .5.5 E I"� E � � E E �"� E
_o w w - w w - c ` w w - -
o�` m m ' rn` m m �' 2- E rn m m 'n c a E m m o
c N E N(n W (n fn W = ; E (n N W f E fn(n m w M LL O
o v m rn m 5 op i�n. of ep Nm 2o a=y n'o t� eti of ywm y c oD e6M3 L° ayN U `o Z od
of 02
.�oof x m
° ZO
! m nrw0 oM I N Nm Mt x'o N M Ny x E N
. ci C
U
O O O a O D O O O O O 0 0 y a O O O O 0 0 E a p O O O O O N 4 a
y p i i 'RC,
M n M M M M M M M n M M M M M M M M M m M M n M M M M M M M p M n M M M n�i M n�i M M 0 CD N CD"O
N Q Z Z Z
m38383 � 3 ' u � s33338380. � 3 0° 8383 � 3 � 3R8 E � 33383 � 3 � ° 8 z° z° 9z°V
y Q Q Q Q Q Q Q Q Q Q d Q Q Q Q Q Q Q Q Q Q N Q Q Q Q Q Q Q Q Q Q m Q Q Q Q Q Q Q Q Q Q f/1 m m j m j
E U U U U U j U U U U U U U U U U- w N N O N co
¢ m E m m m r
w w w w w w w w w w w o c w w w w w w w w w w o m °w w w w w w w w w w o d w w w w w w w w w w o O D U U U
C LL LL LL LL LL LL LL LL LL LL F U LL LL LL LL LL LL LL LL LL LL F O LL LL LL LL LL LL LL LL LL LL LL H a ❑LL LL LL LL LL LL LL LL LL LL f 2=. C
O
Z N M N N W rn N'N N a N N N N M'M M M M M
N N N M V V V V V V V V V V h

\\�\
)\\
;\
)\ ) e e
2f
) 2
W
\
2 Eq
_ \
< , �
a >
�
0
Q
Cli
Q
/ \ \
\ 4- / ® C-4 \
P-z
D )
0 $
) * ~ E
w
CD
R _
2
CD
LL \ \
( \ )
\ / P
} ( 2
LL i3f
2 a) k
N0 \ a \
/ { |
zj
//

. O C 0
O O
Z N ELO
Q Uco
E CL
m
m Z U
— c
Q00
O 'm
Z c 0) It O
ch
U E 00 � N
m 16
N 4% LO CCT ti
Q00 ti
� LO
00 ti
M 4
,tt N
.-. M (0
N v O
00
ER ER
cM
U) N 0) M
� - 00 N
Z J M 00 W
IL V CD N 00 Cfl
N
O a�
U
Q
°
z O a, ti 00
LL 00 00 m
Zm
Q LO 00 N
a+ N It LO
O N CD00
0 N v M
00
LU 4
Z
_ N
Q
C
O
C
O O a p
Q CY) ca O
U) LL
C:
O
O
Q LL
U
ry
LU
LL
C
Z
N N ce)
C
J