20230929Tariff Advice Revision to Section C.pdf

September 29, 2023 Ms. Jan Noriyuki
Commission Secretary Idaho Public Utilities Commission P.O. Box 83720 Boise, ID 83720-0074

RE: Intermountain Gas Company Tariff Advice No. 23-03
Dear Ms. Noriyuki: Enclosed for filing with this Commission is a copy of Intermountain Gas Company’s (“Intermountain” or “Company”) proposed revisions to Section C of its General Service
Provisions. The proposed edits to Section C are presented in Attachment No. 1. The resulting
proposed Section C is presented in Attachment No. 2. The proposed revisions outlined below are in line with Commission Order No. 34735 in Case No. INT-G-20-01 which authorizes the Company to “file an annual tariff advice to update the
Allowable Investment Factors, the Service Line Cost per Foot, and the construction overhead
charge.” (See Order No. 34735 at 9.) In addition to these proposed revisions, the Company has also revised Attachment No. 3, pages 2-3 to reflect the updated embedded costs from the Company’s most recent general rate case in Case No. INT-G-22-07.
1. The update to the Allowable Investment Factors in Section 4.3 includes a change in
the compound inflation factor and an update to the embedded costs on pages 2-3 of Attachment No. 3 to reflect the most recent information from Case No. INT-G-22-07. The embedded costs update follows the same methodology approved by the Commission in Order No. 34735.

The compound inflation factor is updated to include inflation data for the first eight months of 2023. The Company adjusts for inflation of the embedded costs from its last general rate case to ensure that new applicants are treated the same as existing customers in terms of the amount of facilities for which their Allowable Investment
will pay. Case No. INT-G-22-07 included costs through the end of 2022 which is why
the Company’s adjustment begins with January 2023. The calculation of the proposed Allowable Investment Factors, including the
RECEIVED
2023 September 29, AM 10:18
IDAHO PUBLIC
UTILITIES COMMISSION
Tariff Advice Case No. INT-TAG-23-01
Intermountain Gas Company Page 2 of 2 Tariff Advice No. 23-03
adjustments discussed above, is shown in Attachment No. 3.
2.The update to its service line cost per foot in Section 5.2 is based on a new three-yearaverage of service line costs divided by the feet installed during the same years. The
proposed three-year average service line cost per foot is shown in Attachment No. 4.
3.The change in the construction overhead rate in Section 5.3(c) reflects theCompany’s currently calculated rate.
4. Finally, the Company has also provided clean tariffs as Attachment No. 5 should
the Commission approve the tariff revisions as filed.
The Company requests that the proposed revisions become effective one month after Commission approval to give the Company enough time to implement the changes to its systems and forms. Therefore, the Company proposes a Commission approval date of November 1, 2023,
and an effective date of December 1, 2023.
If you have any questions or require additional information regarding the attached, please contact me at [phone].
Sincerely,
/s/ Lori A. Blattner
Lori A. Blattner
Director – Regulatory Affairs Intermountain Gas Company
Enclosures
cc: Mark Chiles
Preston Carter
I.P.U.C. Gas Tariff
Section C
SixthSeventh Revised Sheet No. 4
Name
of Utility Intermountain Gas Company
Issued by: Intermountain Gas Company
By: Lori A. Blattner Title: Director – Regulatory Affairs
Natural Gas Appliances Annual Therm
Estimates
Ran e 23
Seasonal Fireplace 50
Grill 15
Clothes Dr er 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 0.65434 0.797698 1.451332
Commercial 0.475486 0.523593 1.0790.998
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 $14.0915.18 per foot.
Attachment No. 1
Tariff Advice No. 23-03 Intermountain Gas Company Page 1 of 2
I.P.U.C. Gas Tariff
Section C
FourthFifth Revised Sheet No. 5
Name
of Utility Intermountain Gas Company
Issued by: Intermountain Gas Company
By: Lori A. Blattner Title: Director – Regulatory Affairs
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 in the amount of 9.0010.97%.
(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.
Attachment No. 1
Tariff Advice No. 23-03 Intermountain Gas Company Page 2 of 2
I.P.U.C. Gas Tariff
Section C
Seventh Revised Sheet No. 4
Name
of Utility Intermountain Gas Company
Issued by: Intermountain Gas Company
By: Lori A. Blattner Title: Director – Regulatory Affairs
Natural Gas Appliances Annual Therm
Estimates
Ran e 23
Seasonal Fireplace 50
Grill 15
Clothes Dr er 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 0.654 0.797 1.451
Commercial 0.486 0.593 1.079
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 $15.18 per foot.
Attachment No. 2Tariff Advice No. 23-03 Intermountain Gas Company
Page 1 of 2
I.P.U.C. Gas Tariff
Section C
Fifth Revised Sheet No. 5
Name
of Utility Intermountain Gas Company
Issued by: Intermountain Gas Company
By: Lori A. Blattner Title: Director – Regulatory Affairs
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 in the amount of 10.97%.
(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.
Attachment No. 2Tariff Advice No. 23-03 Intermountain Gas Company
Page 2 of 2
Line No.Description Residential Commercial
(a)(b)(c)
1 Services Allowable Investment Factor
2 Service Line Extension Embedded Cost per Therm:
3 [1]0.041712$ 0.031019$
4 [2]0.002575 0.001915
5 Total 0.044287$ 0.032934$
6 Compound Inflation Factor[3]105.2%105.2%
7 Service Line Extension Embedded Cost per Therm (Line 5 times Line 6)0.046574$ 0.034635$
8 Weighted Asset Life:
9 [4]58 58
10 [1]0.041712$ 0.031019$
11 Weighting Factor (Line 9 times Line 10)2.419315 1.799122
12 [5]40 40
13 [2]0.002575$ 0.001915$
14 Weighting Factor (Line 12 times Line 13)0.103007 0.076601
15 Weighted Asset Life (Sum of Lines 11 and 14 divided by Line 5)57.0 57.0
16 Weighted Average Cost of Capital[6]6.97%6.97%
17 Services Allowable Investment Factor ($/therm)[7]0.654$ 0.486$
18 Mains Allowable Investment Factor
19 Main Line Extension Embedded Cost per Therm:
20 [8]0.000408$ 0.000304$
21 [9]0.050406 0.037485
22 [10]0.002557 0.001901
23 Total 0.053371$ 0.039690$
24 Compound Inflation Factor[3]105.2%105.2%
25 Main Line Extension Embedded Cost per Therm (Line 23 times Line 24)0.056127$ 0.041739$
26 Weighted Asset Life:
27 [11]56 56
28 [8]0.000408$ 0.000304$
29 Weighting Factor (Line 27 times Line 28)0.022865 0.017003
30 [12]70 70
31 [9]0.050406$ 0.037485$
32 Weighting Factor (Line 30 times Line 31)3.528446 2.623926
33 [13]43 43
34 [10]0.002557$ 0.001901$
35 Weighting Factor (Line 33 times Line 34)0.109937 0.081754
36 Weighted Asset Life (Sum of Lines 29, 32 and 35 divided by Line 23)68.6 68.6
37 Weighted Average Cost of Capital[6]6.97%6.97%
38 Mains Allowable Investment Factor ($/therm)[14]0.797$ 0.593$
NOTES
[6] Case No. INT-G-22-07, Stipulation and Settlement, Exhibit No. 1
[11] See Attachment No. 3, Page 3, Lines 2 and 12, Column (b)
[12] See Attachment No. 3, Page 3, Lines 4 and 14, Column (b)
[13] See Attachment No. 3, Page 3, Lines 5 and 15, Column (b)
[14] 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
[5] See Attachment No. 3, Page 3, Lines 9 and 19, Column (b)
[8] See Attachment No. 3, Page 3, Lines 2 and 12, Column (g)
[9] See Attachment No. 3, Page 3, Lines 4 and 14, Column (g)
[10] See Attachment No. 3, Page 3, Lines 5 and 15, Column (g)
[7] 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
INTERMOUNTAIN GAS COMPANY
Line Extension Allowable Investment Factors
[1] See Attachment No. 3, Page 3, Lines 6 and 16, Column (g)
[2] See Attachment No. 3, Page 3, Lines 9 and 19, Column (g)
[4] See Attachment No. 3, Page 3, Lines 6 and 16, Column (b)
[3] See Attachment No. 3, Page 4, Line 2, Column (n)
Attachment No. 3
Tariff Advice No. 23-03 Intermountain Gas Company Page 1 of 4
Line No.Description Total Company Residential Commercial
(a)(b)(c)(d)
1 Line Extension Costs Embedded in Current Rates
2 Case No. INT-G-22-07 Commission Ordered Depreciation[1]22,007,089$
3 Case No. INT-G-22-07 Commission Ordered Operating Income at 6.97%[1]26,854,614
4 Tax Gross-Up[1]9,392,938
5 Line Extension Embedded Costs (Sum of Lines 2 - 4)58,254,641$
6 Class Allocation of Line Extension Embedded Costs
7 Case No. INT-G-22-07 Proposed Distribution & Customer Rate Base[3]334,701,962$
8 Case No. INT-G-22-07 Commission Ordered Rate Base[1]385,288,577
9 Proposed Distribution Rate Base Percentage (Line 7 divided by Line 8)86.87%
10 Case No. INT-G-22-07 Class Base Revenue Requirement[2]73,360,477$ 26,811,471$
11 Case No. INT-G-22-07 Total Base Revenue Requirement[2]111,398,580 111,398,580
12 Class Base Revenue Requirement Percentage (Line 10 divided by Line 11)65.85%24.07%
13 Class Line Extension Embedded Costs[4]33,326,150$ 12,179,898$
NOTES
[1] Case No. INT-G-22-07, Stipulation and Settlement, Exhibit No. 1
[2]Case No. INT-G-22-07, Stipulation and Settlement, Exhibit No. 2
[3] Case No. INT-G-22-07, R. Amen Exhibit No. 2-Update, Page 32
INTERMOUNTAIN GAS COMPANY
Class Line Extension Embedded Costs
[4] Line 5, Column (b) times Line 9, Column (b) times Line 12 Columns (c) and (d), respectively.
Attachment No. 3
Tariff Advice No. 23-03 Intermountain Gas Company Page 2 of 4
Line No.Description
Total Company
Depreciation
[1]
Total Company
Distribution Plant in
[2]% by Account
Class Line Extension
Embedded Cost by
[3]
Class Billing
Determinants
[4]
Class Line Extension
Embedded Cost per Therm
[5]
(a)(b)(c)(d)(e)(f)(g)
1 Residential
2 FERC Account 374 - Dist Land & Land Rights 56 2,102,230$ 0.35%116,273$ 284,776,158 $0.000408
3 FERC Account 375 - Dist Structures & Improvements 53 96,343 0.02%5,329 284,776,158 $0.000019
4 FERC Account 376 - Dist Mains 70 259,532,576 43.07%14,354,531 284,776,158 $0.050406
5 FERC Account 378 - Dist Meas & Reg Sta Equip - Gen 43 13,163,797 2.18%728,079 284,776,158 $0.002557
6 FERC Account 380 - Dist Services 58 214,768,642 35.64%11,878,675 284,776,158 $0.041712
7 FERC Account 381 - Dist Meters 48 80,614,323 13.38%4,458,711 284,776,158 $0.015657
8 FERC Account 383 - Dist House Regulators 50 19,006,002 3.15%1,051,206 284,776,158 $0.003691
9 FERC Account 385 - Dist Ind Reg Sta 40 13,259,048 2.20%733,347 284,776,158 $0.002575
10 Total 602,542,961$ 100.00%33,326,150$
11 Commercial
12 FERC Account 374 - Dist Land & Land Rights 56 2,102,230$ 0.35%42,495$ 139,956,787 $0.000304
13 FERC Account 375 - Dist Structures & Improvements 53 96,343 0.02%1,947 139,956,787 $0.000014
14 FERC Account 376 - Dist Mains 70 259,532,576 43.07%5,246,232 139,956,787 $0.037485
15 FERC Account 378 - Dist Meas & Reg Sta Equip - Gen 43 13,163,797 2.18%266,095 139,956,787 $0.001901
16 FERC Account 380 - Dist Services 58 214,768,642 35.64%4,341,367 139,956,787 $0.031019
17 FERC Account 381 - Dist Meters 48 80,614,323 13.38%1,629,551 139,956,787 $0.011643
18 FERC Account 383 - Dist House Regulators 50 19,006,002 3.15%384,190 139,956,787 $0.002745
19 FERC Account 385 - Dist Ind Reg Sta 40 13,259,048 2.20%268,020 139,956,787 $0.001915
20 Total 602,542,961$ 100.00%12,179,898$
NOTES[1] Case No. INT-G-21-01, Stipulation and Settlement, Settlement Exhibit No. 1, Page 1, Lines 19-30, Column (m)
[2] Case No. INT-G-22-07, R. Amen Exhibit No. 2-Update, Page 23
[3] Column (d) times Attachment No. 3, Page 2, Line 13, Columns (c) and (d), respectively
Case No. INT-G-22-07,Stipulation and Settlement, Exhibit No. 3
Column (e) divided by Column (f)
Line Extension Embedded Cost per Therm by Distribution Account
INTERMOUNTAIN GAS COMPANY
Attachment No. 3
Tariff Advice No. 23-03 Intermountain Gas Company Page 3 of 4
Line No.Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Inflation Factor
(a)(b) (c) (d) (e)(f)(g) (h)(i)(j)(k)(l) (m)(n)
1 2023 5.6% 5.5% 5.6% 5.5% 5.3% 4.8% 4.7% 4.3%105.2%[2]
2 Compound Inflation Factor 105.2%[3]
NOTES
INTERMOUNTAIN GAS COMPANY
U.S. Inflation Data[1]
[1] Inflation data obtained from the Bureau of Labor Statistics website: https://data.bls.gov/timeseries/CUUR0000SA0L1E?output_view=pct_12mths
[2] One plus the average of Columns (b) - (m)
[3] Column (n), Line 1 times the inflation factor for each year since the last rate case
Attachment No. 3
Tariff Advice No. 23-03 Intermountain Gas Company Page 4 of 4
INTERMOUNTAIN GAS COMPANY
Average Cost per Foot for Service Lines
Line
No.Description 2019 2020 2021 Average
1 FERC Account 380 Additions 12,054,578.40$ 13,034,296.25$ 15,164,511.24$ 40,253,385.89$
2 Feet Installed 824,296 862,755 965,058 2,652,109
Cost/Foot
Attachment No. 4 Tariff Advice No. 23-03 Intermountain Gas Company Page 1 of 1
ATTACHMENT NO. 5
TARIFF ADVICE NO. 23-03
INTERMOUNTAIN GAS COMPANY
CLEAN TARIFFS
(2 pages)
I.P.U.C. Gas Tariff
Section C
Seventh Revised Sheet No. 4
Name
of Utility

Intermountain Gas Company

Issued by: Intermountain Gas Company
By: Lori A. Blattner Title: Director – Regulatory Affairs

Natural Gas Appliances Annual Therm
Estimates
Ran e 23
Seasonal Fireplace 50
Grill 15
Clothes Dr er 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 0.654 0.797 1.451
Commercial 0.486 0.593 1.079

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 $15.18 per foot.
I.P.U.C. Gas Tariff
Section C
Fifth Revised Sheet No. 5
Name
of Utility Intermountain Gas Company
Issued by: Intermountain Gas Company
By: Lori A. Blattner Title: Director – Regulatory Affairs
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 in the amount of 10.97%.
(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.