20211220IRP Exhibit 5.pdf

Intermountain Gas Company
Avoided Cost Model
Integrated Resource Plan 2021 – 2026

Exhibit No. 5

Line Nominal Cost Real Percent Real Cost Present Avoided Cost
No.Year
(a)(b)(c)(d)(e)(f)
1 2020 0.46$ 0.46$ 0.44$ 0.46$
2 2021 0.51 9.55%0.50 0.90 0.48
3 2022 0.57 8.57%0.55 1.37 0.50
4 2023 0.53 -7.67%0.50 1.79 0.50
5 2024 0.53 -2.27%0.49 2.18 0.50
6 2025 0.56 3.26%0.51 2.57 0.50
7 2026 0.58 1.42%0.52 2.94 0.50
8 2027 0.60 1.65%0.52 3.31 0.51
9 2028 0.62 0.64%0.53 3.66 0.51
10 2029 0.64 1.66%0.54 4.00 0.51
11 2030 0.66 1.61%0.54 4.33 0.51
12 2031 0.68 -0.14%0.54 4.64 0.51
13 2032 0.69 0.53%0.55 4.94 0.52
14 2033 0.72 2.40%0.56 5.24 0.52
15 2034 0.75 1.08%0.57 5.52 0.52
16 2035 0.77 1.27%0.57 5.80 0.52
17 2036 0.80 1.42%0.58 6.06 0.53
18 2037 0.81 -0.34%0.58 6.32 0.53
19 2038 0.83 0.48%0.58 6.56 0.53
20 2039 0.86 1.59%0.59 6.80 0.53
21 2040 0.87 -0.62%0.59 7.03 0.53
22 2041 0.90 0.51%0.59 7.24 0.53
23 2042 0.92 0.51%0.59 7.45 0.54
24 2043 0.94 0.51%0.60 7.65 0.54
25 2044 0.96 0.51%0.60 7.84 0.54
26 2045 0.99 0.52%0.60 8.02 0.54
27 2046 1.01 0.52%0.61 8.20 0.54
28 2047 1.04 0.52%0.61 8.37 0.54
29 2048 1.07 0.52%0.61 8.53 0.54
30 2049 1.09 0.52%0.62 8.69 0.54
Page 11, Line 4, Column (b).
Page 11, Line 5, Column (b).
INTERMOUNTAIN GAS COMPANY
Avoided Cost by Year
NOTES
1
Line Commodity Transportation Total
No.Year
(a)(b)(c)(d)(e)
1 2020 0.25$ -$ 0.21$ 0.46$
2 2021 0.30 - 0.21 0.51
3 2022 0.35 - 0.22 0.57
4 2023 0.31 - 0.22 0.53
5 2024 0.31 - 0.23 0.53
6 2025 0.33 - 0.23 0.56
7 2026 0.35 - 0.24 0.58
8 2027 0.36 - 0.24 0.60
9 2028 0.37 - 0.24 0.62
10 2029 0.39 - 0.25 0.64
11 2030 0.41 - 0.25 0.66
12 2031 0.42 - 0.26 0.68
13 2032 0.43 - 0.26 0.69
14 2033 0.45 - 0.27 0.72
15 2034 0.47 - 0.28 0.75
16 2035 0.49 - 0.28 0.77
17 2036 0.51 - 0.29 0.80
18 2037 0.52 - 0.29 0.81
19 2038 0.53 - 0.30 0.83
20 2039 0.56 - 0.30 0.86
21 2040 0.56 - 0.31 0.87
22 2041 0.58 - 0.32 0.90
23 2042 0.59 - 0.32 0.92
24 2043 0.61 - 0.33 0.94
25 2044 0.63 - 0.34 0.96
26 2045 0.65 - 0.34 0.99
27 2046 0.66 - 0.35 1.01
28 2047 0.68 - 0.36 1.04
29 2048 0.70 - 0.36 1.07
30 2049 0.72 - 0.37 1.09
to therms.
from Page 11, Line 4, Column (b).
INTERMOUNTAIN GAS COMPANY
Nominal Avoided Cost by Year
NOTES
2
Line Heating Weighted Basin HDD HDD Commodity
No.Year Month
(a)(b)(c)(d)(e)(f)
1 2020 10 2.14$ 3%0.07$
2 2020 11 2.32 8%0.19
3 2020 12 4.29 16%0.68
4 2020 1 3.47 20%0.69
5 2020 2 1.97 16%0.31
6 2020 3 1.54 15%0.22
7 2020 4 1.31 10%0.14
8 2020 5 1.59 7%0.11
9 2020 6 1.54 3%0.05
10 2020 7 1.51 1%0.02
11 2020 8 1.72 0%0.00
12 2020 9 2.39 1%0.01 2.50$
13 2021 10 2.46 3%0.08
14 2021 11 3.03 8%0.25
15 2021 12 3.17 16%0.50
16 2021 1 3.31 20%0.66
17 2021 2 2.76 16%0.44
18 2021 3 2.96 15%0.43
19 2021 4 2.44 10%0.25
20 2021 5 2.58 7%0.17
21 2021 6 2.75 3%0.09
22 2021 7 3.04 1%0.03
23 2021 8 3.24 0%0.00
24 2021 9 3.08 1%0.02 2.94$
25 2022 10 3.07 3%0.10
26 2022 11 3.35 8%0.27
27 2022 12 4.01 16%0.64
28 2022 1 4.04 20%0.80
29 2022 2 3.85 16%0.61
30 2022 3 3.07 15%0.45
31 2022 4 2.26 10%0.23
32 2022 5 2.00 7%0.13
33 2022 6 2.25 3%0.08
34 2022 7 2.52 1%0.03
35 2022 8 2.59 0%0.00
36 2022 9 2.60 1%0.02 3.37$
INTERMOUNTAIN GAS COMPANY
Commodity Cost
NOTES
3
Line Heating Weighted Basin HDD HDD Commodity
No.Year Month
(a)(b)(c)(d)(e)(f)
1 2023 10 2.57$ 3%0.09$
2 2023 11 2.91 8%0.24
3 2023 12 3.38 16%0.54
4 2023 1 3.43 20%0.68
5 2023 2 3.28 16%0.52
6 2023 3 2.80 15%0.41
7 2023 4 2.19 10%0.23
8 2023 5 1.95 7%0.13
9 2023 6 2.20 3%0.07
10 2023 7 2.37 1%0.02
11 2023 8 2.43 0%0.00
12 2023 9 2.54 1%0.02 2.95$
13 2024 10 2.49 3%0.08
14 2024 11 2.92 8%0.24
15 2024 12 3.16 16%0.50
16 2024 1 3.18 20%0.63
17 2024 2 3.05 16%0.49
18 2024 3 2.70 15%0.39
19 2024 4 2.29 10%0.24
20 2024 5 2.05 7%0.14
21 2024 6 2.33 3%0.08
22 2024 7 2.35 1%0.02
23 2024 8 2.43 0%0.00
24 2024 9 2.62 1%0.02 2.83$
25 2025 10 2.63 3%0.09
26 2025 11 2.93 8%0.24
27 2025 12 3.21 16%0.51
28 2025 1 3.34 20%0.66
29 2025 2 3.24 16%0.52
30 2025 3 3.01 15%0.44
31 2025 4 2.43 10%0.25
32 2025 5 2.32 7%0.15
33 2025 6 2.50 3%0.09
34 2025 7 2.54 1%0.03
35 2025 8 2.62 0%0.00
36 2025 9 2.72 1%0.02 2.99$
INTERMOUNTAIN GAS COMPANY
Commodity Cost
NOTES
4
Line Heating Weighted Basin HDD HDD Commodity
No.Year Month
(a)(b)(c)(d)(e)(f)
1 2026 10 2.75$ 3%0.09$
2 2026 11 3.05 8%0.25
3 2026 12 3.29 16%0.52
4 2026 1 3.37 20%0.67
5 2026 2 3.24 16%0.52
6 2026 3 2.96 15%0.43
7 2026 4 2.64 10%0.27
8 2026 5 2.52 7%0.17
9 2026 6 2.70 3%0.09
10 2026 7 2.74 1%0.03
11 2026 8 2.80 0%0.00
12 2026 9 2.90 1%0.02 3.07$
13 2027 10 2.93 3%0.10
14 2027 11 3.21 8%0.26
15 2027 12 3.40 16%0.54
16 2027 1 3.43 20%0.68
17 2027 2 3.28 16%0.52
18 2027 3 3.07 15%0.45
19 2027 4 2.71 10%0.28
20 2027 5 2.59 7%0.17
21 2027 6 2.78 3%0.09
22 2027 7 2.79 1%0.03
23 2027 8 2.87 0%0.00
24 2027 9 2.99 1%0.02 3.15$
25 2028 10 3.02 3%0.10
26 2028 11 3.29 8%0.27
27 2028 12 3.48 16%0.55
28 2028 1 3.47 20%0.69
29 2028 2 3.29 16%0.52
30 2028 3 3.09 15%0.45
31 2028 4 2.71 10%0.28
32 2028 5 2.57 7%0.17
33 2028 6 2.78 3%0.09
34 2028 7 2.81 1%0.03
35 2028 8 2.89 0%0.00
36 2028 9 3.00 1%0.02 3.18$
NOTES
Commodity Cost
INTERMOUNTAIN GAS COMPANY
5
Line Heating Weighted Basin HDD HDD Commodity
No.Year Month
(a)(b)(c)(d)(e)(f)
1 2029 10 3.03$ 3%0.10$
2 2029 11 3.31 8%0.27
3 2029 12 3.50 16%0.56
4 2029 1 3.62 20%0.72
5 2029 2 3.42 16%0.54
6 2029 3 3.18 15%0.46
7 2029 4 2.79 10%0.29
8 2029 5 2.69 7%0.18
9 2029 6 2.86 3%0.10
10 2029 7 2.88 1%0.03
11 2029 8 2.98 0%0.00
12 2029 9 3.07 1%0.02 3.27$
13 2030 10 3.11 3%0.10
14 2030 11 3.40 8%0.28
15 2030 12 3.58 16%0.57
16 2030 1 3.68 20%0.73
17 2030 2 3.52 16%0.56
18 2030 3 3.26 15%0.48
19 2030 4 2.88 10%0.30
20 2030 5 2.79 7%0.18
21 2030 6 2.95 3%0.10
22 2030 7 3.01 1%0.03
23 2030 8 3.10 0%0.00
24 2030 9 3.18 1%0.02 3.36$
25 2031 10 3.21 3%0.11
26 2031 11 3.48 8%0.29
27 2031 12 3.66 16%0.58
28 2031 1 3.64 20%0.73
29 2031 2 3.48 16%0.55
30 2031 3 3.22 15%0.47
31 2031 4 2.84 10%0.29
32 2031 5 2.73 7%0.18
33 2031 6 2.90 3%0.10
34 2031 7 2.95 1%0.03
35 2031 8 3.05 0%0.00
36 2031 9 3.13 1%0.02 3.35$
NOTES
INTERMOUNTAIN GAS COMPANY
Commodity Cost
6
Line Heating Weighted Basin HDD HDD Commodity
No.Year Month
(a)(b)(c)(d)(e)(f)
1 2032 10 3.16$ 3%0.11$
2 2032 11 3.38 8%0.28
3 2032 12 3.57 16%0.57
4 2032 1 3.73 20%0.74
5 2032 2 3.50 16%0.56
6 2032 3 3.31 15%0.48
7 2032 4 2.92 10%0.30
8 2032 5 2.83 7%0.19
9 2032 6 3.00 3%0.10
10 2032 7 3.03 1%0.03
11 2032 8 3.12 0%0.00
12 2032 9 3.22 1%0.02 3.38$
13 2033 10 3.26 3%0.11
14 2033 11 3.50 8%0.29
15 2033 12 3.69 16%0.59
16 2033 1 3.86 20%0.77
17 2033 2 3.67 16%0.58
18 2033 3 3.43 15%0.50
19 2033 4 3.05 10%0.32
20 2033 5 2.96 7%0.20
21 2033 6 3.14 3%0.11
22 2033 7 3.15 1%0.03
23 2033 8 3.26 0%0.00
24 2033 9 3.35 1%0.02 3.51$
25 2034 10 3.41 3%0.11
26 2034 11 3.66 8%0.30
27 2034 12 3.85 16%0.61
28 2034 1 3.88 20%0.77
29 2034 2 3.68 16%0.59
30 2034 3 3.46 15%0.50
31 2034 4 3.08 10%0.32
32 2034 5 2.99 7%0.20
33 2034 6 3.16 3%0.11
34 2034 7 3.18 1%0.03
35 2034 8 3.29 0%0.00
36 2034 9 3.38 1%0.02 3.57$
Commodity Cost
NOTES
INTERMOUNTAIN GAS COMPANY
7
Line Heating Weighted Basin HDD HDD Commodity
No.Year Month
(a)(b)(c)(d)(e)(f)
1 2035 10 3.43$ 3%0.11$
2 2035 11 3.69 8%0.30
3 2035 12 3.89 16%0.62
4 2035 1 3.96 20%0.79
5 2035 2 3.77 16%0.60
6 2035 3 3.56 15%0.52
7 2035 4 3.17 10%0.33
8 2035 5 3.04 7%0.20
9 2035 6 3.24 3%0.11
10 2035 7 3.24 1%0.03
11 2035 8 3.34 0%0.00
12 2035 9 3.49 1%0.02 3.64$
13 2036 10 3.51 3%0.12
14 2036 11 3.76 8%0.31
15 2036 12 3.97 16%0.63
16 2036 1 4.12 20%0.82
17 2036 2 3.82 16%0.61
18 2036 3 3.61 15%0.53
19 2036 4 3.22 10%0.33
20 2036 5 3.12 7%0.21
21 2036 6 3.29 3%0.11
22 2036 7 3.29 1%0.03
23 2036 8 3.39 0%0.00
24 2036 9 3.54 1%0.02 3.72$
25 2037 10 3.56 3%0.12
26 2037 11 3.85 8%0.32
27 2037 12 4.05 16%0.64
28 2037 1 4.11 20%0.82
29 2037 2 3.77 16%0.60
30 2037 3 3.52 15%0.51
31 2037 4 3.13 10%0.33
32 2037 5 3.04 7%0.20
33 2037 6 3.23 3%0.11
34 2037 7 3.22 1%0.03
35 2037 8 3.30 0%0.00
36 2037 9 3.46 1%0.02 3.70$
NOTES
INTERMOUNTAIN GAS COMPANY
Commodity Cost
8
Line Heating Weighted Basin HDD HDD Commodity
No.Year Month
(a)(b)(c)(d)(e)(f)
1 2038 10 3.48$ 3%0.12$
2 2038 11 3.83 8%0.31
3 2038 12 4.03 16%0.64
4 2038 1 4.08 20%0.81
5 2038 2 3.84 16%0.61
6 2038 3 3.61 15%0.53
7 2038 4 3.23 10%0.34
8 2038 5 3.09 7%0.20
9 2038 6 3.32 3%0.11
10 2038 7 3.31 1%0.03
11 2038 8 3.40 0%0.00
12 2038 9 3.56 1%0.02 3.73$
13 2039 10 3.57 3%0.12
14 2039 11 3.97 8%0.33
15 2039 12 4.13 16%0.66
16 2039 1 4.23 20%0.84
17 2039 2 3.91 16%0.62
18 2039 3 3.65 15%0.53
19 2039 4 3.27 10%0.34
20 2039 5 3.17 7%0.21
21 2039 6 3.39 3%0.12
22 2039 7 3.39 1%0.03
23 2039 8 3.46 0%0.00
24 2039 9 3.60 1%0.02 3.82$
25 2040 10 3.63 3%0.12
26 2040 11 4.00 8%0.33
27 2040 12 4.18 16%0.66
28 2040 1 4.09 20%0.82
29 2040 2 3.82 16%0.61
30 2040 3 3.61 15%0.53
31 2040 4 3.26 10%0.34
32 2040 5 3.21 7%0.21
33 2040 6 3.37 3%0.11
34 2040 7 3.39 1%0.03
35 2040 8 3.45 0%0.00
36 2040 9 3.57 1%0.02 3.79$
INTERMOUNTAIN GAS COMPANY
Commodity Cost
NOTES
9
Line Combined
No.Description RS GS-1 RS and GS-1
(a)(b)(c)(d)
1
2
3 RS and GS-1 Combined Gas Transportation Cost per Therm 0.17233$
4
5
6 RS and GS-1 Combined Gas Transportation Cost per Therm (0.00277)$
7 0.03937$
8 Total RS and GS-1 Combined Gas Transportation Cost per Therm 0.20893$
INTERMOUNTAIN GAS COMPANY
Avoided Gas Transportation Cost
NOTES
10
Line
No.Description Value Ratio Weighting W/Tax benefit
(a)(b)(c)(d)(e)
1
2
3 Weighted Average Cost of Capital 6.78%
4 Inflation Assumption 2.0%
5 Real Discount Rate 4.68%
NOTES
INTERMOUNTAIN GAS COMPANY
Discount Rate
11