XML 47 R17.htm IDEA: XBRL DOCUMENT
v3.25.0.1

Property, Plant and Equipment | 12 Months Ended
--- | ---
Dec. 31, 2024
Property, Plant and Equipment [Abstract] |
Property, Plant and Equipment | Property, Plant and Equipment Major classes of property, plant and equipment as of December 31, 2024 and 2023 include:
(in thousands) | 2024 |  | 2023
Electric Plant in Service |  |  |
Production | $ | 1,469,008 |  |  | $ | 1,412,826 |
Transmission | 820,415 |  |  | 777,613 |
Distribution | 726,159 |  |  | 654,704 |
General | 165,361 |  |  | 144,738 |
Electric Plant in Service | 3,180,943 |  |  | 2,989,881 |
Construction Work in Progress | 231,890 |  |  | 137,212 |
Total Gross Electric Plant | 3,412,833 |  |  | 3,127,093 |
Less Accumulated Depreciation | 899,049 |  |  | 851,148 |
Net Electric Plant | 2,513,784 |  |  | 2,275,945 |
Nonelectric Property, Plant and Equipment |  |  |
Equipment | 260,307 |  |  | 233,571 |
Buildings and Leasehold Improvements | 88,680 |  |  | 64,753 |
Land | 13,578 |  |  | 13,600 |
Nonelectric Property, Plant and Equipment | 362,565 |  |  | 311,924 |
Construction Work in Progress | 40,536 |  |  | 38,062 |
Total Gross Nonelectric Property, Plant and Equipment | 403,101 |  |  | 349,986 |
Less Accumulated Depreciation | 224,425 |  |  | 207,556 |
Net Nonelectric Property, Plant and Equipment | 178,676 |  |  | 142,430 |
Net Property, Plant and Equipment | $ | 2,692,460 |  |  | $ | 2,418,375 |
Depreciation expense for the years ended December 31, 2024, 2023 and 2022 totaled $99.4 million, $90.8 million and $84.4 million. The following table provides OTP’s ownership percentages and amounts included in the December 31, 2024 and 2023 consolidated balance sheets for OTP’s share of each of these jointly owned facilities:
(dollars in thousands) | Ownership Percentage |  | Electric Plant in Service |  | Construction Work in Progress |  | Accumulated Depreciation |  | Net Plant
December 31, 2024 |  |  |  |  |  |  |  |  |
Big Stone Plant | 53.9 | % |  | $ | 345,990 |  |  | $ | 459 |  |  | $ | (135,065) |  |  | $ | 211,384 |
Coyote Station | 35.0 | % |  | 188,066 |  |  | 813 |  |  | (118,268) |  |  | 70,611 |
Big Stone South–Ellendale 345 kV line | 50.0 | % |  | 106,185 |  |  | — |  |  | (8,445) |  |  | 97,740 |
Fargo–Monticello 345 kV line | 14.2 | % |  | 78,184 |  |  | — |  |  | (12,247) |  |  | 65,937 |
Big Stone South–Brookings 345 kV line | 50.0 | % |  | 53,167 |  |  | — |  |  | (5,822) |  |  | 47,345 |
Brookings–Southeast Twin Cities 345 kV line | 4.8 | % |  | 28,013 |  |  | 1,131 |  |  | (3,941) |  |  | 25,203 |
Bemidji–Grand Rapids 230 kV line | 14.8 | % |  | 16,331 |  |  | — |  |  | (3,693) |  |  | 12,638 |
Jamestown– Ellendale 345 kV line | 50.0 | % |  | — |  |  | 5,509 |  |  | — |  |  | 5,509 |
Big Stone South–Alexandria 345 kV line | 40.0 | % |  | — |  |  | 2,418 |  |  | — |  |  | 2,418 |
Alexandria–Big Oaks 345 kV line | 14.2 | % |  | — |  |  | 417 |  |  | — |  |  | 417 |
Oslo - Lake Ardoch 115 kV line | 72.0 | % |  | — |  |  | 2,646 |  |  | — |  |  | 2,646 |
December 31, 2023 |  |  |  |  |  |  |  |  |
Big Stone Plant | 53.9 | % |  | $ | 341,683 |  |  | $ | 820 |  |  | $ | (126,904) |  |  | $ | 215,599 |
Coyote Station | 35.0 | % |  | 188,656 |  |  | 104 |  |  | (115,306) |  |  | 73,454 |
Big Stone South–Ellendale 345 kV line | 50.0 | % |  | 106,185 |  |  | — |  |  | (7,181) |  |  | 99,004 |
Fargo–Monticello 345 kV line | 14.2 | % |  | 78,184 |  |  | — |  |  | (11,238) |  |  | 66,946 |
Big Stone South–Brookings 345 kV line | 50.0 | % |  | 53,170 |  |  | — |  |  | (5,207) |  |  | 47,963 |
Brookings–Southeast Twin Cities 345 kV line | 4.8 | % |  | 26,409 |  |  | 83 |  |  | (3,617) |  |  | 22,875 |
Bemidji–Grand Rapids 230 kV line | 14.8 | % |  | 16,331 |  |  | — |  |  | (3,568) |  |  | 12,763 |
Jamestown–Ellendale 345 kV line | 50.0 | % |  | — |  |  | 1,121 |  |  | — |  |  | 1,121 |
Big Stone South–Alexandria 345 kV line | 40.0 | % |  | — |  |  | 555 |  |  | — |  |  | 555 |
Alexandria–Big Oaks 345 kV line | 14.2 | % |  | — |  |  | 343 |  |  | — |  |  | 343 |

X
- References No definition available. + Details
Name: | us-gaap_PropertyPlantAndEquipmentAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The entire disclosure for long-lived, physical asset used in normal conduct of business and not intended for resale. Includes, but is not limited to, work of art, historical treasure, and similar asset classified as collections. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 360 -Name Accounting Standards Codification -Publisher FASB -URI https://asc.fasb.org/360/tableOfContent Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Name Accounting Standards Codification -Section 50 -Paragraph 6 -SubTopic 360 -Topic 958 -Publisher FASB -URI https://asc.fasb.org/1943274/2147477798/958-360-50-6 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (d) -SubTopic 360 -Topic 958 -Publisher FASB -URI https://asc.fasb.org/1943274/2147477798/958-360-50-1 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Name Accounting Standards Codification -Section 50 -Paragraph 7 -SubTopic 360 -Topic 958 -Publisher FASB -URI https://asc.fasb.org/1943274/2147477798/958-360-50-7 + Details
Name: | us-gaap_PropertyPlantAndEquipmentDisclosureTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration