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Jointly-Owned Electric Utility Plant | 12 Months Ended
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Dec. 31, 2018
Jointly-Owned Electric Utility Plant | JOINTLY-OWNED ELECTRIC UTILITY PLANT Under joint ownership agreements with other utilities, IPL and WPL have undivided ownership interests in jointly-owned EGUs. Each of the respective owners is responsible for the financing of its portion of the construction costs. KWh generation and operating expenses are primarily divided between the joint owners on the same basis as ownership. IPL’s and WPL’s shares of expenses from jointly-owned EGUs are included in the corresponding operating expenses (e.g., electric production fuel, other operation and maintenance, etc.) in their income statements. Information relative to IPL’s and WPL’s ownership interest in these jointly-owned EGUs at December 31, 2018 was as follows (dollars in millions):
| Ownership |  | Electric |  | Accumulated Provision |  | Construction
| Interest % |  | Plant |  | for Depreciation |  | Work in Progress
IPL |  |  |  |  |  |  |
Ottumwa Unit 1 | 48.0 | % |  |  | $507.1 |  |  |  | $161.7 |  |  |  | $65.3 |
George Neal Unit 4 | 25.7 | % |  | 187.3 |  |  | 89.8 |  |  | 1.2 |
George Neal Unit 3 | 28.0 | % |  | 156.7 |  |  | 57.8 |  |  | 1.4 |
Louisa Unit 1 | 4.0 | % |  | 39.2 |  |  | 23.9 |  |  | 0.8 |
|  |  | 890.3 |  |  | 333.2 |  |  | 68.7 |
WPL |  |  |  |  |  |  |
Columbia Units 1-2 | 52.5 | % |  | 779.4 |  |  | 247.9 |  |  | 9.8 |
FWEC | 42.6 | % |  | 119.7 |  |  | 41.2 |  |  | 0.1 |
West Riverside (a) | 91.8 | % |  | — |  |  | — |  |  | 538.4 |
|  |  | 899.1 |  |  | 289.1 |  |  | 548.3 |
Alliant Energy |  |  |  | $1,789.4 |  |  |  | $622.3 |  |  |  | $617.0 |
(a) | In January 2018, certain electric cooperatives, which currently have wholesale power supply agreements with WPL, acquired a partial ownership interest in West Riverside.
IPL [Member] |
Jointly-Owned Electric Utility Plant | JOINTLY-OWNED ELECTRIC UTILITY PLANT Under joint ownership agreements with other utilities, IPL and WPL have undivided ownership interests in jointly-owned EGUs. Each of the respective owners is responsible for the financing of its portion of the construction costs. KWh generation and operating expenses are primarily divided between the joint owners on the same basis as ownership. IPL’s and WPL’s shares of expenses from jointly-owned EGUs are included in the corresponding operating expenses (e.g., electric production fuel, other operation and maintenance, etc.) in their income statements. Information relative to IPL’s and WPL’s ownership interest in these jointly-owned EGUs at December 31, 2018 was as follows (dollars in millions):
| Ownership |  | Electric |  | Accumulated Provision |  | Construction
| Interest % |  | Plant |  | for Depreciation |  | Work in Progress
IPL |  |  |  |  |  |  |
Ottumwa Unit 1 | 48.0 | % |  |  | $507.1 |  |  |  | $161.7 |  |  |  | $65.3 |
George Neal Unit 4 | 25.7 | % |  | 187.3 |  |  | 89.8 |  |  | 1.2 |
George Neal Unit 3 | 28.0 | % |  | 156.7 |  |  | 57.8 |  |  | 1.4 |
Louisa Unit 1 | 4.0 | % |  | 39.2 |  |  | 23.9 |  |  | 0.8 |
|  |  | 890.3 |  |  | 333.2 |  |  | 68.7 |
WPL |  |  |  |  |  |  |
Columbia Units 1-2 | 52.5 | % |  | 779.4 |  |  | 247.9 |  |  | 9.8 |
FWEC | 42.6 | % |  | 119.7 |  |  | 41.2 |  |  | 0.1 |
West Riverside (a) | 91.8 | % |  | — |  |  | — |  |  | 538.4 |
|  |  | 899.1 |  |  | 289.1 |  |  | 548.3 |
Alliant Energy |  |  |  | $1,789.4 |  |  |  | $622.3 |  |  |  | $617.0 |
(a) | In January 2018, certain electric cooperatives, which currently have wholesale power supply agreements with WPL, acquired a partial ownership interest in West Riverside.
WPL [Member] |
Jointly-Owned Electric Utility Plant | JOINTLY-OWNED ELECTRIC UTILITY PLANT Under joint ownership agreements with other utilities, IPL and WPL have undivided ownership interests in jointly-owned EGUs. Each of the respective owners is responsible for the financing of its portion of the construction costs. KWh generation and operating expenses are primarily divided between the joint owners on the same basis as ownership. IPL’s and WPL’s shares of expenses from jointly-owned EGUs are included in the corresponding operating expenses (e.g., electric production fuel, other operation and maintenance, etc.) in their income statements. Information relative to IPL’s and WPL’s ownership interest in these jointly-owned EGUs at December 31, 2018 was as follows (dollars in millions):
| Ownership |  | Electric |  | Accumulated Provision |  | Construction
| Interest % |  | Plant |  | for Depreciation |  | Work in Progress
IPL |  |  |  |  |  |  |
Ottumwa Unit 1 | 48.0 | % |  |  | $507.1 |  |  |  | $161.7 |  |  |  | $65.3 |
George Neal Unit 4 | 25.7 | % |  | 187.3 |  |  | 89.8 |  |  | 1.2 |
George Neal Unit 3 | 28.0 | % |  | 156.7 |  |  | 57.8 |  |  | 1.4 |
Louisa Unit 1 | 4.0 | % |  | 39.2 |  |  | 23.9 |  |  | 0.8 |
|  |  | 890.3 |  |  | 333.2 |  |  | 68.7 |
WPL |  |  |  |  |  |  |
Columbia Units 1-2 | 52.5 | % |  | 779.4 |  |  | 247.9 |  |  | 9.8 |
FWEC | 42.6 | % |  | 119.7 |  |  | 41.2 |  |  | 0.1 |
West Riverside (a) | 91.8 | % |  | — |  |  | — |  |  | 538.4 |
|  |  | 899.1 |  |  | 289.1 |  |  | 548.3 |
Alliant Energy |  |  |  | $1,789.4 |  |  |  | $622.3 |  |  |  | $617.0 |
(a) | In January 2018, certain electric cooperatives, which currently have wholesale power supply agreements with WPL, acquired a partial ownership interest in West Riverside.

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