49 unchanged sentences
Prairie Creek Generating Station (Units 1 and 3);
−Removed: Cedar Rapids, IA 1958-1997 30
+Added: Cedar Rapids, IA (e) 1958-1997 37
Louisa Generating Station (Unit 1);
−Removed: Louisa, IA (e) 1983 30
+Added: Louisa, IA (f) 1983 30
Total Coal 711
1 unchanged sentence
Mason City, IA 1991 72
+Added: Lee Co., IA 2025 99
Energy Storage;
2 unchanged sentences
Total capacity 4,274
−Removed: Table of C o ntents
WPL Generating
4 unchanged sentences
West Riverside Energy Center (Units 1-3);
−Removed: Beloit, WI (f) 2020 387
+Added: Beloit, WI (g) 2020 390
Neenah Energy Facility (Units 1-2);
1 unchanged sentence
South Fond du Lac Combustion Turbines (2 Units);
−Removed: Fond du Lac, WI (g) 1994 163
+Added: Fond du Lac, WI (h) 1994 164
Total Gas 1,380
6 unchanged sentences
Forward Wind Energy Center (37 Units);
−Removed: Dodge and Fond du Lac Cos., WI (h) 2008 59
+Added: Dodge and Fond du Lac Cos., WI (i) 2008 59
Total Wind 480
16 unchanged sentences
Columbia Energy Center (Units 1-2);
−Removed: Portage, WI (i) 1975-1978 598
+Added: Portage, WI (j) 1975-1978 596
Edgewater Generating Station (Unit 5);
6 unchanged sentences
Total Hydro 19
+Added: Grant County, Grant Co., WI 2025 100
+Added: Wood County, Wood Co., WI 2025 75
Energy Storage;
6 unchanged sentences
(d) Represents IPL’s 28% ownership interest, which is operated by MidAmerican Energy Company.
−Removed: (e) Represents IPL’s 4% ownership interest, which is operated by MidAmerican Energy Company.
−Removed: (f) Represents WPL’s 56.6% ownership interest, which is operated by WPL.
−Removed: (g) Represents Units 2 and 3, which WPL owns.
+Added: (e) Subsequent to December 31, 2025, IPL retired Prairie Creek Unit 1 and fuel switched Prairie Creek Unit 3 to natural gas.
+Added: (f) Represents IPL’s 4% ownership interest, which is operated by MidAmerican Energy Company.
+Added: (g) Represents WPL’s 56.6% ownership interest, which is operated by WPL.
+Added: (h) Represents Units 2 and 3, which WPL owns.
WPL also operates, but does not own, South Fond du Lac Combustion Turbines Units 1 and 4.
−Removed: (h) Represents WPL’s 42.64% ownership interest, which is operated by Invenergy Services, LLC.
−Removed: (i) Represents WPL’s 53.5% ownership interest, which is operated by WPL.
+Added: (i) Represents WPL’s 42.64% ownership interest, which is operated by Invenergy Services, LLC.
+Added: (j) Represents WPL’s 53.5% ownership interest, which is operated by WPL.
IPL and WPL own overhead electric distribution line, underground electric distribution cable and substation distribution transformers, substantially all of which are located in Iowa for IPL and Wisconsin for WPL.
1 unchanged sentence
IPL’s and WPL’s gas distribution facilities include gas mains located in Iowa and Wisconsin, respectively.
−Removed: Table of C o ntents
−Removed: Other - IPL’s other property includes steam service assets.
−Removed: Refer to Note 9 for information regarding WPL’s lease of the Sheboygan Falls Energy Facility from AEF’s Non-utility Generation business.
+Added: Other - Refer to Note 9 for information regarding WPL’s lease of the Sheboygan Falls Energy Facility from AEF’s Non-utility Generation business.
Corporate Services - Corporate Services’ property included in “Property, plant and equipment, net” on Alliant Energy’s balance sheet at December 31, 2025 consisted primarily of computer software, and the corporate headquarters building located in Madison, Wisconsin.
4 unchanged sentences
a Mississippi River barge, rail and truck freight terminal in Illinois;
−Removed: wind turbine blade recycling services;
and a rail-served warehouse in Iowa.
1 unchanged sentence
Compared sentence by sentence after normalising whitespace, quotation marks, case and digits, so re-formatting and restated figures do not read as changed language. Wording changes appear as one removal and one addition. The current filing and the prior one are authoritative.