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Alliant Energy Iowa rate increase

Electric & gas · Iowa · Investor-owned utility · part of Alliant Energy Corporation

Approved

Last checked

Alliant Energy Iowa's latest approved rate change: Residential natural gas rate cut after IUC review of the 2024 rate case. See the details below for what the sources say about bill impacts.

Details and sources

Rate changes, newest first

Residential natural gas rate cut after IUC review of the 2024 rate case

Other · Natural gas

Approved

Typical residential bill

Not stated for a specific usage level. Any figures the sources give are in the summary below.

Filed
Not disclosed
Decided
August 2026
Effective
Not disclosed
Requested increase
Not disclosed
Approved increase
Not disclosed
Docket
RPU-2023-0002

After the 2024 case raised gas base rates by $10 million a year (from Oct. 1, 2024), the IUC reviewed IPL's actual first-year results and in August 2026 ordered a permanent residential gas cut of $0.01886 per therm (over $2.5 million a year), with no refunds; a new tariff will set the start date. Electric rates were left unchanged, and the IUC opened a management probe (INU-2026-0002).

Utility's stated reasons

  • Actual gas earnings above the approved return range
  • Executive charter flights found inconsistent with settlement
Sources (4) · Based on news or utility announcements

Last verified Oct 12, 2026

Iowa electric rate increase from October 2024, then base rate freeze to September 2029

Base rate case · Electric

In effect

Typical residential bill

Not stated for a specific usage level. Any figures the sources give are in the summary below.

Filed
October 12, 2023
Decided
September 2024
Effective
October 1, 2024
Requested increase
$284 million
Approved increase
$185 million
Docket
RPU-2023-0002

Interstate Power and Light asked in October 2023 for about $284 million more in annual electric revenue. In September 2024 the IUC approved a settlement for $185 million with a 9.65% return on equity, effective Oct. 1, 2024; bill credits through a tax benefit rider softened the first 12 months. Electric base rates are then frozen from October 2025 through September 2029, with limited exceptions.

Utility's stated reasons

  • Solar generation investments
  • Updated depreciation rates
  • Costs from the 2020 derecho windstorm
Sources (4) · Verified against regulator or utility filings

Last verified Oct 12, 2026

Most recent base rate case

Decided September 2024 · Docket RPU-2023-0002

The IUC approved a settlement raising IPL's annual base revenue by $185 million for electric and $10 million for gas (9.65% return on equity), effective Oct. 1, 2024, followed by an electric base rate moratorium from October 2025 through September 2029.

Who decides

Utility website: www.alliantenergy.com

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Last checked Oct 12, 2026. Spotted something out of date? Tell us.