Iowa · investor-owned utility
Alliant Energy (Interstate Power and Light): power factor rules
On Large General Service, demand charges rise once the power factor drops below 85%, with a bonus above 95%. Very large rates charge or credit per kVAR.
Power-factor rule confirmed Tariffs checked 2026-10-03
Smaller customers
General Service rates 600, 607 and 707 have no power-factor provision.
The power-factor rule
Large General Service rates 447/487
Applies to: More than 20,000 kWh for 12 consecutive months.
How it works: Where the power factor is below 85%, net demand charges increase by 0.1% for each 0.1% the power factor is below 90%. A bonus applies above 95%. Between 85% and 95% there is no adjustment.
Example: Illustration of our literal reading: at 84%, net demand charges rise 6% (counted from 90%). The tariff gives no worked example. Illustration, not a bill estimate; billed demand, measurement intervals, minimums and credits determine the actual adjustment.
"Where the power factor is less than 85%, the net demand charges will be increased by 1/10% for each 1/10% the power factor is below 90%"
Source: Interstate Power and Light Company Electric Tariff, Original Tariff No. 1, LGS Substitute Seventh Revised Sheet No. 27. Effective October 1, 2024. Checked 2026-10-03; review by 2027-10-03.
Not established Rate 760 High Load Factor / Large Volume
Applies to: Transmission-voltage service with minimum demand of 25,000 kW.
How it works: The research recorded a $1.78 per kilovar charge for reactive demand above 50% of kW and a credit below it, but we have not quoted the sheet text here, so treat this as unverified until checked. (kVAR = 50% of kW is about a 0.894 power factor; that equivalence is our calculation.)
Source: Interstate Power and Light Company Electric Tariff, Original Tariff No. 1, Rate 760, Substitute Eighth Revised Sheet No. 37. Effective October 1, 2024. Checked 2026-10-03; review by 2027-10-03.
Not established Supplementary Power 807/817; Rider ICR
Applies to: Not established on this page.
How it works: The research identifies a reactive-demand provision, but this page has not established the complete applicability and source details.
Source: Interstate Power and Light Company Electric Tariff, Original Tariff No. 1, Supplementary Power and Rider ICR sheets (not individually cited). not established. Checked 2026-10-03; review by 2027-10-03.
Caveats
- Copies were read from Alliant's site, not from the Iowa Utilities Commission filing system.
What to do next
- Size the kVAR for your load.
- Send us a bill and we'll tell you what you're paying and what correction is worth.
Cities we serve in Alliant Energy (Interstate Power and Light) territory
Tariffs change. This summary reflects the documents cited above as checked on 2026-10-03; your utility's current rate schedule and your bill govern what you pay.