Interstate Power and Light Co
Investor Owned electric utility · Iowa · #77 of 3,199 U.S. utilities by customers · EIA utility #9417
Interstate Power and Light Co is a investor owned electric utility serving 506,498 customers in Iowa. In 2025 it sold 13,913 gigawatt-hours of electricity for $1.81B in revenue, an average realized rate of 13.03¢ per kWh across all customer classes and 17.77¢ per kWh for residential customers. Its reported service territory covers 84 counties. EIA records its activities as: generation, buying transmission, distribution, buying distribution, wholesale marketing.
Customers, sales and rates by customer class (2025)
| Class | Customers | Sales (GWh) | Revenue | Avg realized rate | Share of sales |
|---|---|---|---|---|---|
| Residential | 419,451 | 3,722 | $661.27M | 17.77¢ | |
| Commercial | 85,846 | 4,127 | $621.32M | 15.05¢ | |
| Industrial | 1,201 | 6,065 | $530.61M | 8.75¢ | |
| Total | 506,498 | 13,913 | $1.81B | 13.03¢ |
Average realized rate = revenue divided by sales as reported on EIA Form 861. It blends fixed charges, demand charges and riders into one per-kWh figure; it is not the utility's tariff rate. Estimated residential bill assumes the average residential customer's actual 2025 usage (739 kWh/month).
Five-year trend
| Year | Customers | Sales (GWh) | Revenue | Residential rate |
|---|---|---|---|---|
| 2021 | 497,289 | 14,318 | $1.65B | 16.84¢ |
| 2022 | 499,378 | 14,303 | $1.76B | 17.75¢ |
| 2023 | 501,812 | 13,940 | $1.67B | 17.86¢ |
| 2024 | 504,146 | 13,652 | $1.67B | 17.90¢ |
| 2025 | 506,498 | 13,913 | $1.81B | 17.77¢ |
Reliability (2025)
Average outage time (SAIDI): 88 minutes per customer per year
Average outages (SAIFI): 0.82 per customer
Average restoration time (CAIDI): 108 minutes
As reported for Iowa under the Other standard, with major event days included where the standard reports them. Lower is better; see the reliability rankings.
Energy supply (2025)
Net generation: 13,274 GWh
Wholesale power purchased: 4,258 GWh
Winter peak demand: 2,433 MW
Energy losses: 1.5% of energy handled
Meters & rooftop solar (2025)
Smart (AMI) meters: 99.0% of 500,871 meters
Customer-sited generation (net metering): 15,878 installations, 236.1 MW of capacity
Counties served
Adair, IAAdams, IAAllamakee, IAAppanoose, IABenton, IABlack Hawk, IABoone, IABremer, IABuchanan, IABuena Vista, IAButler, IACarroll, IACass, IACedar, IACerro Gordo, IACherokee, IAChickasaw, IAClarke, IAClay, IAClayton, IAClinton, IADallas, IADavis, IADecatur, IADelaware, IADes Moines, IADickinson, IADubuque, IAEmmet, IAFayette, IAFloyd, IAFranklin, IAGreene, IAGrundy, IAGuthrie, IAHamilton, IAHancock, IAHardin, IAHenry, IAHoward, IAIowa, IAJackson, IAJasper, IAJefferson, IAJohnson, IAJones, IAKeokuk, IAKossuth, IALee, IALinn, IALouisa, IALucas, IALyon, IAMadison, IAMahaska, IAMarion, IAMarshall, IAMitchell, IAMonroe, IAMontgomery, IA + 24 more counties
Other large utilities in Iowa
- MidAmerican Energy Co - 838,069 customers, residential 11.08¢
- Corridor Energy Cooperative - 35,447 customers, residential 14.18¢
- City of Ames - (IA) - 28,239 customers, residential 12.12¢
- Eastern Iowa Light & Power Coop - 23,856 customers, residential 14.81¢
- Cedar Falls Utilities - 20,245 customers, residential 11.56¢
- Maquoketa Valley Rrl Elec Coop - 17,339 customers, residential 13.80¢
- Iowa Lakes Electric Coop - 13,257 customers, residential 13.78¢
- Midland Power Coop - 12,708 customers, residential 13.66¢
Source: U.S. Energy Information Administration, Form EIA-861 2025 (filed by the utility; figures as published). Utility #9417 in the EIA frame.