States › Illinois › Rock Energy Cooperative
electric cooperative · EIA utility 16196
Rock Energy Cooperative
Average price is revenue divided by sales for the sector and year; it is not a tariff rate. Reliability figures are as reported by utilities to EIA on Form 861 and may use different calculation methods. Annual figures: Form EIA-861 for 2024, final release. Monthly state figures run to July 2026.
Rock Energy Cooperative serves 16,649 residential customers in Illinois and 1 other state as an electric cooperative, according to its 2024 Form EIA-861 filing, with a service territory that touches 8 counties.
Its average residential price that year was 14.72¢ per kilowatthour, 7.2% below the Illinois average of 15.87¢ and 11% below the US average of 16.48¢. The figure is residential revenue divided by residential sales, so it folds in fixed charges, riders and every rate schedule the utility bills under.
That works out to an average residential bill of $123.21 a month on average use of 837 kWh a month. Across Illinois the average bill was $109.99 on 693 kWh, so a bill gap reflects how much power households use as well as what each kilowatthour costs.
For reliability it reported a SAIDI of 47.0 minutes per customer with major event days included and 24.9 minutes with them excluded, calculated under IEEE 1366 standard. The median among Illinois utilities reporting was 131.9 minutes with major event days; this utility's figure is 64% below that median.
The average price is up 10.3% on 2019, against up 21.8% for Illinois as a whole, and up 2.4% on 2023. EIA's early release for 2025, which has not been fully edited, shows 14.58¢.
Compared with Illinois, the US and other electric cooperatives
| Measure, 2024 | This utility | Electric cooperatives, US median | Illinois | United States |
|---|---|---|---|---|
| Average residential price per kWh | 14.72¢ | 13.74¢ | 15.87¢ | 16.48¢ |
| Average monthly residential bill | $123.21 | $149.95 | $109.99 | $142.26 |
| Average monthly use, kWh | 837 | 1,126 | 693 | 863 |
| Residential price change, 1 year | +2.4% | — | +1.0% | +3.0% |
| Residential price change, 5 years | +10.3% | — | +21.8% | +26.7% |
| SAIDI, all events (minutes) | 47.0 | 263.0 | 131.9 median | 184.5 median |
| SAIDI, without major event days | 24.9 | 147.0 | 85.0 median | 99.8 median |
State and US prices, bills and use are EIA's own averages over every customer. The ownership column and the reliability columns are medians across utilities with at least 1,000 residential customers, computed on this site from the final 2024 file. Among the 14 filings by electric cooperatives in Illinois, the median price was 16.04¢. In Illinois this utility's price ranks 15 of 24, counting from the highest.
Average price by year
Rock Energy CooperativeIllinois averageUS average
Year by year
| Year | ¢ per kWh | Illinois ¢ | Monthly bill | kWh a month | Residential customers | All sales |
|---|---|---|---|---|---|---|
| 2025 early release | 14.58¢ | 17.69¢ | $125.43 | 860 | 16,830 | 533.6 GWh |
| 2024 | 14.72¢ | 15.87¢ | $123.21 | 837 | 16,649 | 524.1 GWh |
| 2023 | 14.37¢ | 15.71¢ | $120.56 | 839 | 16,631 | 524.1 GWh |
| 2022 | 13.97¢ | 15.65¢ | $119.79 | 858 | 16,558 | 537.7 GWh |
| 2021 | 12.88¢ | 13.18¢ | $112.52 | 873 | 16,411 | 547.2 GWh |
| 2020 | 13.03¢ | 13.04¢ | $112.53 | 863 | 16,315 | 518.9 GWh |
| 2019 | 13.35¢ | 13.03¢ | $112.88 | 846 | 16,218 | 531.4 GWh |
| 2018 | 13.21¢ | 12.77¢ | $115.14 | 871 | 16,130 | 522.1 GWh |
| 2017 | 13.34¢ | 12.95¢ | $110.15 | 825 | 16,043 | 526.1 GWh |
| 2016 | 12.78¢ | 12.54¢ | $111.16 | 870 | 15,937 | 512.9 GWh |
| 2015 | 12.78¢ | 12.50¢ | $107.87 | 844 | 15,843 | 505.7 GWh |
| 2014 | 12.19¢ | 11.91¢ | $106.49 | 874 | 15,777 | 495.5 GWh |
| 2013 | 11.55¢ | 10.63¢ | $101.53 | 879 | 15,750 | 497.7 GWh |
Bundled residential service only in the price, bill and use columns. Bill = residential revenue ÷ customers ÷ 12; use = residential sales ÷ customers ÷ 12. EIA describes its early release as not fully edited; it is shown for this utility alone and enters no average, median or rank on this site.
Sales by sector, 2024
| Sector | Customers | Sales | Share of sales | Revenue | ¢ per kWh, bundled |
|---|---|---|---|---|---|
| Residential | 16,649 | 167.3 GWh | 32% | $24,616,000 | 14.72¢ |
| Commercial | 1,422 | 141.4 GWh | 27% | $16,012,000 | 11.32¢ |
| Industrial | 97 | 215.5 GWh | 41% | $14,448,000 | 6.71¢ |
Customers, sales and revenue count every service type the utility reported (bundled, energy-only and delivery-only). The price column uses bundled service alone, because part-bill revenue would understate it. Sources of energy: 546.9 GWh in total, of which 0% was its own net generation and 546.9 GWh was bought wholesale; summer peak demand 118 MW.
By state
| State | Residential customers | ¢ per kWh | State average ¢ | Monthly bill | SAIDI, all events |
|---|---|---|---|---|---|
| Illinois | 9,339 | 14.97¢ | 15.87¢ | $111.64 | 17.6 |
| Wisconsin | 7,310 | 14.47¢ | 17.18¢ | $138.00 | 87.8 |
Reliability
Minutes of sustained interruption per customer in 2024, as the utility reported them under IEEE 1366 standard. SAIFI: 0.47 interruptions per customer with major event days, 0.36 without; CAIDI 100.6 minutes per interruption. EIA's Illinois total across all reporting utilities was 156.9 minutes with major event days and 59.4 without. Major event days are storms and similar events that a utility's chosen method sets apart; methods differ, so treat comparisons as approximate. What SAIDI and SAIFI mean.
| Year | SAIDI, all events | SAIDI, no major events | SAIFI, all events | SAIFI, no major events | Method |
|---|---|---|---|---|---|
| 2025 early release | 32.7 | 24.2 | 0.45 | 0.35 | IEEE 1366 |
| 2024 | 47.0 | 24.9 | 0.47 | 0.36 | IEEE 1366 |
| 2023 | 38.0 | 19.6 | 0.38 | 0.21 | IEEE 1366 |
| 2022 | 12.8 | — | 0.44 | — | IEEE 1366 |
| 2021 | 38.2 | — | 0.41 | — | IEEE 1366 |
| 2020 | 85.1 | — | 0.59 | — | IEEE 1366 |
Counties in its service territory
- Boone County IL
- McHenry County IL
- Stephenson County IL
- Winnebago County IL
- Dane County WI
- Green County WI
- Rock County WI
- Walworth County WI
Counties the utility listed on Form EIA-861 for 2024. Listing a county does not mean the utility serves all of it.
Other utilities in Illinois
| Utility | Ownership | Residential customers | ¢ per kWh | Monthly bill | SAIDI, all events | SAIDI, no major events |
|---|---|---|---|---|---|---|
| Tri-County Electric Coop, Inc (IL) | Cooperative | 16,197 | 16.04¢ | $189.61 | 372.0 | 63.7 |
| Jo-Carroll Energy, Inc | Cooperative | 17,227 | 19.79¢ | $140.17 | 66.6 | 48.9 |
| Norris Electric Coop | Cooperative | 18,074 | 15.08¢ | $170.15 | — | — |
| Egyptian Electric Coop Assn | Cooperative | 13,707 | 15.53¢ | $175.20 | 127.1 | — |
| Southeastern IL Elec Coop, Inc | Cooperative | 22,731 | 14.47¢ | $165.82 | 602.7 | 137.7 |
| Wayne-White Counties Elec Coop | Cooperative | 11,957 | 16.58¢ | $173.96 | — | — |
| Southwestern Electric Coop Inc | Cooperative | 24,822 | 13.68¢ | $153.82 | 304.8 | 263.0 |
| Eastern Illinois Elec Coop | Cooperative | 11,115 | 17.10¢ | $211.56 | 268.0 | 194.4 |
All Illinois utilities · Electric cooperatives nationwide
Questions and answers
How much does electricity cost from Rock Energy Cooperative?
Residential customers paid an average of 14.72¢ per kilowatthour in 2024. EIA derives this by dividing residential revenue by residential sales; it is an average across all rate schedules and charges, not a tariff rate.
How does that compare with Illinois?
The Illinois average residential price in 2024 was 15.87¢ and the US average 16.48¢; Rock Energy Cooperative was 7.2% below the state figure. Among 24 utility filings with a bundled residential price in Illinois, it had the 15th highest.
What is the average Rock Energy Cooperative bill?
$123.21 a month in 2024, on average residential use of 837 kWh a month (annual revenue and sales divided by customers and by twelve). The Illinois average was $109.99 on 693 kWh.
How reliable is Rock Energy Cooperative service?
It reported 47.0 minutes of interruption per customer (SAIDI) including major event days and 24.9 minutes excluding them, with 0.47 interruptions per customer (SAIFI) in 2024. Utilities calculate these under differing methods, so comparisons are approximate.
Is the Rock Energy Cooperative price rising?
The average residential price was up 2.4% in 2024 compared with 2023 and up 10.3% compared with 2019. EIA's early, not fully edited release for 2025 shows 14.58¢.
Which counties does Rock Energy Cooperative serve?
Its Form EIA-861 service territory lists 8 counties: Boone County, IL, McHenry County, IL, Stephenson County, IL, Winnebago County, IL, Dane County, WI, Green County, WI, Rock County, WI and Walworth County, WI. A county can appear in several utilities' territories.
Provenance
Source: U.S. Energy Information Administration. Annual figures are from Form EIA-861 (sales to ultimate customers, reliability, operational data and service territory files), final release for 2024, respondent "Rock Energy Cooperative", utility number 16196; the 2025 row is from EIA's early release. State and US averages are from the Form EIA-861M sales and revenue workbook, published through July 2026. All are US government works in the public domain. Page built 1 Oct 2026. Errors in processing are corrected at the next build; see corrections. For tariffs and rate schedules, consult the utility or the state utility commission.