ROLLING HILLS WIND FARM
OperatingWind power plant
- Capacity
- 444 MW
- Primary fuel
- Wind
- County
- Cass County
- Operator
- MIDAMERICAN ENERGY CO
- Status
- Operating
- Commissioned
- 2011
- EIA plant ID
- 57501
- Generators
- 1
- Technology
- Onshore Wind Turbine
- Net generation (2024)
- 1,666 GWh
- Capacity factor (2024, EIA nameplate)
- 39%
- Data vintage
- EIA-860 2024 final; EIA-923 2022-2024 final
- Coordinates
- 41.2191, -94.7311
ROLLING HILLS WIND FARM, a 444 MW Wind power plant in Cass County, Iowa. Operated by MIDAMERICAN ENERGY CO, commissioned 2011.
How ROLLING HILLS WIND FARM compares
With 444 MW of capacity, ROLLING HILLS WIND FARM ranks 8th among the 198 operating power plants Bywatts maps in Iowa and is the largest of the 63 operating Wind plants in the state. It accounts for about 8.7% of Iowa's operating Wind capacity and 2.9% of all operating capacity in the state. Nationally it is the 6th-largest of the 708 operating Wind plants in the database. Commissioned in 2011, it is newer than 83% of the 198 operating Iowa plants with a recorded commissioning year. Its operator, MIDAMERICAN ENERGY CO, runs 28 operating plants in Iowa totaling 8,028 MW. It shares Cass County with 3 other operating plants, including ATLANTIC and ANITA.
EIA-860 lists 1 generator at the site with 484 MW of nameplate capacity, all onshore wind turbine technology. Net generation was 1,666 GWh in 2024 (a 39% capacity factor), up 42% from 2022.
Grid neighborhood
The closest transmission line found within 10 miles is a 345 kV line owned by MIDAMERICAN ENERGY CO, about 2.7 miles away. Another 18 operating power plants totaling 792 MW sit within 25 miles; the largest is ECLIPSE WIND FARM (200 MW, Wind).
Computed by Bywatts from HIFLD power plant and transmission line records and EIA-860/923 survey data; distances are straight-line. Sources and methodology
Weather peril exposure
ROLLING HILLS WIND FARM is a 444 MW wind power plant in Cass County, IA, operated by MIDAMERICAN ENERGY CO, commissioned in 2011. Cass County carries high modeled catastrophe exposure in the FEMA National Risk Index, scoring 3.7 of 5 at the 67th national percentile. Tornado is the leading peril, rated Relatively Moderate by FEMA at the 98th percentile.
The Bywatts loss layer is calibrated to solar PV hardware, so it is not applied to a wind plant. The ratings below are the FEMA National Risk Index county hazard ratings for this location.
Cass County hazard ratings
| Peril | FEMA rating | National percentile | Peril score | Events per year |
|---|---|---|---|---|
| Tornado | Relatively Moderate | 98th | 4.9 of 5 | 0.48 |
| Heat wave | Relatively Low | 96th | 4.9 of 5 | 7.3 |
| Strong wind | Relatively Moderate | 87th | 4.5 of 5 | 4.9 |
| Ice storm | Relatively Low | 73rd | 3.9 of 5 | 0.76 |
| Winter weather | Relatively Low | 73rd | 3.9 of 5 | 12.5 |
| Hail | Relatively Moderate | 70th | 3.8 of 5 | 6.2 |
| Riverine flooding | Relatively Low | 56th | 3.2 of 5 | 1.3 |
| Lightning | Very Low | 52nd | 3.1 of 5 | 44.8 |
| Wildfire | Very Low | 50th | 3.0 of 5 | <0.01 |
| Earthquake | Very Low | 12th | 1.5 of 5 | <0.01 |
| Hurricane | Very Low | 10th | 1.4 of 5 | 0.01 |
Perils not assessed in Cass County
These perils carry no usable National Risk Index figure for this county, so they are excluded from the scoring rather than scored zero. A zero would claim the peril was assessed and found benign.
| Peril | Why it is not scored |
|---|---|
| Coastal flooding | FEMA rating is "Not Applicable" for this county |
Model hail, wind and flood exposure for Cass County in the weather risk calculator
Ratings are the FEMA National Risk Index county hazard ratings; the peril score is a Bywatts transform of the FEMA national percentile. Full data sources and the solar vulnerability methodology are in the weather risk calculator.
Modeled estimate for screening and negotiation. Built from FEMA National Risk Index county hazard data and a solar vulnerability layer documented above. Not a quote, a binder, or actuarial advice, and not a substitute for a carrier's own model. Hazard data: FEMA National Risk Index December 2025, synced 2026-07-24. Resolution is county level, not site level.