Data last collected:
PowerPlantFactsEvidence report · prepared 19 October 2026https://powerplantfacts.com/entity/145
EIA plant 145
Apache Junction · Maricopa · AZ
Horse Mesa
Operated by Salt River Project
Published location
Where is Horse Mesa?
This locator uses the coordinates in the approved source record. It shows geographic context, not a site boundary, safety zone or property-risk area.
33.590700, -111.344000
Open the interactive map ↗Map data © OpenStreetMap contributors
Capacity is not generation. Nameplate MW describes equipment; annual MWh describes recorded output. Proposed and retired units are not added to operating capacity.
Equipment mix
Operating capacity by technology
Grouped from this plant’s represented generator records. Use the AZ plant index for regional peers.
See the evidence
Electricity output across the year
Monthly net generation shows the seasonal shape of this plant's represented output. A negative value is retained when the source reports net consumption.
1291
2501
3-2,626
45,816
511,772
616,694
717,404
816,793
915,067
1011,464
114,975
12204
MWh net generation · 2024 final edition · EIA 923 represented operating rows. 12 of 12 supplied rows shown; 0 missing values omitted. Months with no reported numeric value are omitted, not treated as zero.
Read the chart as a table
| Record | MWh net generation |
|---|---|
| 1 | 291 |
| 2 | 501 |
| 3 | -2,626 |
| 4 | 5,816 |
| 5 | 11,772 |
| 6 | 16,694 |
| 7 | 17,404 |
| 8 | 16,793 |
| 9 | 15,067 |
| 10 | 11,464 |
| 11 | 4,975 |
| 12 | 204 |
2024 monthly net generation
| Month | Net generation |
|---|---|
| 1 | 291 MWh |
| 2 | 501 MWh |
| 3 | -2,626 MWh |
| 4 | 5,816 MWh |
| 5 | 11,772 MWh |
| 6 | 16,694 MWh |
| 7 | 17,404 MWh |
| 8 | 16,793 MWh |
| 9 | 15,067 MWh |
| 10 | 11,464 MWh |
| 11 | 4,975 MWh |
| 12 | 204 MWh |
Operating generators
| ID | Technology | Fuel | MW | Status |
|---|---|---|---|---|
| HM4 | Hydroelectric Pumped Storage | WAT | 99.8 | OP |
| HM3 | Conventional Hydroelectric | WAT | 11.7 | OP |
| HM1 | Conventional Hydroelectric | WAT | 9.9 | OP |
| HM2 | Conventional Hydroelectric | WAT | 9.9 | OP |
Continue exploring
Similar-capacity plants in the same state
Identity, technology and limitations
EIA plant ID
145
Sector
Electric Utility
Water source
Salt River
Data edition
2024-final
Use this record
Questions this evidence can answer
01What exactly is this record?
Use the name, place, date and identifiers above to confirm that you have the right Horse Mesa power plant: capacity and generation | PowerPlantFacts record.
02What does the evidence establish?
Read the reported values with their units, coverage dates and source notes. Keep observed facts separate from estimates or interpretation.
03What should I verify next?
Follow the primary-source links and check the limitations before using this evidence for a decision, comparison or citation.
A closer look at Horse Mesa
Variation in the published months
Across 11 numeric monthly generation entries, 7 has the highest recorded value (17,404 MWh) and 12 the lowest (204 MWh). Their difference is 17,200 MWh. Missing months have not been treated as zero.
Reading the MW column
In the 4 numeric rows displayed in this table, MW ranges from 9.9 (HM1, HM2) to 99.8 (HM4). The difference is 89.9 in the column's stated units. This summary covers the displayed rows and retains the table's period and scope.
Generator capacity in different operating conditions
| Generator ID | Technology | Nameplate MW | Summer MW | Winter MW | Minimum load MW |
|---|---|---|---|---|---|
| HM1 | Conventional Hydroelectric | 9.9 | 10.0 | 10.0 | 3.0 |
| HM2 | Conventional Hydroelectric | 9.9 | 10.0 | 10.0 | 3.0 |
| HM3 | Conventional Hydroelectric | 11.7 | 11.7 | 11.7 | 3.0 |
| HM4 | Hydroelectric Pumped Storage | 99.8 | 119.0 | 119.0 | 80.0 |
EIA-860 2024 final source. Ratings describe capacity, not actual generation or availability. Missing ratings are not zero.
Source: US Energy Information Administration Form EIA-860 2024 plant and operable-generator workbooks; archive 2024. US EIA-authored information is generally public domain; cite EIA, preserve third-party exceptions, changes and no-endorsement context. Source-specific derived data.