Gila River Power Block 4
Natural gas power plant in Maricopa County, Arizona. 619 MW of nameplate capacity across 3 generators, operated by Salt River Project.
Also known as EIA plant 55306
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Key facts
- Capacity
- 619 MWNameplate
- Generators
- 3 operatingEIA-860M, August 2026
- Operating since
- May 2003First generator online
- Operator
- Salt River ProjectEIA operator ID 16572
- Grid
- SRPBalancing authority SRP
- Price nodes
- None linkedNo verified ISO node
- Location
- Maricopa County, AZ32.9750, −112.6944
- EIA plant ID
- 55306EIA plant page
Data as of EIA-860M August 2026 (published 2026-09-24). Capacity is nameplate, not live output.
How much power Gila River Power Block 4 produces
Free · EIA-923Net generation, 2025
2.67 TWh
2,671,230 MWh, final
Capacity factor, 2025
49.3%
2024: 53.5%
January to July 2026
929 GWh
Provisional
Range, 2016 to 2025
1.1–2.9
TWh a year. Low 2019, high 2024
| Year | Net generation, MWh | Capacity factor | Months reported |
|---|---|---|---|
| 2000 | Not reported | Not reported | 0 of 12 |
| 2001 | Not reported | Not reported | 0 of 12 |
| 2002 | Not reported | Not reported | 0 of 12 |
| 2003 | 2,154,515 | Not reported | 6 of 12 |
| 2004 | 4,288,084 | Not reported | 12 of 12 |
| 2005 | 4,546,967 | Not reported | 12 of 12 |
| 2006 | 5,559,314 | Not reported | 12 of 12 |
| 2007 | 7,251,234 | Not reported | 12 of 12 |
| 2008 | 7,583,324 | Not reported | 12 of 12 |
| 2009 | 6,386,134 | Not reported | 12 of 12 |
| 2010 | 5,884,547 | 27.1% | 12 of 12 |
| 2011 | 3,233,311 | 14.9% | 12 of 12 |
| 2012 | 3,929,342 | 18.1% | 12 of 12 |
| 2013 | 4,119,938 | Not reported | 12 of 12 |
| 2014 | 2,566,958 | Not reported | 12 of 12 |
| 2015 | 1,831,990 | 36.9% | 11 of 12 |
| 2016 | 2,841,224 | 52.3% | 12 of 12 |
| 2017 | 1,154,420 | 21.3% | 12 of 12 |
| 2018 | 2,450,933 | 45.2% | 12 of 12 |
| 2019 | 1,071,988 | 19.8% | 12 of 12 |
| 2020 | 2,486,618 | 45.7% | 12 of 12 |
| 2021 | 2,551,721 | 47.1% | 12 of 12 |
| 2022 | 2,641,295 | 48.7% | 12 of 12 |
| 2023 | 2,015,688 | 37.2% | 12 of 12 |
| 2024 | 2,906,973 | 53.5% | 12 of 12 |
| 2025 | 2,671,230 | 49.3% | 12 of 12 |
| 2026 (provisional, partial year) | 928,654 | 29.5% | 7 of 7 |
* 2026 covers January to July and is provisional. Capacity factor is net generation divided by nameplate capacity times the hours of each reported month.
Power prices and basis
Free accountNo verified ISO price node is linked to this plant, or its price history could not load.
Emissions
Free · EPA CAMPDCO₂, 2025
1.17M
US short tons. 2024: 1.27M
SO₂, 2025
6
US short tons
NOx, 2025
83
US short tons
CO₂ per MWh, calculated
0.44 t
About 874 lb per MWh
2 of 2 EPA units reported CO₂ in 2025 (4CTGA, 4CTGB), matched to EIA plant 55306 through the EPA–EIA crosswalk. The per-MWh rate is EPA CO₂ divided by EIA-923 net generation. The two reporting boundaries can differ.
Water use
Free · EIA-923 cooling, USGSWithdrawal, 2024
788
million gallons
Consumption, 2024
788
million gallons
Source
wells
Ground, Fresh. Induced-draft tower
Watershed stress
Severe · 1.000
USGS SUI, HUC12 Gila Bend Municipal Airport
12 of 12 cooling months report withdrawal. Groundwater user; SUI describes surface water and is context only. Blank volumes are unreported, not zero.
Generators
Free · EIA-860M| Generator | Technology | Nameplate MW | Online since |
|---|---|---|---|
| CTG7 | Natural Gas Fired Combined Cycle | 174.0 | May 2003 |
| CTG8 | Natural Gas Fired Combined Cycle | 174.0 | May 2003 |
| ST12 | Natural Gas Fired Combined Cycle | 271.0 | June 2003 |
Ownership and offtake
ProOwnership and offtake are part of Pro
Owners and their shares, parent companies, and power purchase agreements with their buyers. EIA-860M lists Salt River Project as the operator, which is not always the owner.
Modeled data
ProPro adds modeled values for this plant. Everything above stays free.
Generation potential vs reported
Monthly potential at seasonal net capability, next to EIA-923 output. Shows how much of the plant's capability was used.
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Questions about Gila River Power Block 4
How much power does Gila River Power Block 4 produce?
Gila River Power Block 4 reported 2,671,230 MWh (2.67 TWh) of net generation in 2025, a 49.3% capacity factor on 619 MW of nameplate capacity. From January to July 2026 it reported 929 GWh, which is provisional.
Where is Gila River Power Block 4?
Gila River Power Block 4 is in Maricopa County, Arizona, at 32.9750, −112.6944. It is in the Salt River Project balancing area (SRP).
Who operates Gila River Power Block 4?
EIA-860M for August 2026 lists Salt River Project as the operator (EIA operator ID 16572). The operator is not always the owner.
When did Gila River Power Block 4 start operating?
Its first generator began operating in May 2003, according to EIA-860M.
Sources
- EIA-860 2025 (final) and EIA-860M August 2026: plant, generators, capacity, operator and location
- EIA-923 monthly net generation, 2000 to July 2026 (2026 provisional)
- EPA CAMPD annual emissions through the EPA–EIA crosswalk, 1995 to 2025
- EIA-923 cooling water 2024 and the USGS surface water supply and use index, Water years 2010-2020 (Oct 2009 to Sep 2020), mean of monthly values
Page updated 2026-10-04 from the InfraMap data build. Methodology · Data sources · EIA plant page