HydroOperatingSRP

Stewart Mountain

Hydro power plant in Maricopa County, Arizona. 13 MW of nameplate capacity across 1 generator, operated by Salt River Project.

Also known as Stewart Mountain Power Plant · EIA plant 150

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Mormon FlatHorse MesaPediment BESS ISantanQueen Creek Solar FarmStewart Mountain20 km
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6 plants within 34 km, from EIA coordinates.

Key facts

Capacity
13 MWNameplate
Generators
1 operatingEIA-860M, August 2026
Operating since
March 1930First generator online
Operator
Salt River ProjectEIA operator ID 16572
Grid
SRPBalancing authority SRP
Price nodes
None linkedNo verified ISO node
Location
Maricopa County, AZ33.5661, −111.5360
EIA plant ID
150EIA plant page

Data as of EIA-860M August 2026 (published 2026-09-24). Capacity is nameplate, not live output.

How much power Stewart Mountain produces

Free · EIA-923

Net generation, 2025

36.6 GWh

36,588 MWh, final

Capacity factor, 2025

32.1%

2024: 40.0%

January to July 2026

Not reported

Provisional. 0 of 7 months reported

Range, 2015 to 2025

−0.2–45.7

GWh a year. Low 2017, high 2024

Annual net generation, GWhCapacity factor below each year
Annual net generation from EIA-923
YearNet generation, MWhCapacity factorMonths reported
200021,939Not reported12 of 12
200131,441Not reported12 of 12
200218,629Not reported12 of 12
20036,552Not reported12 of 12
200415,497Not reported12 of 12
200533,569Not reported12 of 12
200648,987Not reported12 of 12
200739,192Not reported12 of 12
200827,022Not reported12 of 12
200951,466Not reported12 of 12
201037,39132.8%12 of 12
201143,19337.9%12 of 12
201240,79935.7%12 of 12
201319,68917.3%12 of 12
201418,34116.1%12 of 12
201518,76616.5%12 of 12
201627,41924.0%12 of 12
2017−179-0.2%12 of 12
201825,73022.6%12 of 12
2019−164-0.1%12 of 12
202020,34017.8%12 of 12
202126,61223.4%12 of 12
202231,17427.4%12 of 12
202334,97830.7%12 of 12
202445,70840.0%12 of 12
202536,58832.1%12 of 12
2026 (provisional, partial year)Not reportedNot reported0 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 account

No verified ISO price node is linked to this plant, or its price history could not load.

Emissions

Free · EPA CAMPD

No EPA emissions units are linked to this plant.

Water use

Free · EIA-923 cooling, USGS

No EIA cooling-water record for this plant in 2024. Plants without steam cooling, such as wind, solar and batteries, do not report cooling water.

Generators

Free · EIA-860M
GeneratorTechnologyNameplate MWOnline since
SMConventional Hydroelectric13.0March 1930

Ownership and offtake

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Ownership 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

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Power plants near Stewart Mountain

More plants operated by Salt River Project

Questions about Stewart Mountain

How much power does Stewart Mountain produce?

Stewart Mountain reported 36,588 MWh (36.6 GWh) of net generation in 2025, a 32.1% capacity factor on 13 MW of nameplate capacity.

Where is Stewart Mountain?

Stewart Mountain is in Maricopa County, Arizona, at 33.5661, −111.5360. It is in the Salt River Project balancing area (SRP).

Who operates Stewart Mountain?

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 Stewart Mountain start operating?

Its first generator began operating in March 1930, 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)
  • Plant names from OpenStreetMap, © OpenStreetMap contributors (ODbL)

Page updated 2026-10-04 from the InfraMap data build. Methodology · Data sources · EIA plant page