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250 MW BESS operating in Maricopa, AZ — Salt River Project
250 MW
Nameplate Capacity
1
Generators
unit
Batteries
Technology
2024
Operating Since
Coordinates
33.4108, -112.3138
County
Maricopa, AZ
Nearby Plants
| Field | EIA | GEM | Wikidata |
|---|---|---|---|
| Operator | Sierra Estrella Energy Storage, LLC | — | — |
| Owner(s) | Sierra Estrella Energy Storage, LLC | — | — |
| Status | Operating | — | — |
Sierra Estrella Energy Storage is a 250 MW battery energy storage system (BESS) located in Maricopa County, Arizona. The plant began operating in 2024 and is owned and operated by Sierra Estrella Energy Storage, LLC. It is the 30th largest power plant in Arizona out of 47, and the 209th largest in the United States out of 514. The facility consists of a single generator utilizing battery technology with a total storage capacity of 1,000 MWh.
The plant's batteries have a duration of 4 hours and utilize lithium-ion (LIB) chemistry. Sierra Estrella Energy Storage operates within the Salt River Project balancing authority and the Western Electricity Coordinating Council (WECC) NERC region. The plant's primary fuel is listed as "MWH," indicating that it draws power from the grid to charge its batteries.
Generated from EIA, GEM, and public data sources
Grid Region
Mountain West
Market
WEIM Participant
NERC Region
WECC — Western Electricity Coordinating Council
Balancing Authority
−3.3K MWh
Net Charging
-42.2K MWh
Annual Net Energy
-1.9%
Capacity Factor
Positive values indicate net discharge (generation exceeds station load). Negative values indicate net charging. Pure battery storage plants are typically net negative due to round-trip efficiency losses.
2023
$1,361/kW
Est. Construction Cost
Total estimated cost: $340.3M
This plant's balancing authority participates in CAISO's Western Energy Imbalance Market (WEIM). Direct nodal pricing data is not yet available.
Last updated 2026-03-26
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ask pi about Sierra Estrella Energy StorageSalt River Project (SRP)
Grid Voltage
230.0 kV
Regulatory Status
NR — Non-Regulated
Entity Type
Independent Power Producer
Sector
IPP Non-CHP