600 MW Batteries (300 MW) + Solar Photovoltaic (300 MW) operating in Maricopa, AZ — Arizona Public Service Company
600 MW
Nameplate Capacity
2
Generators
units
Hybrid (2)
Technology
Batteries + Solar Photovoltaic
2025
Operating Since
Coordinates
33.3715, -112.8353
County
Maricopa, AZ
Nearby Plants
Owner data does not fully agree across sources.
EIA typically reports the operating utility, while GEM resolves to the financial owner or parent corporation. Both can be correct.
| Field | EIA | GEM | Wikidata |
|---|---|---|---|
| Operator | Sun Streams Expansion, LLC | Longroad Energy [100%] | — |
| Owner(s) | Sun Streams Expansion, LLC | Longroad Energy [100%] | — |
| Status | Operating | operating | — |
GEM identifies the owner as Longroad Energy [100%]
This entity is not yet in the GEM ownership database — chain unavailable.
Sun Streams 4 is a 600 MW hybrid power plant located in Maricopa County, Arizona. The plant, which combines solar photovoltaic generation with battery energy storage, began operating in 2025. It is owned and operated by Sun Streams Expansion, LLC. The facility consists of two generators utilizing both solar and battery technologies. The solar arrays use a fixed-tilt tracking system. Sun Streams 4 operates within the Arizona Public Service Company balancing authority and the Western Electricity Coordinating Council (WECC) NERC region.
The plant's latest annual generation was 647,185 MWh, resulting in a capacity factor of 14.7%. The battery energy storage system (BESS) has a duration of 4 hours. According to FERC data, the plant has a power purchase agreement (PPA) price of $25 per MWh. Sun Streams 4 is ranked as the 9th largest power plant out of 47 in Arizona, and 47th out of 514 nationally.
Generated from EIA, GEM, and public data sources
NERC Region
WECC
Balancing Authority
Arizona Public Service Company
Grid Voltage
525 kV
Regulatory Status
NR
Entity Type
Independent Power Producer
Sector
IPP Non-CHP
36.2K MWh
Net Discharge
647.2K MWh
Annual Net Energy
14.7%
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.
$25.0/MWh
PPA Price
Sun Streams Expansion, LLC
Contract Seller
This plant is outside organized wholesale electricity markets (ISOs/RTOs). Nodal pricing data is not available.
Last updated 2026-03-26
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