Sun Streams 4

OperatingBESSSolarHybrid

Ranked #12 of 55 BESS plants in AZ#39 of 837 nationally

600 MW Batteries (300 MW) + Solar Photovoltaic (300 MW) operating in Maricopa, AZ — Arizona Public Service Company

EIAGEM

600 MW

Nameplate Capacity

Generators

units

Hybrid (2)

Technology

Batteries + Solar Photovoltaic

2025

Operating Since

Location

Coordinates

33.3715, -112.8353

County

Maricopa, AZ

Nearby Plants

Sun Pond
BESS170 MW · 1.7 km
Sun Streams, LLC
Solar160 MW · 2.4 km
Palo Verde
Nuclear4209.6 MW · 3.1 km

Ownership & Operator

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	—

Ownership Chain

GEM identifies the owner as Longroad Energy [100%]

This entity is not yet in the GEM ownership database — chain unavailable.

About

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

EIA Plant Profile Global Energy Monitor

Engineering & Generators

Grid Context

NERC Region

WECC

Balancing Authority

Arizona Public Service Company

Grid Voltage

525 kV

Regulatory Status

Entity Type

Independent Power Producer

Sector

IPP Non-CHP

Generation

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.

Financial DataBeta

Source: FERC Electric Quarterly ReportsHIGH

$25.0/MWh

PPA Price

Sun Streams Expansion, LLC

Contract Seller

Pricing & Market Data

This plant is outside organized wholesale electricity markets (ISOs/RTOs). Nodal pricing data is not available.

News & Articles (9)Beta