12 MW Batteries (10 MW) + Solar Photovoltaic (2 MW) operating in Pima, AZ — Tucson Electric Power Company
12 MW
Nameplate Capacity
2
Generators
units
Hybrid (2)
Technology
Batteries + Solar Photovoltaic
2017
Operating Since
Coordinates
32.1033, -110.8220
County
Pima, AZ
Nearby Plants
| Field | EIA | GEM | Wikidata |
|---|---|---|---|
| Operator | Big Sky Wind, LLC | RWE Renewables Americas | — |
| Owner(s) | Big Sky Wind, LLC | — | — |
| Status | Operating | operating | — |
The Iron Horse Battery Storage Hybrid is a 12 MW hybrid power plant located in Pima County, Arizona. The plant, which began operating in 2017, is owned and operated by Big Sky Wind, LLC. It utilizes both battery storage and solar photovoltaic technologies. The battery energy storage system (BESS) has a storage capacity of 2.5 MWh and a duration of 0.25 hours, employing lithium-ion battery chemistry (LIB). The solar array uses a fixed-tilt tracking system. The plant's balancing authority is Tucson Electric Power Company, and it operates within the Western Electricity Coordinating Council (WECC) NERC region.
In its latest year of operation, the Iron Horse Battery Storage Hybrid generated 4,650 MWh, resulting in a capacity factor of 4.4%. The plant ranks 66th out of 68 power plants in Arizona and 723rd out of 1205 nationally. Financial data indicates a power purchase agreement (PPA) price of $65.2 per MWh, as reported to FERC.
Generated from EIA, GEM, and public data sources
NERC Region
WECC
Balancing Authority
Tucson Electric Power Company
Grid Voltage
13.8 kV
Regulatory Status
NR
Entity Type
Independent Power Producer
Sector
IPP Non-CHP
352 MWh
Net Discharge
4.7K MWh
Annual Net Energy
4.4%
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.
$65.2/MWh
PPA Price
Big Sky Wind, LLC
Contract Seller
Per-Unit Cost Trends
This plant is outside organized wholesale electricity markets (ISOs/RTOs). Nodal pricing data is not available.
Enlight begins build at 1.2GW US hybrid giant
Enlight Renewable Energy has reached final development milestones for the CO Bar complex in Arizona, clearing the way for full-scale...
Electricity and Energy Storage
Electricity storage on a large scale has become a major focus of attention as intermittent renewable energy has become more prevalent. Pumped storage …
Battery storage systems
Battery storage systems are a key element in the energy transition, since they can store excess renewable energy and make it available when it is needed...
Electricity and Energy Storage
The rapid increase in many parts of the world of generating capacity by intermittent renewable energy sources, notably wind and solar, has led to a strong...
Last updated 2026-03-26
View all 5 articles