Mililani South Solar Farm
Solar and battery storage project in Honolulu County, Hawaii. 78 MW of nameplate capacity across 2 generators, operated by Mililani I Solar LLC.
Also known as EIA plant 57242
This project groups Mililani South Solar Farm (EIA 57242). EIA reports them as separate plants.
Analyst: free account, 1 question a day.
Key facts
- Capacity
- 78 MWSolar 39.0 · Battery storage 39.0
- Generators
- 2 operatingEIA-860M, August 2026
- Operating since
- July 2022First generator online
- Operator
- Mililani I Solar LLCEIA operator ID 62893
- Grid
- Not reported
- Price nodes
- None linkedNo verified ISO node
- Location
- Honolulu County, HI21.4279, −158.0199
- EIA plant ID
- 57242EIA plant page
Data as of EIA-860M August 2026 (published 2026-09-24). Capacity is nameplate, not live output.
How much power Mililani South Solar Farm produces
Free · EIA-923Net generation, 2025
62.6 GWh
62,582 MWh, final
Capacity factor, 2025
20.7%
2024: 18.6%
January to July 2026
33.0 GWh
Provisional
Range, 2023 to 2025
62.6–68.2
GWh a year. Low 2025, high 2023
| Year | Net generation, MWh | Capacity factor | Months reported |
|---|---|---|---|
| 2000 | Not reported | Not reported | 0 of 12 |
| 2001 | Not reported | Not reported | 0 of 12 |
| 2002 | Not reported | Not reported | 0 of 12 |
| 2003 | Not reported | Not reported | 0 of 12 |
| 2004 | Not reported | Not reported | 0 of 12 |
| 2005 | Not reported | Not reported | 0 of 12 |
| 2006 | Not reported | Not reported | 0 of 12 |
| 2007 | Not reported | Not reported | 0 of 12 |
| 2008 | Not reported | Not reported | 0 of 12 |
| 2009 | Not reported | Not reported | 0 of 12 |
| 2010 | Not reported | Not reported | 0 of 12 |
| 2011 | Not reported | Not reported | 0 of 12 |
| 2012 | Not reported | Not reported | 0 of 12 |
| 2013 | Not reported | Not reported | 0 of 12 |
| 2014 | Not reported | Not reported | 0 of 12 |
| 2015 | Not reported | Not reported | 0 of 12 |
| 2016 | Not reported | Not reported | 0 of 12 |
| 2017 | Not reported | Not reported | 0 of 12 |
| 2018 | Not reported | Not reported | 0 of 12 |
| 2019 | Not reported | Not reported | 0 of 12 |
| 2020 | Not reported | Not reported | 0 of 12 |
| 2021 | Not reported | Not reported | 0 of 12 |
| 2022 | 36,806 | Not reported | 6 of 12 |
| 2023 | 68,226 | 20.1% | 12 of 12 |
| 2024 | 62,871 | 18.6% | 12 of 12 |
| 2025 | 62,582 | 20.7% | 12 of 12 |
| 2026 (provisional, partial year) | 33,017 | 18.5% | 7 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 accountNo verified ISO price node is linked to this plant, or its price history could not load.
Emissions
Free · EPA CAMPDNo EPA emissions units are linked to this plant.
Water use
Free · EIA-923 cooling, USGSNo 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| Generator | Technology | Nameplate MW | Online since |
|---|---|---|---|
| 1 | Solar Photovoltaic | 39.0 | July 2022 |
| 2 | Batteries | 39.0 | July 2022 |
Ownership and offtake
ProOwnership and offtake are part of Pro
Owners and their shares, parent companies, and power purchase agreements with their buyers. EIA-860M lists Mililani I Solar LLC as the operator, which is not always the owner.
Modeled data
ProPro adds modeled values for this plant. Everything above stays free.
Modeled curtailment
A range, not one number. The lower bound counts hours inside the production tax credit window; the upper bound is the no-credit case.
Expected vs reported generation
Monthly modeled expected output and physical potential next to EIA-923 reported output.
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Questions about Mililani South Solar Farm
How much power does Mililani South Solar Farm produce?
Mililani South Solar Farm reported 62,582 MWh (62.6 GWh) of net generation in 2025, a 20.7% capacity factor on 78 MW of nameplate capacity. From January to July 2026 it reported 33.0 GWh, which is provisional.
Where is Mililani South Solar Farm?
Mililani South Solar Farm is in Honolulu County, Hawaii, at 21.4279, −158.0199.
Who operates Mililani South Solar Farm?
EIA-860M for August 2026 lists Mililani I Solar LLC as the operator (EIA operator ID 62893). The operator is not always the owner.
Is Mililani South Solar Farm a solar or a battery storage plant?
Both. Solar capacity totals 39 MW and battery storage capacity totals 39 MW.
When did Mililani South Solar Farm start operating?
Its first generator began operating in July 2022, 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)
Page updated 2026-10-04 from the InfraMap data build. Methodology · Data sources · EIA plant page