Millers Branch Solar
Haskell County, Texas · EIA plant ID 69101 · Operator: Southern Power Co
132 MW under construction (Solar Photovoltaic), first expected Dec 2026 · EIA-860M
Nameplate380MWSummer 380 MW
Generators2in service · 132 MW building
Net generation405GWh12 mo to Aug 2026
Capacity factor35%solar units, summer MW
Heat rate—thermal plants only
First online2026
The 12-month figures include preliminary EIA-923 months, which EIA revises. Final data runs through Dec 2025.
Monthly net generation
EIA-923, all units at the plant. Net of station use; storage can go negative.
FinalPreliminary
Capacity factor by year
Net MWh ÷ (summer MW × hours), solar units. Each year uses that year's EIA-860 ratings; the hollow dot is the latest 12 months.
Heat rate by year
Electric fuel MMBtu × 1000 ÷ net MWh (Btu/kWh, HHV), fossil units only; CT + CA counted as one combined-cycle block.
Heat rate applies to fuel-burning (thermal) units only.
Generators
EIA-860 (annual) with EIA-860M updates through Sep 2026. EIA-923 reports generation by plant, prime mover and fuel, not by unit, so unit-level output isn't shown.
| Gen ID | Technology | Prime mover | Nameplate MW | Summer MW | Online | Status | Planned retirement | OEM / model |
|---|---|---|---|---|---|---|---|---|
| MLB01 | Solar Photovoltaic | PV | 200 | 200 | Feb 2026 | Operating | — | coming soon |
| MLB02 | Solar Photovoltaic | PV | 180 | 180 | Aug 2026 | Operating | — | coming soon |
| MLB03 | Solar Photovoltaic | PV | 132 | 132 | planned Dec 2026 | Under construction | — | coming soon |
Owner / operator
Operator: Southern Power Co. Ownership shares by in-service nameplate MW (EIA-860 Schedule 4; units not listed there are wholly owned by the operator).
| Millers Branch Solar, LLC | 100.0% | 380 MW |
Nearby plants
Within 80 km.
| Inertia Wind Project | 301 MW | 3.9 km |
| Inertia Energy Storage | 13 MW | 5.2 km |
| Briggs Solar, LLC | — | 8.9 km |
| Quantum II Solar | — | 9.4 km |
| Quantum II BESS | — | 9.7 km |
| Throckmorton Wind | — | 10.3 km |