Harry D Mattison Gas Plant
Washington County, Arkansas · EIA plant ID 56328 · Operator: Southwestern Electric Power Co
Nameplate349MWSummer 294 MW
Generators4in service
Net generation220GWh12 mo to Dec 2025
Capacity factor9%gas/coal/oil units, summer MW
Heat rate12,073Btu/kWhfossil units, electric fuel, HHV
First online2007Runs as peaking
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), gas/coal/oil 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.
Annual data table
| Year | Net GWh | Capacity factor | Heat rate (Btu/kWh) |
|---|---|---|---|
| 2007 | 119.3 | 15.4% | 9,106 |
| 2008 | 72.8 | 2.8% | 12,298 |
| 2009 | 27.7 | 1.1% | 13,304 |
| 2010 | 95.6 | 3.7% | 14,250 |
| 2011 | 134.4 | 5.2% | 13,587 |
| 2012 | 101.8 | 3.9% | 13,267 |
| 2013 | 48.8 | 1.9% | 13,474 |
| 2014 | 28.6 | 1.1% | 12,646 |
| 2015 | 24.5 | 0.9% | 12,121 |
| 2016 | 117.3 | 4.5% | 12,132 |
| 2017 | 43.3 | 1.7% | 14,512 |
| 2018 | 49 | 1.9% | 11,895 |
| 2019 | 156 | 6.1% | 12,146 |
| 2020 | 48.2 | 1.9% | 13,502 |
| 2021 | 69.1 | 2.7% | 11,942 |
| 2022 | 207 | 8.0% | 12,187 |
| 2023 | 177.2 | 6.9% | 11,729 |
| 2024 | 278.7 | 10.8% | 11,301 |
| 2025 | 220.5 | 8.6% | 12,073 |
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 |
|---|---|---|---|---|---|---|---|---|
| 1 | Natural Gas Fired Combustion Turbine | GT | 86.5 | 75 | Dec 2007 | Operating (Standby / backup) | — | coming soon |
| 2 | Natural Gas Fired Combustion Turbine | GT | 86.5 | 75 | Dec 2007 | Operating (Standby / backup) | — | coming soon |
| 3 | Natural Gas Fired Combustion Turbine | GT | 88 | 72 | Jul 2007 | Operating (Standby / backup) | — | coming soon |
| 4 | Natural Gas Fired Combustion Turbine | GT | 88 | 72 | Jul 2007 | Operating (Standby / backup) | — | coming soon |
Owner / operator
Operator: Southwestern Electric Power Co. Ownership shares by in-service nameplate MW (EIA-860 Schedule 4; units not listed there are wholly owned by the operator).
| Southwestern Electric Power Co | 100.0% | 349 MW |
Nearby plants
Within 80 km.
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| UA Central Utility Plant | 6 MW | 16.6 km |
| Ozarks Natural Energy Community Solar | 1 MW | 18.3 km |
| Westside Wastewater Treatment Plant Hybrid | 11 MW | 20.6 km |
| Springdale School District | 3 MW | 21.2 km |