Hays Energy Project
VistraHays County
Hays Energy Facility is a four-block natural-gas combined-cycle station near San Marcos in Hays County, Texas. EIA's May 2026 inventory reports 989 MW of nameplate capacity, 931 MW of net summer capability, and 1,048 MW of net winter capability. ERCOT's September 2026 resource outlook separately lists the four HAYSEN resources at 988 MW installed and 844 MW of summer capability. Hays Energy, LLC is the registered owner and operator; Vistra identifies Hays in its Texas generation fleet.
Mapped infrastructure geometry associated with this asset.
Vistra generation subsidiary
ERCOT Resource Node to Unit Mapping
Four block-specific operating dates
Federal Operating Permit O2079
EIA plant 55144 · Inventory for Sep 2026.
| Generator | Technology | Status | Power (MW) | Energy (MWh) |
|---|---|---|---|---|
| U1 | Natural Gas Fired Combined Cycle | Operating | 241.7 | Unknown |
| U2 | Natural Gas Fired Combined Cycle | Operating | 241.7 | Unknown |
| U3 | Natural Gas Fired Combined Cycle | Operating | 252.8 | Unknown |
| U4 | Natural Gas Fired Combined Cycle | Operating | 252.8 | Unknown |
Similar plants ranked by technology, capacity, and distance.
Current generator records and technology attributes reported through EIA-860.
| Generator | Capacity | Technology | Operation | Status |
|---|---|---|---|---|
| U1 | 241.7 MW 234 MW summer | Natural Gas Fired Combined Cycle CS | May 2002 | Operating |
| U2 | 241.7 MW 232 MW summer | Natural Gas Fired Combined Cycle CS | Apr 2002 | Operating |
| U3 | 252.8 MW 231 MW summer | Natural Gas Fired Combined Cycle CS | Aug 2002 | Operating |
| U4 | 252.8 MW 234 MW summer | Natural Gas Fired Combined Cycle CS | Aug 2002 | Operating |
Monthly EIA generation history and recent market-resource behavior where linked telemetry is available.
Deterministic links to ERCOT market resources, price records, outage disclosures, queue records, and nearby infrastructure. Candidate joins remain labeled until corroborated.
Source-backed project transactions, agreements, land records, permits, and environmental disclosures. Portfolio and adjacent-project facts remain explicitly scoped.
Parties, market resources, and identifiers tied to this asset, with owner, operator, developer, EPC, compliance provider, and interconnecting entity roles kept separate.
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Project milestones and public references behind the asset profile.
EIA reports April 2002 for generator U2; ERCOT reports April 19, 2002 for HAYSEN_HAYSENG2.
Monthly generation is reported through EIA-923. Capacity factor uses the current EIA nameplate capacity and is shown only for complete calendar years.
4 ERCOT market resources · Gas turbine
Capacity factor is average output vs. this plant's observed peak.
Observed ERCOT settlement prices at HAYSEN1_2 over 365 days (2025-10-26 to 2026-10-25). This plant is also crosswalked to HAYSEN3_4; the point with the deepest price history is shown.
The TB2 figure is a price benchmark, not revenue: it values one perfect-foresight cycle per day between the 2 cheapest and 2 dearest hours of each day, gross of round-trip losses, and excludes ancillary services and any physical dispatch constraint. It describes what this node’s price shape was worth over the window — it is not this asset’s realized capture, and no dispatch is assumed or modelled.
Portfolio membership follows the latest EIA-860 reporting entity. It does not imply ultimate ownership.
EIA reports May 2002 for generator U1; ERCOT reports May 28, 2002 for HAYSEN_HAYSENG1.
EIA reports August 2002 for generators U3 and U4; ERCOT reports August 16 and August 15 respectively.
TCEQ renewed Federal Operating Permit and Acid Rain Permit O2079 through September 18, 2029.
ERCOT SCED disclosure is delayed, so plant performance windows end at the latest disclosed interval.
Answered from the published record above. Questions whose inputs this profile does not carry are omitted rather than estimated.
Hays Energy Project reports 989 MW natural gas of operating nameplate capacity. These technology ratings do not establish a common export limit. Source: EIA Sep 2026.
Hays Energy Project is a Natural Gas Fired Combined Cycle facility in Hays County, TX, participating in the ERCOT market.
Hays Energy Project is in Hays County, TX, inside the ERCOT balancing area.
Hays Energy Project is operated by Hays Energy, LLC according to the EIA generator inventory. Reporting membership does not by itself establish ultimate ownership.
Hays Energy Project reported 5,607.1 GWh over the twelve months to 2026-07. Figures are net generation as filed to EIA-923.
Hays Energy Project settles at HAYSEN1_2, interconnects at Hays Energy.
By capacity, Hays Energy Project ranks #98 of 540 operating plants of the same technology nationally. It ranks #14 of 68 in TX.
Plants within 25 km, nearest first, regardless of technology. Proximity is straight-line distance between mapped plant coordinates; it does not by itself establish a shared point of interconnection.
