# Hays Energy Project

ERCOT asset profile · https://askthegrid.com/assets/facilities/hays-energy-project

Vistra · Hays County · ERCOT

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.

## Profile

- **Market mapping:** Four ERCOT South-zone resources mapped to HAYSEN1_2 and HAYSEN3_4.
- **Capacity records:** EIA: 989 MW nameplate, 931 MW summer, 1,048 MW winter. ERCOT September 2026: 988 MW installed, 844 MW summer.
- **Environmental record:** TCEQ Regulated Entity RN100211689; Federal Operating Permit and Acid Rain Permit O2079, effective through September 18, 2029.

## Metrics

- **EIA net summer:** 931 MW — May 2026 · four operating blocks
- **EIA nameplate:** 989 MW — 1,048 MW net winter capability
- **ERCOT summer:** 844 MW — 988 MW installed · Sep 2026
- **12-month generation:** 5.65 TWh — May 2025–Apr 2026 · EIA Form 923
- **Capacity factor:** 69.27% — Current EIA net-summer denominator
- **Resource stack:** 4 resources — HAYSEN_HAYSENG1 · HAYSEN_HAYSENG2 · HAYSEN_HAYSENG3

## Facts

- **Owner / operator:** Hays Energy, LLC — Vistra generation subsidiary · confidence: high
- **Settlement points:** HAYSEN1_2 · HAYSEN3_4 — ERCOT Resource Node to Unit Mapping · confidence: high
- **Commercial operation:** Apr–Aug 2002 — Four block-specific operating dates · confidence: high
- **TCEQ entity:** RN100211689 — Federal Operating Permit O2079 · confidence: high

## Sources

- [EIA May 2026 generator inventory](https://www.eia.gov/electricity/data/eia860m/) — U.S. Energy Information Administration · regulatory — Four current generators, capacity, technology, operating dates, operator, and ERCOT assignment.
- [TCEQ Federal Operating Permit O2079](https://records.tceq.texas.gov/cs/idcplg?IdcService=TCEQ_EXTERNAL_SEARCH_GET_FILE&Rendition=Web&dID=8170531) — Texas Commission on Environmental Quality · regulatory — Exact facility identity, RN100211689, permit term, operator, and address.
- [TCEQ O2079 technical review](https://records.tceq.texas.gov/cs/idcplg?IdcService=TCEQ_EXTERNAL_SEARCH_GET_FILE&Rendition=Web&dID=8170532) — Texas Commission on Environmental Quality · regulatory — Four GT24 turbines, four HRSGs, four steam turbines, and NSR permit 40040 / PSDTX923.

---

Canonical page: https://askthegrid.com/assets/facilities/hays-energy-project
Website: [Vistra](https://vistracorp.com/)
Profile published: 2026-07-17T08:58:50.999Z
Source: Ask the Grid — https://askthegrid.com/