# Plant X Unit 4

SPP asset profile · https://askthegrid.com/assets/facilities/plant-x-unit-4

Southwestern Public Service Company - Lamb County - SPP

Plant X is a natural-gas steam-electric power plant in the sandhills of Lamb County, Texas, south of the town of Earth, owned and operated by Southwestern Public Service Company (SPS), a subsidiary of Xcel Energy. Built in stages between 1952 and 1964 with four steam units totaling 434 MW, the plant today operates only its youngest unit: a 190.4 MW steam turbine that entered service in 1964. EIA-860 lists a scheduled retirement for that remaining unit in December 2027, which would end generation at the site. SPS has, however, told Texas and New Mexico regulators it wants to extend the operating life of its remaining older gas units, including Plant X's, as part of a multi-billion-dollar plan to meet fast-growing Permian Basin and data-center demand, so whether the 2027 date still stands is unsettled. It is also becoming a multi-technology hub: SPS built a 150 MW solar array on the old Unit 1 and 2 interconnections, and in May 2026 the New Mexico Public Regulation Commission approved a 150 MW/600 MWh battery storage project at Plant X, expected online in 2028.

## Metrics

- **Nameplate capacity:** 190.4 MW — Canonical EIA plant baseline.
- **Registry anchor:** Plant 3485 — plant-3485

## Facts

- **Technology:** Natural Gas Steam Turbine
- **Operator:** Southwestern Public Service Company
- **Planned retirement:** 2027-12 · confidence: high

## Related parties

- **Owner / operator:** Southwestern Public Service Company — Direct owner and operator of Plant X Unit 4 ([source](https://www.xcelenergy.com/company/rates_and_regulations/resource_plans/sps_2024_all-source_rfp))
- **Parent company:** Xcel Energy Inc. — Parent company of Southwestern Public Service Company ([source](https://corporate.my.xcelenergy.com/s/energy/service-areas/texas))

## Sources

- [interchange.puc.texas.gov](https://interchange.puc.texas.gov/Documents/55255_331_1427533.PDF) — interchange.puc.texas.gov · authoritative — Source retained for exact-record publication review.
- [interchange.puc.texas.gov](https://interchange.puc.texas.gov/Documents/55255_342_1444161.PDF) — interchange.puc.texas.gov · authoritative — Source retained for exact-record publication review.
- [interchange.puc.texas.gov](https://interchange.puc.texas.gov/Documents/55255_77_1338307.PDF) — interchange.puc.texas.gov · authoritative — Source retained for exact-record publication review.
- [interchange.puc.texas.gov](https://interchange.puc.texas.gov/Documents/58664_611_1597575.PDF) — interchange.puc.texas.gov · authoritative — Source retained for exact-record publication review.

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Canonical page: https://askthegrid.com/assets/facilities/plant-x-unit-4
Website: [Southwestern Public Service Company (Xcel Energy)](https://www.xcelenergy.com/company/rates_and_regulations/resource_plans/sps_2024_all-source_rfp)

Source: Ask the Grid — https://askthegrid.com/