Sandow Lakes / Xebec Megasite

Xebec Holdings · former Alcoa Rockdale site · Milam and Lee counties

The aluminum smelter that closed over power prices now hosts a solar cell plant, two AI campuses, a bitcoin mine and a gas plant. Four industries on one 33,000-acre inherited platform.

  • Solar manufacturing
  • AI training
  • Bitcoin mining
  • Power generation
Schematic of the 33,000-acre Sandow Lakes site: the Phase 1 advanced manufacturing campus with T1 Energy, the old smelter core with Riot and Bitdeer, the Sandow Lakes Energy gas plant site, Stargate Milam, the lakes, rail and FM 1786 SCHEMATIC, NOT TO SCALE SANDOW LAKES, ~33,000 ACRES 15 LAKES FM 1786 UNION PACIFIC ALONG US 79 Advanced Manufacturing and Logistics Campus, "The Switch": 3,300 acres, 35 million sq ft targeted, first occupancy Q3 2026PHASE 1: 3,300 AC T1 Energy G2 Austin: 5 GW TOPCon solar cell plant on 100 leased acres with a purchase option; about $850M and up to 1,800 jobs; first cells from the 2.1 GW Phase 1 targeted for Q1 2027T1 ENERGY Riot Rockdale: Converted bitcoin site on the old 700 MW-era grid connection, leased for AI and HPC; AMD and Anthropic are named in coverageRIOT ROCKDALE Bitdeer: One of North America's largest bitcoin mines, inside the 1950s smelter buildingsBITDEER Sandow Lakes Energy: Planned 1,200 MW behind-the-meter gas plant on the old power plant footprintGAS PLANT Stargate Milam (Freebird): SB Energy builds and runs 1.2 GW for OpenAI on 595 acres; Phase 1 of four data halls targeted October 2026STARGATE MILAM MILAM AND LEE COUNTIES
Site
~33,000 acres
Bought
$240M, 2021
Grid today
~1.5 GW
Grid by 2028
~3.9 GW
Industries
4
Sector
Energy and industrial

Overview

A Dead Smelter Running Four Industries

Select an industry to find its tenants on the site plan.

Sandow Lakes is the former Alcoa aluminum smelter, coal plant and mine on FM 1786 south of US 79 in Milam and Lee counties, about 15 miles east of Samsung Taylor. Xebec Holdings of Dallas bought the 33,000 acres from Alcoa in November 2021 for $240M and is redeveloping them as a multi-tenant megasite that JLL calls the only one in Texas combining power, water, rail, natural gas, fiber and highway access at this scale.

Five operators in four industries now share the site: solar cell manufacturing, AI training, bitcoin mining and power generation. The smelter closed because US power prices made aluminum uneconomical; the same ground now makes solar cells and generates its own electricity.

Industry
Tenants on the Sandow Lakes site
TenantIndustryWhat it runs here
T1 Energy G2 AustinSolar manufacturing5 GW TOPCon solar cell plant on 100 leased acres with a purchase option; about $850M and up to 1,800 jobs; first cells from the 2.1 GW Phase 1 targeted for Q1 2027
Riot RockdaleAI trainingConverted bitcoin site on the old 700 MW-era grid connection, leased for AI and HPC; AMD and Anthropic are named in coverage
BitdeerBitcoin miningOne of North America's largest bitcoin mines, inside the 1950s smelter buildings
Sandow Lakes EnergyPower generationPlanned 1,200 MW behind-the-meter gas plant on the old power plant footprint
Stargate Milam (Freebird)AI trainingSB Energy builds and runs 1.2 GW for OpenAI on 595 acres; Phase 1 of four data halls targeted October 2026

Power

1.5 GW Today, 3.9 GW by 2028

About 1.5 GW connected to ERCOTERCOT-connected today1,500 MW About 3.9 GW by 2028Oncor scaling by 20283,900 MW Sandow Lakes Energy, behind the meterPlanned on-site gas1,200 MW

The site inherited Alcoa's 700 MW-era grid connection, 1950s water rights, rail, gas and the lakes built to cool the smelter and power plant. Oncor is scaling the connection toward 3.9 GW, and Sandow Lakes Energy plans a 1,200 MW behind-the-meter gas plant on the old power plant footprint.

History

From Alcoa to Xebec

  1. 1951Alcoa opens the Rockdale aluminum smelter, with coal power, lignite mining and cooling lakes
  2. 2017Industrial operations end; US power prices had made smelting uneconomical
  3. November 2021Xebec Holdings buys the complex from Alcoa for $240M
  4. 2023The Legislature creates Sandow Municipal Utility District No. 1, funding water, sewer and roads with tax-exempt bonds without annexation
  5. March 2025T1 Energy leases 100 acres for its G2 Austin solar cell plant
  6. October 2025SB Energy begins Stargate Milam Phase 1
  7. Q3 2026First occupancy at the Phase 1 campus
  8. Q1 2027T1 Energy targets first cells from G2 Austin Phase 1
  9. 2028Grid connection scaling toward 3.9 GW through Oncor

Phase 1, the Advanced Manufacturing and Logistics Campus known as The Switch, covers 3,300 acres with 35 million sq ft targeted. BentallGreenOak has committed $475M, and the utility district lets Xebec finance infrastructure without city annexation, an advantage over peer sites that depend on it.

In the supercluster

Just Outside the Metro, Inside the Corridor

Milam and Lee are not Austin MSA counties, but Sandow runs on the same Oncor transmission build and the same workforce as the US 79 Data Center Corridor, and Union Pacific runs past it. It is the corridor's eastern edge: with Samsung Taylor, Skybox in Hutto and Terafab at Gibbons Creek, part of the densest AI-industrial run of US 79. See Brownfield Inheritance for the pattern.

Record

Dataset Record

Sources
Xebec Holdings, JLL, tenant announcements, Texas Legislature and press coverage through October 2026; Stargate Milam figures from the Texas data centers dataset
Site plan
Schematic, not to scale
Last verified
Q4 2026