Steel Dynamics Sinton Mill — Sinton, Texas
Overview
TYPE3’s map data identifies Steel Dynamics (SDI) Sinton Mill as a steel facility in San Patricio County, with city precision, coordinates 28.0361, -97.5169, Operating status, a 2019 announced field, a 2024 operational field, and a 150 MW seed estimate. Its note cites a $1.9 billion greenfield mill and says SDI arranged 100 percent zero-emission power sourced from Comanche Peak. The 2024 operational field is stale relative to SDI’s own later statement that production started in the first quarter of 2022. Zero-emission supply claims are electricity-attribute or contract facts, not on-site generation at the mill and not a measured load.
SDI’s Sinton page lists the mill at 8534 Hwy 89, Sinton, TX 78387, and repeats the three-million-ton design. TCEQ’s March 27, 2026 statement of basis for permit O4324 names Steel Dynamics Southwest, LLC, confirms the Highway 89 location, and describes two single-shell DC induced EAFs. SDI’s 2025 Form 10-K says the Sinton division purchases electricity at current market prices. SDI’s 2025 CDP response says the primary Sinton supplier supplies nuclear electricity under a contractual arrangement documented with Emission-Free Energy Certificates; that is not a statement that the mill sits at Comanche Peak, which is in Glen Rose. Do not convert GEM’s separate 308 MW wind-farm claim into mill demand.
Keep Sinton separate from Nucor Jewett and from Comanche Peak. Do not treat 3.0 versus 3.4 million tons as interchangeable without their source definitions, and do not convert either figure into megawatts. Current electrical demand and demand-response quantity remain unverified.
Questions
Is the Sinton mill operating?
Yes. SDI’s current mill page describes the operating Southwest-Sinton Flat Roll Division, and TCEQ’s 2026 Title V basis treats it as an operating steel mill.
Does Comanche Peak power mean the mill generates 150 MW?
No. Reviewed SDI disclosures describe purchased electricity and nuclear energy-attribute certificates. Comanche Peak is a separate nuclear plant in Glen Rose.
Which tonnage figure should the page use?
Keep both labeled: SDI’s three-million-ton design and TCEQ’s about 3.4 million tons per year. Neither is electrical demand.
Sources
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