The Memphis Externality
In Southaven, Mississippi, forty-six natural gas turbines sit on flatbed trailers behind an unmarked perimeter fence, burning at full load to train xAI’s Grok-4 on roughly half a million Nvidia GPUs across the state line in Memphis. The state does not regulate them. The trailers technically make them “mobile” sources under federal air law. They have never moved. They are a power plant. The nearest elementary school is one mile away. ...