A portability rule put 1,775 megawatts of gas turbines next to a Southaven neighborhood

A $7 million sound wall is the visible mitigation at Southaven, and Scientific American's reporter, in a driveway in the Colonial Hills neighborhood, describes it doing little: a constant drone like a plane taking off and never leaving, audible through the walls of nearby homes ^[3]. Set that spend against what the site exists to earn. Cleanview, an energy-data firm tracking the industry, estimates AI data centers can produce $10 million to $12 million a year per megawatt ^[12]. Applied to 1,775 megawatts, that is about $17.8 billion to $21.3 billion a year ^[19], or roughly $2.0 million to $2.4 million an hour, which makes the sound wall the equivalent of about three hours of output ^[20]. Two caveats, and they matter. Cleanview's figure is an industry estimate per megawatt of data center capacity, and turbine nameplate capacity is not the same thing as revenue-earning computing capacity, so treat the total as a ceiling rather than a line in anyone's accounts. The ratio would have to be wrong by three orders of magnitude before the conclusion about relative size moved. Capital is not the constraint either: the same reporting has SpaceX, which acquired xAI and folded it into SpaceXAI, raising $75 billion in an initial public offering, briefly pushing Elon Musk's estimated net worth above $1 trillion ^[13].

The test Mississippi applied asks what the machine can do rather than what leaves it. Portability, not emissions rate, is the qualifying property, and it buys up to a year of operation ^[7]. Adding units does not change the category, and the fleet grew to dozens of units ^[8].

What the reporting does not contain is a measurement. No decibel readings, no stack emissions rates, no ambient air monitoring, no health data for Colonial Hills or Whitehaven ^[22]. The site is screened by black privacy fabric on the fence, with metal stacks and shimmering exhaust visible above it ^[18], which is roughly the epistemic position everyone outside is in. The noise is documented the way a reporter can document noise, by hearing it indoors ^[3]. That is evidence of a kind, though not the kind a court can weigh against a numerical standard, and the case as filed asks whether the operation is an unpermitted power plant ^[8] rather than what any instrument recorded.

Colossus 2, where SpaceXAI trains Grok, is one of the densest concentrations of computing power in the country ^[4]. The grid could not deliver enough electricity on the company's timeline, so it generated onsite instead of waiting for a conventional plant or a utility upgrade ^[6]. Nothing in the reporting describes ratepayers funding transmission here ^[23]; what moved was the combustion, and it moved across a state line. The gas burns in Mississippi and the electricity crosses to Tennessee ^[5], so the jurisdiction that granted the exemption is not the jurisdiction hosting the machines. Data centers now use around 4 to 5 percent of US electricity, and the Electric Power Research Institute projects 9 to 17 percent by 2030 ^[10], two to nearly four times the current share ^[21].

The federal intervention shifted the terms of the dispute onto ground where air quality is not the question. The Pentagon's chief digital and artificial-intelligence officer told the court in a sworn declaration that Grok is one of only four proprietary frontier models currently capable of supporting national-security applications ^[15]; the department had already awarded xAI a contract worth up to $200 million, and Grok for Government launched the same day ^[16]. Costa Samaras of Carnegie Mellon gives the commercial logic: firms go as fast as possible because every day offline is potential revenue lost ^[11]. The next site built this way will be argued over the same two things, a permitting category and a capability declaration, unless a permit obliges someone to produce a number.