Study Estimates Southaven Plant Emits 19 Times Permit Limit
A satellite-based study not yet peer reviewed estimates nitrogen oxide emissions from a Southaven power plant well above its permitted level.
Updated on Nov. 15, 2026 in Environmental
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Researchers using NASA's TEMPO satellite instrument estimate nitrogen oxide emissions from a Southaven, Mississippi power plant averaged about 870 kilograms per hour after February 2026, roughly 19 times the approximately 47 kilograms per hour its permit allows. The Mississippi Department of Environmental Quality Permit Board nonetheless voted November 10 to uphold the air permit for SpaceXAI and MZX Tech.
Why it matters
The estimates raise questions about whether emissions from the facility, which powers company data centers in Memphis, match what its permit allows. The study does not measure air quality at ground level and does not determine whether any standard was violated.
The figures come from a satellite-based emissions estimate rather than direct stack or ground monitoring, with an estimated uncertainty of about 165 kilograms per hour after February 2026. The study has not been peer reviewed and does not establish a permit violation.
The players
Mississippi Department of Environmental Quality
The state agency that issues and oversees air permits for industrial facilities in Mississippi, including the Southaven plant.
Andy Gipson
Mississippi's Agriculture Commissioner, who cast the lone vote against upholding the plant's air permit on the MDEQ Permit Board.
The details
Researchers used NASA's TEMPO instrument, which measures nitrogen dioxide in daylight hours from orbit over North America, and calibrated their estimates against continuous emission monitoring data from other U.S. power plants. The MDEQ approved a permit to construct 41 permanent turbines at the Stanton Road site on March 11, 2026, and the Permit Board voted November 10 to uphold the SpaceXAI/MZX Tech air permit, with Agriculture Commissioner Andy Gipson casting the lone vote against it.
Timeline
December 2025: Satellite first detected nitrogen oxide emissions from the plant, estimated at 530 kilograms per hour.
February 2026: Emissions are estimated to have exceeded the permitted level from this point onward.
March 11, 2026: MDEQ approved a permit to construct 41 permanent turbines.
August 23, 2026: The study was first posted on arXiv and last revised October 19, 2026.
November 10, 2026: The MDEQ Permit Board voted to uphold the air permit.
Environmental Monitoring
The study uses NASA's TEMPO satellite, which tracks nitrogen dioxide across North America, to estimate emissions from one facility, a use that extends the instrument beyond regional air-quality mapping. Its results remain unreviewed and depend on calibration against other power plants' continuous emissions data.
Residents concerned about air quality near the Southaven plant can review the facility's permit terms and ask MDEQ about ground-level monitoring plans. The study has not been peer reviewed, so its estimates should be weighed as preliminary.
The takeaway
Satellite estimates can flag possible emissions problems at individual facilities, but they require validation before they establish compliance. Readers should watch for peer-reviewed results and any ground-level monitoring that follows.
Further reading
For related coverage, see Environmental reporting on air permits and emissions in the Southaven area.
Source note: This article includes information reported by DeSoto County News.
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