DOJ Defends Musk's Unpermitted Gas Turbines, Saying Shutting Down Grok Threatens National Security

Elon Musk's SpaceX has quietly spent about $1 billion buying a US gas turbine company to keep its vast AI data centre powered, even as the US government now argues in court that shutting down the unpermitted turbines behind the project would threaten national security. The Department of Justice and the Pentagon have both warned judges that turning off the fossil-fuelled units supporting Musk's Grok AI system could undermine military operations, according to filings cited in SpaceX's own IPO prospectus.

Musk is building his public image on clean technology. As head of Tesla, he turned electric cars from a niche experiment into a global mass-market business. In 2016, Tesla absorbed SolarCity and began selling solar roofs that were supposed to help break dependence on fossil fuels.

SpaceX's own S‑1 prospectus doubles down on that rhetoric, declaring that the sun holds 'approximately 99.8% of the solar system's energy' and calling solar the only 'truly scalable solution' to the world's power constraints in the age of AI. Yet when it came to powering SpaceX's new Colossus II data centre on the Tennessee–Mississippi border, the company reached for natural gas.

Elon Musk, Solar Evangelist, Turns To Gas Turbines

Colossus II is designed as a power-hungry hub for AI computing, including the Grok model that Musk has repeatedly advertised as a rival to OpenAI's systems. In the S‑1, SpaceX is blunt about how it plans to keep the servers running.

The company says it 'significantly' relies 'on natural gas and gas turbine technology to power our data centre operations,' and warns that its ability to grow 'depends in part' on access to gas at viable prices and a steady supply of turbines and associated kit.

That is where the billion‑dollar purchase of Jacksonville-based APR Energy comes in. Instead of acquiring a conventional, fixed gas power plant near Colossus II, SpaceX bought a specialist in small, trailer-mounted gas turbines and diesel generators. These mobile units can be trucked in and hooked up within days. In energy circles, that speed is precisely what makes them attractive. It also lets operators sidestep some of the months‑ or years‑long wrangling over siting and permits that typically dogs permanent power stations.

SpaceX has leaned heavily on that loophole. In Mississippi, it classifies APR's turbines as 'temporary mobile equipment units' and argues that they are therefore exempt from the state's air permitting regime. Environmental groups say that stretches the definition of 'temporary' beyond recognition.

DOJ Steps In To Shield Elon Musk's Turbines

In June, the Southern Environmental Law Centre and Earthjustice filed a lawsuit challenging SpaceX's approach. Their complaint, summarised in SpaceX's own filings, contends that the turbines are not really temporary because they are effectively parked in place at Colossus II and intended to remain there. They point out that SpaceX has already installed 59 units, with the fleet capable of emitting as much as 2,500 tonnes of nitrogen oxide a year.

Individually, each turbine's emissions are expected to sit below the Clean Air Act's 100‑ton-per-year threshold for unpermitted units. Taken together, the plaintiffs argue, the impact is far larger than the law ever intended to slip through on a technicality.

Ordinarily, this kind of fight might end with a settlement, a retrofit, or a gradual phase‑out. Instead, the US government has put its thumb on the scale. SpaceX's prospectus notes that the Departments of Justice and Defence have both urged courts not to shut the turbines down, arguing that doing so would harm national security because Grok is already used by the military. In other words, the AI Musk is selling to investors as a key growth engine has been recast in Washington as sensitive infrastructure.

For now, that buys him time. The S‑1 concludes that the mobile units are 'likely to remain at least for the remainder of the Trump Administration.' Nothing in those documents is independently confirmed beyond what SpaceX chose to disclose, so the legal and political calculations around Grok should still be taken with a grain of salt. What the company does admit, however, is that 'the outcome of these legal actions is uncertain.'

Investors reading between the lines can see the risk. A future administration that is less indulgent of fossil fuels, mega‑data centres or Musk personally could revisit both the permitting question and the national security argument, potentially forcing SpaceX into expensive changes in how it powers its AI infrastructure.

For SpaceX Investors, A Gap Between Rhetoric And Reality

The awkward tension here is hard to miss. Publicly, Musk continues to present solar as the key to feeding AI's massive appetite for electricity, and SpaceX touts a $26.5 trillion AI opportunity that it claims solar can ultimately unlock. Privately, in the near term at least, the company is doubling down on gas.

SpaceX even concedes that APR-style turbines are not the whole answer. The S‑1 acknowledges that Colossus II will still need extra capacity from the local grid on top of its self-generated power, and says the company plans to 'directly fund this capacity' through local utility partners. That means more capital tied up in energy infrastructure before investors ever see the AI returns they are being sold.

All of which raises a simple question that SpaceX itself never quite resolves. If solar is truly the 'only scalable solution' in the era of AI, why is the flagship AI data centre leaning so heavily on fossil fuels, and why is the first billion‑dollar power purchase not a solar build-out? Until there is a clearer answer than national security letters and mobile turbines on trailers, the gap between Musk's green brand and SpaceX's gas‑fired reality will remain uncomfortably wide.