In a rush to get Colossus up and running, Musk’s AI company is relying on the same environmentally unfriendly, natural gas-powered turbines used to restore power in natural disasters.
By Cyrus Farivar, Forbes Staff
When Memphis, Tennessee’s grid couldn’t provide all the electricity needed to power xAI’s new Colossus data center, the Elon Musk led artificial intelligence company turned to a quick and dirty solution: mobile natural gas turbines.
These power plants on wheels are usually a last resort during emergencies, not a permanent solution; They were crucial in restoring power in Puerto Rico after Hurricane Maria left the island in ruins, for example. But data centers around the country have started to use them as a stopgap solution. There are at least four at the xAI site, possibly more, churning out not only electricity but pollutants like nitrous oxide and formaldehyde.
But shortly after the data center became operational, it became apparent to local journalists, along with environmental activists, that no public agency had actually authorized the use of mobile gas turbines that are powering it.
Patrick Anderson, a lawyer with the Southern Environmental Law Center, wrote the Shelby County Health Department in August 2024 “to verify that xAI is operating these turbines without the required air permit and bring an appropriate enforcement action for failing to obtain a permit.”
xAI did not respond to a request from Forbes for comment.
It wasn’t until January 2025 that xAI’s sister company, CTC Property LLC, finally submitted a formal permit application to the Shelby County Department of Health to not only backdate approval of the four mobile gas turbines already in operation, but to add 11 more. That would give the site 150 MW of power – on top of the 150 MW that the local grid is already providing it. All told, that’s enough electricity to power nearly 100,000 homes. (This document was first obtained and reported on in January by The Commercial Appeal, a newspaper in Memphis.)
While mobile turbines are cheap and easy to deploy compared to conventional natural gas-based stationary power plants, which can take years to build, they are considerably less energy efficient – sometimes by as much as 50%. They’re also much dirtier, emitting significantly more pollutants, primarily nitrous oxide and formaldehyde, per unit of energy generated.
“It’s very much a quick and dirty approach that’s very wasteful, financially and environmentally,” Daniel Cohan, a professor of civil and environmental engineering at Rice University, told Forbes.
“It’s far more expensive to run your own gas generator than it is to buy electricity off the grid.”
But for AI companies in the growth-at-any-cost phase of a transformative industry, mobile gas turbines are an easy stopgap for delivering the additional energy their proliferating new data centers require at a time when energy firms and stationary gas turbine manufacturers are backlogged to the point of near crisis. Tech firms don’t even need to buy them. Companies like Solaris Energy Infrastructure and APR Energy rent them out for years on end — and they’re cashing in on exploding demand.
“Anybody that has any assets is lucky to have them right now,” APR Energy CEO Chuck Ferry told Forbes. Those that don’t are scrambling to build more. In January, Scott Strazik, the CEO of GE Vernova, the world’s largest turbine maker (market capitalization: $88 billion) said in an earnings call that the company plans to build “70 to 80” large scale stationary gas turbines in 2026 — almost double the number it will produce this year.
As easy as they might be to get up and running, in large enough numbers, mobile gas turbines are subject to stringent emissions standards, particularly in areas that are already environmentally-stressed, like the area in which xAI’s data center is nestled. Despite this, the Shelby County Health Department told Forbes in a statement that “there is no set timeline for approval” of the mobile turbines at the xAI site.
According to its application, xAI sister company CTC Property claims that its proposed 15 mobile gas turbines would emit 9.79, or just under 10 tons of formaldehyde per year – a critical limit. Once any site crosses 10 tons per year, the EPA designates it as a “major source” of pollution under the Clean Air Act, triggering more regulation and monitoring, in part because formaldehyde is known to cause cancer. (Currently CTC’s application states the site is a “minor source.”)
“This is a new scale of energy demand that is hard to compare with anything else we’ve really seen – it’s kind of unprecedented,” Anderson, the lawyer, told Forbes.
Indeed, xAI is building out a second site in Memphis’ Whitehaven neighborhood where it recently purchased a $72.9 million lot. But is xAI also using mobile gas turbines here? It seems likely.
Right around the same time, APR Energy announced that it had deployed four new mobile gas turbines. It did not say where or for whom. But in an interview with Forbes, CEO Chuck Ferry did reveal a location: Memphis.
Asked if its new Memphis mobile gas turbine array was located in Whitehaven or contracted to xAI, he declined to say, telling Forbes the unnamed client had asked the company to keep it quiet. He refused to answer follow-up questions.
Joan Carr, a spokesperson at the Shelby County Health Department, told Forbes no permit applications have been submitted for the Whitehaven location.
More mobile gas turbines in Whitehaven will only make a rough environmental situation in south Memphis worse. The area hosts a former medical equipment sterilization company that the Environmental Protection Agency concluded presents an “elevated cancer risk” due to decades of a different kind of industrial pollution. Just five miles away is a functional oil refinery that generates particulate matter, nitrogen oxides, sulfur dioxide and carbon monoxide.
And 12 miles to the east is a former military waste disposal site, which has been designated as a Superfund site, or one that needs longtime hazardous material cleanup. Should they be deployed, 15 more mobile generators pumping out nitrous oxide and formaldehyde will only make things worse.
xAI’s shrouded ask-for-permission-later approach is not normal — and disrespectful to the local community that’s already suffered from such environmental hazards, Anderson, the Southern Environmental Law Center attorney, told Forbes.
“That’s extremely unusual and extremely weird,” he said. “I’ve been working in this field for eight years and I’ve never heard of this once, much less twice…It’s a pure disdain and disregard for the people of Memphis.”
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