Elon Musk’s Nvidia-powered Colossus supercomputer faces pollution allegations from under‐reported power generators
It needs so much more power than what the grid delivers.
The Colossus Supercomputer may be a colossal problem for the world's richest man.
Last July Elon Musk fired up the Colossus, a supercomputer that uses 100,000 Nvidia H100 GPUs on a single fabric. The site could draw only 7 MW at its launch, however, enough to power just 4% of its GPUs. To solve this, Musk deployed several massive mobile generators to deliver the site’s electrical demands.
This was supposed to be a temporary solution. At the same time, the Memphis facility awaited approval from the Tennessee Valley Authority (TVA) for at least 50 MW of supply and the completion of its 150 MW substation (which was supposed to be finished by 4Q24).
It’s already 2Q25, and Ars Technica reports that residents say the site is still using over 30 gas turbines, which “release harmful pollution that is tied to asthma, respiratory illnesses, and certain types of cancers.”
Currently, xAI has an ongoing application with the Memphis authorities for 15 turbines. But when the Southern Environmental Law Center (SELC) partnered with South Wings to photograph the site with thermal imaging cameras, they discovered over 30 hotspots, indicating the number of generators operating on the site.
These power sources operate without permits because a legal loophole allows generators to be used for 364 days without one. But with July 2025 coming quickly, xAI needs to have its applications approved. Otherwise, it risks slowing down its operations (or shutting down completely) without access to the electricity it needs for all its GPUs.
Thermal Imaging Shows At Least 35 Portable Methane Gas Turbines
We have to note that we only spot eight bright hotspots on the image shared by Ars Technica, which probably indicates an operating generator. The other hotspots are dimmer, which might suggest that they’re either idle or cooling down. So, it could be that these generators are being used in shifts to avoid excessive damage to a unit. Still, we cannot know how many are running concurrently until we see actual records.
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The Colossus Supercomputer has already been approved for 150 MW, but experts say it needs at least 155 MW to run all 100,000 GPUs concurrently. Furthermore, Musk is aggressively expanding his AI dreams, and the site has doubled its computing power to 200,000 GPUs in just 92 days.
If xAI is running all of these AI GPUs simultaneously, it would require at least 310 MW of power — this doesn’t include its miscellaneous power requirements, including electricity for lights, air conditioning, security systems, and more. With the tech billionaire reportedly raising more money to scale the site to a million GPUs, the Memphis site will likely require more power, at least 1.55 GW, to operate.
Residents are complaining because xAI uses multiple methane gas turbines to cover the shortfall in its electrical needs. They told Ars Technica that it “likely make[s] xAI the largest emitter of smog-forming” pollution, and that they’re now working with the SELC to petition the Shelby County Health Department to reject xAI’s gas generator applications. The latter’s Pollution Control Branch has even scheduled a public hearing so that people living within the area can weigh in on the issue.
What’s disconcerting is that flyers from an anonymous group called “Facts Over Fiction” have started appearing around the affected neighborhoods. These brochures claim that “xAI has low emissions” and that the turbines used on the site are “specially designed to protect the air we all breathe.” The people behind these notices cannot be traced directly back to xAI or Musk. Still, Justin Pearson, a Tennessee House of Representatives member, has urged local authorities to determine who was behind them.
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Jowi Morales is a tech enthusiast with years of experience working in the industry. He’s been writing with several tech publications since 2021, where he’s been interested in tech hardware and consumer electronics.
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jp7189 I did a little poking around and (aside from not running the datacenter at all), the generators and batteries are actually them being nice to the neighbors in my opinion. The workload of AI training has huge power fluctuations as the scheduled tasks spin up various clusters. Sometimes massive compute is used and sometimes there is low power idle time. It would absolutely wreck the power grid to deal with that, so xai installed tons of tesla energy batteries and charges the off the generators. The setup smooths out the fluctuations demanded of the power grid.Reply -
ezst036 This seems like the kind of thing that an Ars Technica journalist could selectively report.Reply
Yes, Elon has made himself a big public enemy, that still doesn't excuse selective reporting, which is actually editorializing in disguise as news.
The use of these generators is not unknown, but persons who tote the line will not be attacked under the guise of honest reporting. The Elon of 15 years ago got away with stuff like this and was held up by many of the same outlets now in outrage. -
SomeoneElse23 Reply
Not a public enemy, but an enemy of a certain group of haters who are incapable of seeing good in those they are told are the enemy.ezst036 said:This seems like the kind of thing that an Ars Technica journalist could selectively report.
Yes, Elon has made himself a big public enemy, that still doesn't excuse selective reporting, which is actually editorializing in disguise as news.
The use of these generators is not unknown, but persons who tote the line will not be attacked under the guise of honest reporting. The Elon of 15 years ago got away with stuff like this and was held up by many of the same outlets now in outrage. -
Alvar "Miles" Udell Do tell, what are the emissions products and numbers from these natural gas generators vs, say, a natural gas power plant, like the 1100MW natural gas power plant in Memphis?Reply -
YSCCC Somehow I've always been skeptical for the various companies burning away crazy amount of fuel for AI training only for the LLM to use chance calculations to look right in chat type use..Reply -
jlake3 Reply
Someone poked around, and according to GE the turbines used in the TVA's Allen Combined Cycle Plant about a mile down the road should achieve 63.6% efficiency. Portable units like the ones deployed by xAI typically operate around 35% efficient.Alvar Miles Udell said:Do tell, what are the emissions products and numbers from these natural gas generators vs, say, a natural gas power plant, like the 1100MW natural gas power plant in Memphis?
Didn’t see numbers on specific emissions products, but portable generators are subject to more lax standards on a per-unit basis than large installations. -
waltc3 So far, no laws are being violated, and this is of course just another thinly veiled attack on Musk by the sad people who thought he was wonderful until he revealed his personal political preferences. Used to be in the country that we all respected each other even though we may disagree politically--it was simply no big deal. That seems to have gone by the wayside, unfortunately.Reply -
Notton Let's see... hyperloop broke, cybertruck recalls, spacex exploding, twitter losing users...Reply
If it walks like a duck and quacks like a duck, then it's probably a duck. -
SpicyLlama Reply
It’s a combined-cycle steam/gas generation plant with only 3 gas fired units, not 15-30 raw gas turbines of questionable origin. Most of that 1100 MW is coming from steam turbines, not to mention an additional 1 MW of solar. Google is your friend.Alvar Miles Udell said:Do tell, what are the emissions products and numbers from these natural gas generators vs, say, a natural gas power plant, like the 1100MW natural gas power plant in Memphis? -
SpicyLlama Reply
Those who want respect, should give respect.waltc3 said:So far, no laws are being violated, and this is of course just another thinly veiled attack on Musk by the sad people who thought he was wonderful until he revealed his personal political preferences. Used to be in the country that we all respected each other even though we may disagree politically--it was simply no big deal. That seems to have gone by the wayside, unfortunately.