Elon Musk’s xAI to pull about half of its smog-belching turbines powering Colossus

Newly completed substation will help bear the load

Updated Elon Musk's xAI is removing about half of the temporary gas-turbine generators powering its Colossus AI datacenter over the next two months, according to the Memphis Chamber of Commerce, not due to environmental concerns, but because a new nearby substation now supplies the needed power.

Reportedly built in Tennessee in just 122 days, the AI supercluster initially featured 100,000 Nvidia Hopper GPUs. That number has since apparently swelled to 200,000.

The system's reliance on mobile gas turbines for power drew ire from residents and environmental groups, who raised alarms about their impact on air quality and community health.

The issue reached a flash point in April when aerial footage obtained by the Southern Environmental Law Center (SELC) revealed that the AI startup had deployed 35 generators instead of the 15 originally reported, raising concerns that the supercomputer may be among the largest contributor of smog-generating nitrogen oxides (NOx) in the Memphis area.

Community leaders dismissed the findings, telling journos that Musk's LLM maker xAI had assured them that only 15 of the generators were actually in use, with the remainder there for backup power in the event of a failure.

However, thermal imagery later released by the SELC appeared to show heat plumes from 33 of the 35 turbines, casting doubt on those assurances.

A Politico report, citing estimates from the center, projected the facility could emit between 1,200 and 2,000 tons of NOx a year, based on manufacturer specs and assumed operating conditions.

Estimates based on the EPA's CO-Benefits Risk Assessment tool (COBRA) suggest emissions at that level could result in health-related costs of up to $18 million for county residents and $160 million or more for all residents within the affected smog range.

Turbines like these usually require permits from regulatory agencies under the US Clean Air Act. However, the 35 turbines currently employed by xAI don't require permits so long as they are used on a "temporary" basis for fewer than 365 days, Shannon Lynn, an environmental consultant hired by Musk's AI startup, argued during a recent webinar hosted by the Memphis Chamber.

And because they don't require permits, it appears xAI is running them without the systems required to reduce harmful NOx emissions.

According to the Memphis Chamber, xAI will remove half of its NOx-spewing temporary turbines by summer. However, that's not because of backlash from the community or concern for public health. Rather, it doesn't need nearly so many of them now that Memphis Light Gas and Water (MLGW) has completed work on a substation capable of supplying 150 megawatts of grid power to the site.

With the nearby substation complete and an additional 150MW worth of Tesla batteries, which utilities use for large-scale electricity storage backup, the Memphis Chamber of Commerce says the generators used to power the first phase of the system are no longer necessary.

"The temporary natural gas turbines that were being used to power the Phase I GPUs prior to grid connection are now being demobilized and will be removed from the site over the next two months," it said in a statement.

But while xAI may be scaling back, it'll continue to rely on temporary turbines for "Phase II GPUs of xAI until a second substation, already in construction is completed and connected to the electric grid," the Chamber noted. Those remaining temporary turbines will be removed in the fall once this substation is complete.

Even after all that, xAI plans to employ 15 permanent turbines at the supercomputing center to supply backup power to the facility in the event of an outage. Specifically, xAI plans to deploy eight new turbines with selective catalytic reduction (SCR) systems to combat these emissions, and retrofit seven of the existing "temporary" turbines with the tech for permanent use.

According to Lynn, these turbines are being permitted under the Clean Air Act, and will bring the NOx pollution down from a rate of nine parts per million to two when they're operating.

The Register reached out to xAI for comment and had not heard back at the time of publication. ®

Updated to add on May 8

Amid speculation xAI may sneakily relocate its generators elsewhere in the area for other purposes, the Memphis Chamber of Commerce on Thursday told us the turbines xAI is demobilizing at its Colossus supercomputer in Shelby County are not going to show up at Musk's second datacenter site on Tulane Road located south of Memphis.

“The company continues to evaluate various power solutions for its Memphis facilities while working within all applicable regulatory frameworks,” the chamber said on behalf of xAI.