The AI boom has triggered a race to secure power for the energy-hungry data centers used to train and operate AI models. While many tech and data center companies are investing in renewable energy and seeking low-carbon sources such as hydro and nuclear power, the need for speedy access to electricity is driving growth in another energy source: mobile generators and turbines powered by fossil fuels.
Elon Musk's xAI supercomputing facility in Memphis, Tennessee, is the prime example as local environmental groups claim the data center has quickly become a major source of pollution in a city already struggling with dirty air.
As Newsweek reported in August, Musk hired a fleet of mobile gas-powered units to provide electricity for the massive data center while xAI was awaiting a connection to the local power grid.
While many city officials cheered Musk's multimillion-dollar development, some Memphis citizen groups voiced concern about potential pollution and the lack of transparency or public input.
"There is no permitting process, no tracking, no documentation for what's happening," KeShaun Pearson told Newsweek at the time. Pearson, the president of a citizens' group called Memphis Community Against Pollution, explained that the xAI site is near a predominantly Black neighborhood that is already burdened by air pollution, and he worried about the emissions from the data center's mobile power units. "We know what community is going to have to deal with the fallout."
More than eight months later, xAI is just now in the process of securing air quality permits for the 35 gas-burning mobile power producers that ring the data center, raising concerns about planet-warming emissions and local air pollution.
The xAI media office did not respond to a request for comment.
Patrick Anderson, a senior attorney with the nonprofit Southern Environmental Law Center, has been working with local groups to try to assess emissions from the data center.
"There's been very little public information about what's going on out there," Anderson told Newsweek, so SELC did some legwork to gauge the pollution from the data center.
Through aerial photography and emissions information from the turbine manufacturers' specifications sheets, SELC was able to estimate the amount pollution such as nitrogen oxides, or NOx, which causes smog. Anderson said the group estimates that over the course of a year the xAI fleet of turbines would spew out somewhere between 1,000 and 2,000 tons of NOx.
"Either side of that range would rank them as probably the largest source of NOx in Memphis," Anderson said, adding that adding that the xAI facility could be a larger source of the pollutant than the nearby TVA power station or Valero oil refinery.
The xAI facility's size and the lack of public information make it unusual. But Anderson said it is also an example of a growing trend as more data centers add gas- or diesel-powered mobile generators and turbines.
"What is happening here could be what we see more of in the future," he said.
Anderson said SELC is also monitoring use of mobile turbines and generators in Virginia, which is home to the world's largest concentration of data centers.
Elsewhere, data center developers finding it hard to hook up quickly to the electric grid are making deals for power on wheels.
VoltaGrid, one of the companies supplying power equipment to the xAI facility in Memphis, announced a partnership in February to supply Vantage Data Centers with more than one gigawatt of power—enough electricity to power an average town.
"The sector faces a major hurdle in securing timely power at scale," Dana Adams, North America president for Vantage Data Centers, said in a statement. "Partnering with VoltaGrid is an ideal solution to deploy capacity in constrained power markets."
VoltaGrid said in a statement that it will emphasize sustainability and emissions controls.
Anderson said mobile power units can be equipped with pollution-control technology. But even then, he said, it is a missed opportunity to use clean energy.
"We'd rather see this with true renewables," he said. "If there are places in the country where you can't do it with renewables and you have to do it with fossil-fuel combustion, maybe that's not the right place to do it."
The mobile-power trend comes as the surging energy demand for data centers presents challenges for power suppliers and climate goals to decarbonize the electric grid.
A recent report from the International Energy Agency (IEA) projected that global energy demand from data centers will more than double in the coming five years.
In the U.S., the IEA said, electricity use by data centers will likely account for nearly half of the growth in electricity demand between now and 2030.
Late last month, Rhode Island Senator Sheldon Whitehouse and Pennsylvania Senator John Fetterman introduced legislation they titled the Clean Cloud Act to set emissions standards on the energy data centers use.
"We don't have to choose between leading the world on AI and leading the world on climate safety," Senator Whitehouse said in a statement. "Big technology and AI companies have all the money in the world to pay for developing new sources of clean energy, rather than overloading local grids and firing up fossil-fuel pollution."
The bill would assess a fee on large data centers for the power they use if it comes from highly polluting sources and use the revenues generated to assist ratepayers and invest in clean energy sources.
However, the legislation proposed by two Democratic senators is unlikely to advance in the Republican-controlled Congress, and the Trump administration is encouraging AI developers to embrace fossil-fuel energy sources such as gas and coal to power data centers.
Last week, the Environmental Protection Agency (EPA) issued a rule clarification allowing the use of some mobile gas and diesel power sources for data centers. In a statement accompanying the rule, EPA Administrator Lee Zeldin claimed that the Biden administration's focus on addressing climate change had hampered AI development.
"The Trump administration is taking action to rectify the previous administration's actions to weaken the reliability of the electricity grid and our ability to maintain our leadership on artificial intelligence," Zeldin said. "This is the first, and certainly not the last step, and I look forward to continue working with artificial intelligence and data center companies and utilities to resolve any outstanding challenges and make the U.S. the AI capital of the world."
The White House push for fossil-fueled AI could mean much more greenhouse gas emissions will be coming from the data center sector and host cities like Memphis might face more air quality problems.
Stephen Smith is executive director of the Southern Alliance for Clean Energy, another nonprofit group tracking the xAI data center's pollution and its permitting process. Smith told Newsweek that xAI's applications for connections to the local electrical grid indicate that the company has plans to greatly expand its computing power and energy needs.
"They are desperately trying to accelerate the interconnection with the grid," Smith said, even as the company seeks a permanent air quality permit from local authorities for some of the gas turbines already on the site.
Smith said that that as the Trump administration removes federal constraints on AI's energy use, Musk's fossil-fueled approach to rapidly scaling up an AI data center could become the model that other companies follow.
"I think in states like Tennessee and potentially other states that have more lax regulatory regimes, it may very well become the norm," he said.