As US tech companies race to build data centers fueling the AI boom, they are increasingly putting up their own power plants—off the grid and running on gas—to get online faster. Analysis by the research firm Cleanview identified around 60 data centers planned for the coming years with a combined 97 gigawatts of “behind-the-meter” generation into the early 2030s—around the total installed capacity of Mexico. Even with very conservative assumptions, the plants would easily top 200 million tons of carbon dioxide emissions a year, equal to annual emissions of more than 46 million gasoline-powered cars. The latest addition—a 7.5 GW plant in Texas powering Amazon data centers—got air pollution permits in January, Amazon received construction permits last week, and satellite imagery confirmed clearing had begun at the site. Alongside greenhouse gases, gas plants emit fine particulate matter, nitrogen oxides, and hazardous air pollutants including mercury, formaldehyde and benzene. John Rogers of the Union of Concerned Scientists said powering data centers with behind-the-meter generation relying heavily on dirty gas or diesel turbines needlessly pumps hazardous pollutants into local communities’ air while worsening climate change. The practice began with Elon Musk’s decision to truck in mobile gas turbines to an xAI data center in Memphis in 2024. xAI still accounts for most of the two gigawatts online today, but nearly every hyperscaler is pursuing such projects, including Meta, Microsoft and Oracle. AI labs including OpenAI and Anthrop