New data centers purpose-built for artificial intelligence are stoking a natural gas generation boom, forcing double-digit emissions increases at Amazon, Google and Microsoft. But Elon Musk’s frontier AI company, xAI, has the most potential to cause the new pollution, according to a new tracker from climate communications firm Climate Power.
The Data Center Air Pollution Tracker considers planned and operational data centers as listed by research firm Cleanview, evaluating their carbon-intensity using grid pollution metrics from the Environmental Protection Agency, the United Nations and two media organizations, The Financial Times and The Guardian.
The data is useful for corporations ramping up their AI and cloud services usage who want to keep tabs on how those decisions might impact emissions reduction commitments.
What the scores mean
The eight companies on Climate Power’s list were rated from 1 to 100, based on two factors: how many of their projects plan to use (or already use) behind-the-meter natural gas generators and the electricity mix of the local grids where their data centers are located. A grid that produces 200 pounds of carbon dioxide per megawatt-hour (CO2/MWh) was considered the cleanest; the least clean grids produce 1,000 lbs. CO2/MWh.
A score of 100 would indicate that the company uses only grid-connected power sources from the world’s cleanest electricity grids.
Amazon was closest to that elusive number, with a score of 68 and an average of 716 lbs. CO2/MWh. It has the lowest ratio of behind-the-meter natural gas projects of the eight companies.
It was followed by Microsoft with a 64 (757 lbs. CO2/MWh) and Google and Meta, which both earned a 61. Google’s lbs. CO2/MWh score was 857 versus 802 for Meta.
Anthropic and Open AI, the two most widely used frontier AI models, were close behind with a 59 and 56, respectively. Oracle received a 51, although its average carbon intensity was lower than Google’s or Meta’s.
xAI’s score was just 6. Its Colossus data center in Memphis uses smog-producing gas turbines that are largely unregulated.
The information is updated on a daily basis; these scores were current as of July 24.
Why it matters
The great AI data center buildout has inspired fierce community opposition not just because of their voracious electricity appetite — an estimated 194 gigawatts by 2035, or 20 percent of U.S. power production — but because the Trump administration is encouraging the use of new coal and natural gas to run them rather than clean generation sources.
That runs counter to Climate Power polling from June that suggests voters are far more likely to favor data centers that promise to use clean energy for their operations. Projects that used coal or natural gas had far less support among voters than those linked to solar or wind.
