Behind-the-meter gas is the data center buildout's real cost: 318 Mt a year

Bloomberg News, working from BloombergNEF data, counted 99 proposed on-site gas plants for data centers that would emit roughly 318 million metric tons of carbon dioxide a year if run at industry-standard rates ^[1]. The US electric power industry emitted about 1,485 million tons last year, according to Energy Information Administration data, so one subsegment of data center infrastructure could lift power sector emissions by 20 percent, and by as much as a third if the plants run flat out ^[2].

The mechanism matters as much as the tonnage. These are behind-the-meter projects, which can be permitted and built without the approval of utilities or the independent system operators responsible for grid reliability ^[3]. That is the point: the buildout has already strained the grid, drawing reliability warnings and moratoriums on new approvals, and even approved facilities wait years to interconnect ^[4]. "There is immense, immense pressure on the whole sector to get power, and get it fast," said David Pomerantz of the Energy and Policy Institute, a utility watchdog that promotes renewables, adding that developers are "sort of agnostic if it is clean or dirty" ^[5].

The estimate rests on 126 gigawatts of planned on-site gas capacity, a utilization range of 60 percent to 100 percent, and the burn rate of a typical single-cycle generator ^[6]. At the 60 percent end that implies roughly 0.48 tons of CO2 per megawatt-hour ^[7], and running the same fleet around the clock would put the figure near 530 million tons, about 36 percent of last year's power sector total ^[8]. Single-cycle units are now among the most commonly planned, and they are dirtier than the combined-cycle plants developers actually want but cannot get because of a yearslong turbine backlog ^[9]. Supply constraints, not preference, are setting the emissions intensity.

Discount the pipeline. Bloomberg notes that the scramble to serve AI demand has produced phantom projects and long-shot pitches, and not all of these plants will be built ^[10]. The concentration is still striking: 22 states from Alaska to Georgia, with more than a third of the projects in Texas, where Governor Greg Abbott recently announced a pause in data center approvals ^[11]. Cleanview identified Amazon as the developer of an 8,000-acre site in Pecos County that will become among the largest single sources of carbon pollution in the US ^[12], and about 30 miles west Chevron is building Microsoft a gas plant for a 2,000-acre complex ^[13]. Those two sites alone could produce more than 10 gigawatts, enough to power New York City on a hot summer day ^[14], with combined emissions as high as 45 million tons of CO2 equivalent according to regulatory filings ^[15] - roughly 14 percent of the entire tracked total from two addresses ^[16], and slightly less than half the cumulative emissions of Washington state, where both companies are headquartered ^[17].

Both Amazon and Microsoft back clean energy projects and say they aim to zero out their emissions contribution, pledges made before the AI boom under pressure from employees and activists ^[18]. The pipeline also includes projects backed by OpenAI and Anthropic, self-styled AI data center specialists, and investor groups shopping for tenants ^[19].

Watch three things: how long the Texas pause holds and whether other states copy it, whether the turbine backlog clears enough to shift new builds to combined cycle, and how emissions from a Chevron-owned plant serving a Microsoft load get booked. The last one determines whether the disclosures stay intact while the carbon goes up anyway.