Microsoft is spending $1.7 billion to buy human waste, here’s why
Microsoft plans to remove 4.9 million metric tons of carbon dioxide by burying bioslurry.
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In one of the most unconventional bets in the climate-tech space, Microsoft has signed a $1.7 billion deal to inject human waste deep underground. The 12-year agreement with Vaulted Deep, a U.S.-based startup, isn’t aimed at powering AI or building cloud infrastructure—it’s about neutralizing carbon emissions, one flush at a time.
Microsoft plans to remove 4.9 million metric tons of carbon dioxide by burying bioslurry—an organic mix of human sewage, manure, and food waste—roughly 5,000 feet beneath the Earth’s surface. The idea: prevent this organic matter from decomposing in open environments, where it would release methane, a greenhouse gas more than four times as damaging as CO₂.
“We’re solving a surface-level problem by locking it permanently beneath the ground,” said Vaulted Deep CEO Julia Reichelstein in an interview with Inc.
With the average cost of carbon removal pegged at $350 per ton, Microsoft’s move represents one of the biggest investments yet in biological carbon sequestration. The company is trying to offset emissions generated by its rapidly growing AI and data center operations, which saw a 23–30% increase in carbon footprint from 2020 to 2024.
In 2023 alone, Microsoft released 75.5 million metric tons of CO₂ equivalent, much of it from Scope 3 emissions—the kind that come not just from direct energy use, but from upstream supply chains, concrete, steel, and server manufacturing.
A Dirty Job With a Clean Goal Traditional biosolid disposal methods—like spreading it across farmland—contribute to water pollution and can introduce harmful substances like PFAS (forever chemicals) into the environment. Vaulted Deep’s underground injection method eliminates both greenhouse emissions and pollution risks in one stroke.
Chasing a Bold PromiseThis poop-to-carbon-storage deal aligns with Microsoft’s aggressive climate goals. The tech giant has promised to become carbon negative by 2030, and by 2050, it plans to remove all historical emissions since its founding in 1975.
The company has already purchased more than 83 million tons worth of carbon removal credits—with 59 million bought in just the last year. The Vaulted Deep deal is a key part of this portfolio—and perhaps the messiest.
