Microsoft and waste management solutions startup Vaulted Deep have announced a significant long-term offtake agreement. Vaulted Deep will deliver up to 4.9 million tonnes of durable carbon dioxide removal over 12 years by storing organic waste deep underground. This marks one of the largest carbon removal deals globally to date.
Vaulted Deep, which was spun out of the injection well-focused waste management company Advantek in 2023, collaborates with municipalities, industrial operators, and agricultural producers to manage organic waste that cannot be reused or safely applied to land. The company sequesters sludgy organic wastes, including biosolids, manure, agricultural and food waste, and paper sludge—materials that would otherwise be incinerated, landfilled, or spread on land, leading to CO2 emissions. Vaulted Deep converts the waste into a carbon-rich slurry and uses proprietary slurry injection technology to permanently store the carbon underground, offering over 10,000 years of permanence.
The new agreement with Microsoft, running through 2038, will enable Vaulted Deep to expand its operations to new sites across the U.S. The company is actively seeking new waste partners across various industries to address their challenging organic waste management needs.
Julia Reichelstein, co-founder and CEO of Vaulted Deep, stated, “As carbon removal moves beyond pilots and prototypes, there is growing demand for solutions that can scale safely and address real-world problems. Vaulted offers a dual solution: it meets urgent waste management needs and drives measurable climate and public health improvements. This agreement reflects a broader shift in how carbon removal is being deployed. It is no longer limited to emerging technologies but is increasingly delivered through large-scale existing infrastructure with novel applications.”
This agreement is the latest in a series of large-scale carbon credit deals by Microsoft, the largest corporate buyer of carbon removal credits globally. Recent agreements include several multi-million tonne deals, as part of Microsoft’s efforts to become carbon negative by 2030. According to carbon dioxide removals platform CDR.fyi, the new agreement brings Microsoft’s carbon removal purchases to over 30 million tonnes, significantly ahead of the Frontier buyers group, the second-largest purchaser at 1.4 million tonnes.
Brian Marrs, Senior Director of Energy and Carbon Removal at Microsoft, commented, “Vaulted Deep provides a differentiated, scalable approach to permanent carbon removal with low technology risk. Its work delivers immediate climate benefits while stimulating local economies and addresses long-standing environmental challenges that communities face every day. We support this solution as part of our broader effort to accelerate durable, high-integrity carbon removal.”