Vaulted Deep Secures $35 Million Debt Facility to Expand Carbon Removal Infrastructure
Vaulted Deep has secured a $35 million debt facility from Italian banking group Mediobanca to expand its network of organic waste disposal and carbon removal infrastructure across the United States.
The financing was arranged by CFP Energy and will support the development of new waste disposal sites as well as further investment in technology intended to accelerate site selection, permitting, and project development.
According to Vaulted Deep, the facility is backed by revenues from waste service agreements and contracted carbon removal purchases, including long-term offtake agreements involving buyers participating in Frontier, the carbon removal advance market commitment.
The company describes the transaction as the largest publicly disclosed US commercial debt deal in durable carbon removal secured by long-term purchase contracts. While that characterization is based on publicly available transactions and therefore may not capture private financing arrangements, the deal represents a notable development for an industry that has historically relied heavily on equity investment, corporate pre-purchases and public or philanthropic funding.
Organic Waste Becomes Durable Carbon Storage
Vaulted Deep was founded in 2023 and uses technology derived from industrial subsurface waste management to permanently store carbon contained in organic materials.
Its feedstocks can include biosolids, manure, food and agricultural waste, paper mill sludge, and other organic materials that may otherwise be landfilled, incinerated, spread on land, or allowed to decompose.
Plants capture atmospheric carbon dioxide through photosynthesis, leaving some of that carbon stored in biomass and organic residues. When those materials subsequently burn or decompose, much of the carbon can return to the atmosphere.
Vaulted Deep processes suitable organic waste into a slurry before injecting it into deep geological formations. The objective is to isolate the carbon underground for thousands of years rather than allowing it to re-enter the atmosphere.
Frontier classifies the approach as biomass carbon removal and storage. Its accounting methodology measures the carbon contained in the biomass and subtracts emissions associated with activities including transportation and energy use to determine net carbon removal. Frontier says the pathway could potentially provide storage lasting more than 10,000 years.
The business model differs from carbon removal approaches that depend almost entirely on the sale of carbon credits because Vaulted Deep can also generate revenue by providing waste management services.
Municipalities, agricultural operators and industrial companies can pay the company to manage organic materials that are difficult to reuse or safely dispose of, creating an additional revenue stream alongside carbon removal contracts. This combination was an important part of the financing structure supporting the Mediobanca facility.
Frontier Contracts Provide Long-Term Revenue Visibility
Frontier has been one of the most important buyers supporting Vaulted Deep's development.
In May 2024, Frontier announced $58.3 million in offtake agreements under which Vaulted Deep is expected to remove 152,480 metric tons of CO2 between 2024 and 2027.
The agreements followed an earlier purchase of 1,666 metric tons, which Frontier said had already been delivered and verified at the time the larger contracts were announced.
Frontier highlighted several potential advantages of Vaulted Deep's approach, including long-duration geological storage and the possibility of scaling through existing waste streams. However, it also identified risks, including the need to secure sufficient suitable waste material and persuade waste generators to adopt an alternative disposal pathway.
Those long-term contracts are becoming relevant beyond simply creating demand for carbon removal.
Carbon removal developers often need substantial capital before projects begin generating meaningful revenue. When developers have multi-year contracts with financially established corporate buyers, lenders may have greater visibility into future cash flows.
Vaulted Deep's new financing therefore offers an example of carbon removal offtakes beginning to perform a role similar to long-term purchase agreements in other infrastructure sectors.
Axios described the transaction as a significant financing milestone for carbon removal because conventional debt has remained relatively rare in the sector. The publication also noted that Vaulted Deep benefits from having a business model that is not entirely dependent on carbon removal revenue.
Microsoft Agreement Could Drive Much Larger Expansion
Vaulted Deep has also secured major carbon removal agreements outside its Frontier contracts.
In July 2025, the company announced a 12-year agreement with Microsoft covering up to 4.9 million metric tons of durable carbon dioxide removal through 2038.
The companies did not disclose the financial value of the contract.
Vaulted Deep said the agreement would support the expansion of its waste management infrastructure to additional locations across the United States. Microsoft has become one of the world's largest corporate buyers of carbon removal as it works toward its goal of becoming carbon negative.
The scale of the Microsoft contract is considerably larger than Vaulted Deep's earlier Frontier agreement and could provide a longer-term source of demand as the company develops additional facilities.
Google Agreement Adds Methane Measurement
Google announced a separate agreement with Vaulted Deep in September 2025 to purchase 50,000 metric tons of carbon removal for delivery by 2030.
The removals are expected to be certified through the carbon removal registry Isometric.
The partnership also includes research involving Google, Vaulted Deep and Isometric aimed at improving methods for measuring methane emissions that may be avoided when organic waste is stored underground rather than allowed to decompose through conventional waste treatment pathways.
Methane is particularly relevant to organic waste because decomposition under certain conditions can generate significant methane emissions. Google said the collaboration is intended to apply more rigorous measurement approaches to those avoided emissions while separately accounting for permanent CO2 removal.
The initiative highlights a broader challenge for carbon markets: distinguishing permanent carbon removal from emissions that are prevented or avoided and developing credible methodologies for quantifying each climate benefit.
XPRIZE Provided Another Source of Growth Capital
Vaulted Deep also received $8 million in 2025 after finishing as second runner-up in the four-year, $100 million XPRIZE Carbon Removal competition.
XPRIZE required finalists to demonstrate carbon removal at meaningful operating scale. Vaulted Deep reported delivering 9,986 net metric tons of carbon removal during its demonstration period.
The company finished behind grand prize winner Mati Carbon and first runner-up NetZero, while UNDO Carbon finished as third runner-up.
XPRIZE said each of the winning teams had removed more than 1,000 net metric tons of CO2 during the final year of the competition, providing evidence that their technologies had moved beyond laboratory-scale demonstrations.
Carbon Removal Moves Toward Infrastructure Finance
The $35 million Mediobanca facility is relatively small compared with financing routinely raised for mature energy and infrastructure projects, but its structure may be more important than its absolute size.
Early carbon removal companies have generally depended on venture capital, government support, prizes and corporate buyers willing to pay relatively high prices for initial volumes.
Scaling projects capable of removing millions of tons of CO2 will require substantially larger amounts of capital.
Debt can potentially reduce the cost of financing that expansion compared with relying exclusively on equity. However, lenders generally require greater certainty around revenues, project performance, and operating risk.
Long-term carbon removal agreements could help meet that requirement by providing contracted demand before infrastructure is constructed.
The model resembles structures already used in renewable energy, where long-term power purchase agreements can provide revenue certainty that supports financing for new generation assets.
Carbon removal introduces additional risks, including verification requirements, technology performance, geological suitability, feedstock availability, permitting, and the financial reliability of buyers.
Vaulted Deep's financing therefore represents an early test of whether carbon removal purchase agreements can develop from mechanisms primarily intended to stimulate demand into contracts capable of supporting conventional infrastructure finance.
If similar transactions become more common, the significance of corporate carbon removal commitments could extend beyond the credits themselves. They could increasingly influence developers' ability to secure financing, construct facilities, and move carbon removal technologies toward commercial scale.
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