• Senken has signed a multi-year agreement for 50,000 tonnes of permanent carbon removal, Europe’s largest biomass storage deal to date.
• Carbonsate will deliver the removals from its Puro.earth-verified biomass geological storage project in Namibia between 2026 and 2028.
• The deal gives European corporate buyers access to long-term removal supply as demand for permanent carbon credits begins to outpace verified capacity.

Climate finance platform Senken has secured 50,000 tonnes of permanent carbon removal through a multi-year agreement with Berlin-based Carbonsate.

The contract is Europe’s largest biomass storage deal to date. Deliveries will run from 2026 through 2028 and are scheduled to begin this year.

Carbonsate will generate the removals through its biomass geological storage project near Otjiwarongo, Namibia. The project has been verified by Puro.earth and screened through Senken’s Sustainability Integrity Index, which assesses projects against more than 600 data points.

Credits secured through the agreement will be supplied to Senken’s corporate partners with near-term demand for permanent carbon dioxide removal.

Long-term contracts address tightening CDR supply

The agreement comes as companies pursuing net-zero targets compete for a limited pool of verified permanent carbon removal.

Senken CEO Adrian Wons said longer-term purchasing commitments could give buyers greater certainty while helping developers expand capacity.

“Demand for permanent carbon removal is already outrunning supply: corporate net-zero targets all point to the same small pool of verified capacity. That gap will define the market for the next decade. We committed for multiple years to secure access for European buyers to credible removal at prices they can plan with.”

The contract is the second-largest buyer commitment globally within the biomass geological storage category. It is also the largest commitment associated with a project operating in Africa.

Global cumulative deliveries of permanent carbon removal currently total about 1.5 million tonnes. Senken said the 50,000-tonne agreement is equivalent to roughly 4% of that volume.

The transaction highlights the growing role of offtake agreements in financing the expansion of carbon removal infrastructure. Developers often need revenue certainty before investing in additional sites and operational capacity.

Johanna Broell, Co-founder and CEO of Carbonsate, said long-term commitments provide the certainty needed to build capacity ahead of future demand.

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Biomass storage targets permanent removal at lower cost

Carbonsate’s approach uses biomass geological storage, sometimes called biomass burial. Waste wood is placed within engineered underground chambers designed to prevent decomposition or combustion.

By limiting the conditions that allow stored biomass to break down, the process keeps captured carbon from returning to the atmosphere for centuries.

The method does not require the energy-intensive capture systems used by some other permanent removal technologies. That can allow biomass storage projects to provide durable carbon removal at a lower cost than direct air capture.

In Namibia, Carbonsate is using biomass generated from clearing encroacher bush from savanna surrounding Otjiwarongo. The project combines land management with long-duration carbon storage.

For buyers, however, cost is only part of the equation. Carbon removal procurement increasingly requires scrutiny of durability, monitoring, verification and broader environmental impacts.

Senken’s screening of the project through its Sustainability Integrity Index reflects that shift toward more detailed due diligence as the voluntary carbon market develops.

Corporate buyers move earlier to secure removal capacity

The deal offers a view of how the permanent carbon removal market may evolve as corporate net-zero deadlines move closer.

Many companies expect to reduce most operational and value-chain emissions directly. Yet residual emissions are likely to remain in sectors where complete decarbonisation is technically or economically difficult. Permanent removals are expected to play a role in addressing those residual emissions.

That creates a procurement challenge. High-integrity removal capacity remains small compared with the potential volume of future corporate demand.

Multi-year offtake agreements can help address that imbalance by giving developers clearer revenue visibility and buyers earlier access to future supply.

For European companies, the Senken-Carbonsate transaction also expands access to removal capacity outside Europe while directing climate finance toward an African project.

As corporate carbon strategies become more focused on durable removals, access to verified supply could become an increasingly important element of net-zero planning. The 50,000-tonne agreement shows that some buyers are already moving beyond spot purchases and using longer-term contracts to secure that capacity ahead of wider demand.