Senken and Carbonsate Sign 50,000-Tonne Deal, Europe's Largest Biomass Storage Offtake

Permanent carbon removal has a supply problem: the entire global market has delivered roughly 1.5 million tonnes to date, an amount so small that a single new agreement, 50,000 tonnes secured this week between Senken and Carbonsate, now accounts for around 4 percent of everything the sector has ever produced. The deal, covering the 2026 to 2028 vintages of Carbonsate's biomass storage project in Namibia, is described as the largest biomass storage offtake signed in Europe and the largest for any project on the African continent.

 

The Scarcity Problem Driving Multi-Year Contracts

 

Corporate net-zero commitments are increasingly converging on the same narrow pool of verified permanent removal supply, and Senken chief executive Adrian Wons frames that convergence as the defining tension likely to shape the market for the next decade. Regulatory pressure is compounding the squeeze: CSRD reporting obligations and the Science Based Targets initiative's Corporate Net-Zero Standard v2.0 are pushing residual emissions onto corporate finance agendas in a way that makes durable removal a near-term procurement need rather than a distant target. Locking in volumes years before delivery, as Senken has done here through 2028, has become the standard response to a market where demand consistently outpaces what's actually available to buy.

This marks Senken's third multi-year supply commitment of 2026, following an earlier aviation-sector offtake spanning direct air capture, industrial biochar and regenerative agriculture, a pattern suggesting the company is deliberately building exposure across several distinct removal technologies rather than concentrating its supply base in one method.

 

UPCOMING WEBINAR

Moving Sustainable Procurement Beyond Cost to Strategic Value Creation

Online, 09 September 2026 · Balancing cost, managing supplier risk and building long-term value

 

The Mechanics: Why Burying Wood Works as Climate Infrastructure

 

Carbonsate's approach exploits a straightforward physical fact: wood sealed in an engineered underground chamber can neither burn nor decompose, so the carbon it contains stays locked away for centuries rather than cycling back into the atmosphere. That simplicity is the technology's commercial advantage. Unlike direct air capture, which requires an energy-intensive process to extract CO2 from ambient air before it can even be stored, biomass burial starts with carbon already trapped in solid wood, skipping the capture step entirely and delivering permanence at what the companies describe as a fraction of DAC's cost.

The Namibian site adds an ecological rationale on top of the climate mechanics. Around Otjiwarongo, decades of encroacher bush spreading across former grassland have degraded biodiversity and reduced groundwater recharge. Clearing that bush restores the rangeland, but the timber removed in the process would normally be burned or left to rot, releasing its carbon regardless. Carbonsate instead buries it, turning a land-restoration by-product into a verified removal credit, with Namibia's arid climate providing near-ideal conditions for keeping the buried wood dry and stable over the long term.

 

RELATED EVENT

Reuters Sustainability Europe 2026

London, 20–21 October 2026 · 400+ sustainability, finance and procurement leaders on regulatory uncertainty and Scope 3 data

 

Why Verification Rigour Was a Precondition, Not an Afterthought

 

Carbonsate's project didn't reach this offtake without clearing a specific bar first: Senken's Sustainability Integrity Index, a 600-plus data-point review the company says fewer than 5 percent of carbon projects pass. That screening sits on top of the project's existing Puro.earth verification and continuous monitoring through Carbonsate's own MRV system, with Isometric certification currently under evaluation as a further layer. For a market still recovering credibility after years of scrutiny over overstated or unverifiable credits, that stacked verification approach is arguably as important to this deal's significance as the tonnage itself.

 

What Happens Next

 

Carbonsate, operating since early 2025, expects to issue roughly 10,000 credits in 2026, a fraction of the volumes both companies say the site could eventually support once it scales beyond 100,000 tonnes annually. Both parties have signalled intent to expand the agreement as that capacity comes online. Whether the project hits that scaling trajectory on schedule, and whether it can keep pace with a 50,000-tonne commitment running through 2028, will determine how much this single deal actually moves the needle on a global permanent removal supply that, for now, remains strikingly thin.