The Biggest Red Flags in Biochar CDR Projects (From a Buyer’s Lens)

The voluntary carbon market is under scrutiny and CDR buyers know it.

Voluntary carbon credit retirements fell roughly 6% year-on-year amid growing scrutiny over integrity. It is also estimated demand for durable carbon removal could reach 50 to 200 million tons annually by 2030, far exceeding today’s verified supply.

All these translate to the fact that buyers are getting more selective.

In this context, from a procurement perspective, here are the biggest red flags in biochar CDR projects: 

1. Overconfident Permanence Claims

   “1,000 year carbon storage” sounds compelling but durability depends on chemistry. Scientific assessments show biochar stability varies significantly depending on feedstock and pyrolysis conditions. High-temperature biochars (typically >500°C) tend to show lower H/C ratios and greater aromatic stability, while lower-temperature production may result in faster decay.
   
   

   BloombergNEF (2024) notes, durable CDR credits command premium pricing precisely because long-term stability is uncertain and must be conservatively modeled. Experienced buyers assume some uncertainty in long-term storage. That’s why durable CDR credits cost more, the price reflects both longevity and the risk around it.

   
   If permanence claims aren’t backed by disclosed methodology, carbon fractions, and decay modeling assumptions, that’s a red flag.
   
   

2. Weak Additionality Narratives

   Would this project happen anyway without carbon revenue? If a biochar facility is already profitable due to energy sales, tipping fees, biomass contracts, or subsidies, then carbon credits may simply boost margins rather than enable the activity. Buyers increasingly have started to scrutinise whether carbon finance is truly “out of the course of business” and decisive for investment. 

   
   After high-profile baseline investigations, the Financial Times reported that integrity concerns eroded confidence across voluntary markets. For buyers, unclear financial additionality isn’t just a technical issue , it’s reputational and balance-sheet risk.
   
   

3. Unproven Scaling Assumptions

   Biochar projects often assume long-term access to abundant, low-cost agricultural residues. But biomass is becoming a contested resource. IEA Bioenergy (2024) and recent BloombergNEF briefings note rising demand for residues across SAF, renewable fuels, bioenergy, and industrial heat markets. As mandates expand, competition intensifies. 

   
   For buyers, this raises hard questions: Will feedstock prices rise? Could diversion undermine additionality? If supply assumptions aren’t backed by long-term contracts and sensitivity analysis, that’s a red flag.
   
   

4. Revenue Stack Fragility

   Many biochar projects depend on multiple income streams like carbon credits, heat sales, tipping fees, and by-products. While that sounds diversified, it can also mask risk. Recent market analyses, including Sylvera’s, show buyers are increasingly wary of projects that rely too heavily on high carbon credit prices in a volatile voluntary market. Serious buyers now ask simple questions: If credit prices drop by 30 to 50%, does the project still work? Can it operate without premium pricing? If the answer is no, delivery risk increases. Today’s institutional buyers aren’t just buying climate impact, they’re backing financially resilient businesses.