BiocharBiochar is a carbon-rich material created from biomass decomposition in low-oxygen conditions. It has important applications in environmental remediation, soil improvement, agriculture, carbon sequestration, energy storage, and sustainable materials, promoting efficiency and reducing waste in various contexts while addressing climate change challenges. More is a valuable soil amendmentA soil amendment is any material added to the soil to enhance its physical or chemical properties, improving its suitability for plant growth. Biochar is considered a soil amendment as it can improve soil structure, water retention, nutrient availability, and microbial activity.   More that converts agricultural waste into a soil enhancer that can hold carbon, boost food security, increase soil biodiversity, and discourage deforestation. The process of biochar production creates a fine-grained, highly porous carbonaceous solid material that helps soils retain nutrients and water. Besides this, biochar also improves water quality and quantity by increasing soil retention of nutrients and agrochemicals for plant and crop use, keeping more nutrients in the soil rather than leachingLeaching is the process where nutrients are dissolved and carried away from the soil by water. This can lead to nutrient depletion and environmental pollution. Biochar can help reduce leaching by improving nutrient retention in the soil.   More into groundwater and causing pollution.

Often, Biochar carbon projects are framed as straightforward mechanisms, such as making biochar, applying it to soil, and storing carbon for the long term. But the reality is more complicated than assumed. Considering the diverse biomassBiomass is a complex biological organic or non-organic solid product derived from living or recently living organism and available naturally. Various types of wastes such as animal manure, waste paper, sludge and many industrial wastes are also treated as biomass because like natural biomass these More and farming systems across countries like India, early project design choices will determine whether carbon credit claims remain credible, especially around co-products. Co-products/By-products of biochar refer to the additional materials generated alongside biochar during the pyrolysisPyrolysis is a thermochemical process that converts waste biomass into bio-char, bio-oil, and pyro-gas. It offers significant advantages in waste valorization, turning low-value materials into economically valuable resources. Its versatility allows for tailored products based on operational conditions, presenting itself as a cost-effective and efficient More process, typically falling into three main categories: Solid (e.g., AshAsh is the non-combustible inorganic residue that remains after organic matter, like wood or biomass, is completely burned. It consists mainly of minerals and is different from biochar, which is produced through incomplete combustion.   Ash Ash is the residue that remains after the complete More, Fine-grained Char/Soot), Liquid (e.g., Wood Vinegar, Wood Tar, Bio-oil), and Gas (e.g., SyngasSyngas, or synthesis gas, is a fuel gas mixture consisting primarily of hydrogen and carbon monoxide. It is produced during gasification and can be used as a fuel source or as a feedstock for producing other chemicals and fuels.   More).

During my involvement in biochar system design, co-product analysis, and early-stage carbon project planning in India, I have repeatedly encountered similar blind spots. These blind spots rarely appear in proposals or methodologies, but they seem to emerge quickly during project implementation, focusing on concerns such as how co-products are treated, how permanence is understood, and how likely MRV is planned. The majority of biochar systems operating (especially in India) practice slow pyrolysis are multi-output systems. Often, carbon project designs treat these co-products as secondary/incidental and do not hold in practice, whereas they can potentially define the system boundary.

Each co-product reflects its decision about feedstockFeedstock refers to the raw organic material used to produce biochar. This can include a wide range of materials, such as wood chips, agricultural residues, and animal manure. More selection, operating temperature, and reactor configuration. If they are not explicitly defined and accounted for, uncertainty shifts to carbon mass balance, emissions attribution and MRV assumptions rather than being resolved. Among these co-products, wood vinegar is a useful example to address this broader issue, which is often discussed as a potential value stream yet remains highly variable and lacks standardization in practice. Its yield and composition vary significantly across feedstock types and operating conditions. Being treated as a uniform or negligible output creates system-level variability that later becomes difficult to justify during validation or verification periods.

Existing studies and practitioner observations suggest that wood vinegar, often assumed to be beneficial in carbon project narratives, can influence plant growth, control pests, and enhance soil biological activity under certain conditions. However, the outcomes are highly context-dependent, including concentration, application method, crop type, soil conditions, and production process. An inappropriate concentration of wood vinegar can cause phytotoxic effects rather than creating benefits. Currently, it should be treated as an enabling but uncertain component due to the lack of field-validated, standardized and transferable evidence, particularly in the context of CDR (carbon removal deployment).

In many biochar projects, permanence is reduced to a single principle: biochar is chemically stable, so carbon storage is guaranteed over longer periods. While the stability is well documented and supported in literature, its permanence at the project level is shaped by far more than just the material itself.

Permanence depends on factors in the upstream system, such as feedstock quality, pyrolysis temperature, residence timeResidence time refers to the duration that the biomass is heated during the pyrolysis process. The residence time can influence the properties of the biochar produced.   More, handling losses, and application practices. These factors interact with soil type, climate conditions and land management practices which differ regions-to-regions. The project design decisions made to optimize co-product recovery, such as liquid or energy outputs, can also indirectly influence char properties and its long-term carbon stability.

As a result, permanence should be understood as an outcome of the entire system, not just a fixed characteristic of biochar alone. Projects that rely entirely on material-level assumptions risk ignoring system-level vulnerabilities that may affect long-term carbon integrity.

Measurement, Reporting and Verification (MRV) refers to the processes used to quantify carbon removals, document how they are achieved, and independently verify that the reported emission outcomes are accurate and traceable. MRV is often treated as a downstream requirement which is to be addressed once production begins or once a carbon registry is selected. But as a practical approach, MRV feasibility must be determined much earlier in the planning for the system design and its operations. When co-products like wood vinegar are generated, the complexity of the MRV process increases. Decisions regarding how each output will be measured, document and attributed within the project boundary must be made during initial phase. Vague treatment of co-products can lead to gaps in carbon mass balance, inconsistencies in emissions accounting and weak traceability of outputs. On financial grounds, retrofitting MRV systems after implementation is costlier and riskier, particularly in multi-output systems commonly observed in biochar production.

There is growing interest in scaling biochar-based carbon removal projects due to their potential climate and soil co-benefits, but their scalable deployment depends not only on production capacity but also on credibility. The biochar carbon projects may appear linear/straightforward on paper, but they prove more difficult to address or defend under scrutiny. Based on the buyer’s approach, unresolved questions regarding allocation, permanence, and MRV can reduce confidence among investors and other stakeholders, resulting in slow adoption.

Co-products being addressed as an integral component of biochar systems does not weaken carbon credit claims; instead, they strengthen them. Having clear definitions, conservative accounting and transparent treatment of uncertainty improve long-term project resilience and trust.

Biochar typically sits at the intersection of climate mitigation, soil health, and circular biomass systems, with significant potential, but realizing this potential at a larger scale requires careful planning and design of the system. Therefore, co-products must be explicitly defined and accounted, their permanence should be evaluated as a system-level outcome and MRV must be embedded early.

In upcoming scenarios, the projects that acknowledge these realities are expected to create a greater impact and progress more cautiously, and will be positioned to deliver durable and credible carbon removal solutions, as they will address a prerequisite for implementing CDR projects in a much more responsible manner.

References

1. Lehmann, Johannes, and Stephen Joseph. “Biochar for environmental management: an introduction.” Biochar for environmental management. Routledge, 2015. 1-13. https://www.taylorfrancis.com/books/edit/10.4324/9780203762264/biochar-environmental-management-johannes-lehmann-stephen-joseph?refId=02369012-67d3-47d6-8c48-82ee8a9cc0ac&context=ubx
2. FAO biochar & soil health briefs chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/https://openknowledge.fao.org/server/api/core/bitstreams/1de07363-c84f-4e25-b15d-b8d857333c21/content
3. IPCC AR6 (biochar as a CDR pathway) chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/https://www.ipcc.ch/report/ar6/wg3/downloads/outreach/IPCC_AR6_WGIII_Factsheet_CDR.pdf
4. IEA Bioenergy Task 34 (Pyrolysis products) https://task34.ieabioenergy.com/pyrolysis-explained/
5. Shackley et al., 2011 (biochar systems) https://www.researchgate.net/publication/270821290_Shackley_et_al_Biochar_Tool_for_Climate_Change_Mitigation_and_Soil_Management
6. Agronomy (2024): Exploring the Potential of Wood Vinegar https://www.mdpi.com/2073-4395/14/1/114
7. International Journal of Agriculture Extension and Social Development (2025 review) https://www.extensionjournal.com/
8. Biochar Carbon Stability Test Method: An assessment of methods to determine biochar carbon stability. International Biochar Initiative. September 20, 2013. chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/https://biochar-international.org/wp-content/uploads/2018/04/IBI_Report_Biochar_Stability_Test_Method_Final.pdf
9. IPCC (2023). Sixth Assessment Report (AR6), Working Group III: Mitigation of Climate Change. Intergovernmental Panel on Climate Change. Chapter 7 & 12 https://www.ipcc.ch/report/sixth-assessment-report-working-group-3/
10. IPCC Guidelines for National GHG Inventories https://www.ipcc.ch/report/2019-refinement-to-the-2006-ipcc-guidelines-for-national-greenhouse-gas-inventories/
11. Verra VCS guidance on MRV https://verra.org/methodologies/methodology-for-digital-mrv-forest-carbon-crediting/
12. ICVCM Core Carbon Principles https://icvcm.org/core-carbon-principles/