Puro.earth Launches Public Consultation for Biochar Methodology Update

3/04/2025

We are pleased to announce the launch of the public consultation for the update to the Puro Biochar methodology. The consultation also includes an update to the Biomass Sourcing Criteria, for alignment with the methodology. A Transition Plan is also released as part of the consultation, explaining how the adoption of the updated methodology will be managed by Puro.earth.

The proposed 2025 update intends to strengthen the integrity of biochar-based CDR by incorporating recent scientific advances relating to biochar persistence, as well as numerous clarifications and refinements derived from five years of practical experience in certifying biochar projects. The update also aligns the methodology with the latest Puro General Rules. Overall, the core principles that Puro defined for biochar certification in 2019 remain unchanged but have now been expanded and clarified to further support scaling of biochar.

For this update, we have collaborated with a diverse group of experts, held three workshops and interviewed other relevant stakeholders. We thank them for their invaluable contribution to our methodology development process.

Key Highlights:

Full alignment with Puro.earth General Rules 4.1 and ICVCM CCP
Increased durability from CORC100+ to CORC200+, representing biochar carbon removal over several centuries
Incorporated learnings and clarifications, regarding sound biochar systems, from biomass sourcing to biochar end-use

We welcome feedback from all stakeholders during this period. Your input is invaluable to our methodology development process, ensuring transparency and informed decision making.

Consultation Period:

April 3–24, 2025

Public Consultation Documents:

How to Participate:

1. Download the public consultation documents linked in the section above.

2. Submit your input using the feedback feedback form to contact@puro.earth by April 24th.

Download the feedback form

3. Join the webinar on April 16, 2025 at 11:00 a.m. EDT/5:00 p.m. CET to learn more about the public consultation.

Frequently Asked Questions:

1. What are the main changes in the updated methodology?

Overall, the core principles that Puro defined for biochar certification in 2019 remain unchanged but have now been expanded and clarified to further support scaling of biochar. More precisely, the core changes introduced are:

Updated biochar persistence equations and extended durability claims to several centuries.

Explicit definitions for Mobile and Stationary Production Facilities, and procedures for Capacity Expansion Audits.
Updated rules for biomass eligibility, aligned with the Puro Biomass Sourcing Criteria (traceability and sustainability), and rules for adequate management of biomass on-site (storage, quality, impurities, mixing).
Updated rules for biochar production, mainly clarifying adequate facility design elements and monitoring requirements (management of co-products, waste, air pollutants, greenhouse gases, water, health and safety).
Increased frequencies for biochar characterisation of its persistence properties and environmental properties.
Updated rules for biochar use, in particular the type of evidence required to demonstrate use has taken place with low risks of reversals, making explicit the differences for a range of uses.
Updated rules on baseline, defining three categories of biochar projects (New built, Retrofit, Charcoal Repurpose), and associated rules on indirect effects or leakage to be addressed.
Updated rules on additionality, clarifying how to handle different categories of biochar projects.
Clarifications on rules for calculation of project emissions, and change of rule on amortization of embodied emissions (5 years)
Strengthened requirements for documentation of the monitoring of the activity

2. How are environmental and social risks addressed in the methodology?

Environmental and social risks are addressed through a layered approach, starting with compliance with applicable regulations. The methodology further sets clear requirements for every stage of the activity, including biomass sourcing, biochar production, and biochar use, to prevent negative environmental impacts. In addition, regular monitoring and reporting help ensure these rules are followed and allow early detection of potential risks. Proper management of air emissions, byproducts, and residues help protect the environment. Safeguards are also in place to prevent issues like deforestation or land-use conflicts, ensuring biochar production remains a sustainable climate solution. Overall, the potential risks associated with biochar activities are fairly well-known and addressing them is the foundation to be an eligible biochar project.

3. For how long is biochar carbon removal guaranteed by Puro.earth? Why select durability of several centuries?

In this methodology update, Puro.earth suggests a guaranteed removal of several centuries, labeled as CORC200+. This represents a significant evolution compared to the previous edition where removals were guaranteed for more than a century (CORC100+). This change was enabled by advances in biochar persistence science, resulting in the previous consensus is now deemed overly conservative.

Puro.earth deemed, in alignment with various stakeholders and Puro’s Scientific Advisory Board, that the recent scientific advances and methods put forward to characterize biochar durability over millennia are not yet sufficient nor ready for use in the context of the voluntary carbon market, for a combination of reasons both scientific and operational. Nevertheless, Puro.earth supports continued research in biochar persistence science, and this is reflected in the methodology.

For further technical details and references, please consult section 6.2 in the draft released for consultation.

Note that durability of several centuries is considered permanent removal, e.g. under the EU CRCF.

4. What is the risk for carbon losses and/or reversals?

Carbon losses occur gradually over centuries as the labile components of biochar slowly decompose. The extent of these losses depends on factors such as biochar composition and the soil temperature in the region of use. Such expected carbon losses are included in the methodology, with an updated set of equations derived from the latest research on the matter.

Reversals can happen if biochar is diverted from its intended use, subjected to cascading applications where its final fate is uncertain, or burnt in certain fire events. The methodology is designed to account for these risks and implements safeguards to minimize them, ensuring long-term carbon storage.

5. What is permanence of biochar carbon storage based on?

Biochar’s carbon storage permanence is primarily based on its chemical structure. Its highly aromatic structure makes it much more durable than regular organic matter, allowing it to persist in soils for centuries. In soil, other processes also contribute to biochar permanence e.g. natural movements of biochar towards deeper soil layers, or protection by aggregates.

Scientists assess biochar’s permanence using two main approaches: decay-based models, which track how biochar breaks down over time in laboratory and fields experiments, and composition-based models, which analyze its molecular properties. Ongoing research continues to refine these models, strengthening confidence in biochar as a permanent carbon removal solution.

6. How will the transition between Edition 2022 and Edition 2025 be managed?

A Transition Plan is also released as part of the consultation, explaining how the adoption of the updated methodology will be managed by Puro.earth. We welcome feedback on this document as well. In short, Puro will distinguish between 3 types of facilities:

Already certified facilities: can continue to operate under Edition 2022 until renewal of crediting period, or upgrade to Edition 2025 earlier.
Facilities registered but not yet certified: can still pursue certification against Edition 2022, within certain strict time limits defined in the document, and otherwise need to upgrade to Edition 2025.
Facilities registered after the launch date of Edition 2025: must be certified against Edition 2025.

Your expertise is invaluable in developing this innovative carbon removal method. We look forward to your contributions to ensure a robust, scientifically sound methodology to continue scaling biochar activities globally.

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