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Distributed open-kiln and closed-kiln biochar Carbon Credit Methodology- Public Consultation

Rainbow is a carbon crediting standard, and we’re excited to announce a 30-day public consultation on our Distributed open-kiln biochar and Distributed closed-kiln biochar methodologies. This consultation is part of our ongoing commitment to transparency and collaboration in the development of each methodology.

This methodology was developed by Rainbow with the support of the Rainbow Distributed biochar Working Group members and other expert contributors.

The goal of this consultation is to gather input from a broad range of stakeholders to ensure the methodology is both scientifically sound and practically applicable. We aim to strike a balance between methodological rigor and feasibility, keeping in mind the real-world challenges that project developers and other stakeholders face.

Thank you for contributing to the future of carbon crediting! 🙏

Why do you have an interest to participate?

✔️ Ensure the methodology meets the scientific rigor needed for issuing high-quality carbon credits

✔️ Ensure the methodology is feasible to implement

✔️ Ensure we enable a wide range of distributed biochar projects/technologies to use the methodology

How to answer this consultation?

✔️ You can complete the form in multiple sessions (your answers will automatically be saved).

✔️ Some questions are mandatory (marked by a "*") because they are pivotal for us. The other questions are optional (but any additional answer is highly appreciated!).

✔️ This consultation is divided in 3 sections: first some key questions for us, second some optional questions, third open comment on each sections of the methodology.

⏱️ Only the first section is mandatory and should take you around 15 minutes to answer.

Timeline

This consultation will be open until at least March 11th. We will build on the results to publish the finalized V1.0 of the methodology by May 2026. This timeline is purely indicative.

Where to find the document to review

You can access the draft methodologies shared for public consultation here:

👉 Distributed open-kiln biochar

👉 Distributed closed-kiln biochar

Note that the Distributed open-kiln biochar methodology and the Distributed closed-kiln biochar methodology have large overlaps with one another. For reference, here are the points of divergence:

👉Kiln design:

✅Closed kiln: Must trap and concentrate pyrolysis gases in a separate chimney or chamber, exposing them to oxygen and high temperatures to combust them before emission.

✅Open kiln: Must be cone-shaped with a minimum 2 m diameter and 1.5 m height.

👉Photo proof in dMRV:

✅Closed kiln: No additional requirements.

✅Open kiln: Must provide photos of the pyrolysis process, flame curtain, quenching, and ensure the flame does not exceed 0.5 meters above the biomass.

👉Maximum production volume per kiln:

✅Closed kiln: 1,500 m³ of biochar annually. ✅Open kiln: 500 m³ of biochar annually.

👉Inputs

✅Closed kiln: Must provide energy inputs for any syngas combustion. ✅Open kiln: No additional requirements.

Apart from these points, the methodologies are the same! You can give feedback on both methodologies at the same time.

Sign up for the consultation

Please provide some details for transparency reasons

First name

Last name

Email address

Organization

Thank you very much for your time in helping us build consensus around this methodology🙏