Appendix
Appendix 1: Ecoinvent inputs
See the appendices of the associated GHG quantification modules for lists of ecoinvent processes used. This methodology does not introduce the use of any additional ecoinvent processes.
Appendix 2: Operating procedure for Kiln Operator
Preparation of biomass
Select Eligible Feedstock:
Use only approved biomass types (e.g., forest waste, agricultural residues, invasive species).
Ensure biomass is classified as waste (not grown for CDR/bioenergy, not usable for valuable products).
Keep records of biomass type and source (e.g., photos, invoices, or contracts).
Dry Biomass:
Measure moisture content using a calibrated handheld moisture meter immediately prior to pyrolysis.
Take at least one measurement per 100 kg of feedstock, with a minimum of 10 measurements per kiln run, distributed evenly across the biomass pile covering both its surface area and depth.
Ensure mean moisture content is below the applicable threshold: ≤20% for woody biomass, or ≤15% for any other biomass or any mixture containing non-woody biomass. No individual measurement may exceed 25%.
Upload photos of each sensor reading to dMRV as proof.
Prepare Biomass for Kiln:
Chop or chip biomass to the appropriate size for the kiln, as specified in the project's training protocol.
If using woody prunings from multiple tree or shrub species treated as a single feedstock: remove all leaves prior to loading, and document via photo that bulk density, moisture content and particle size are consistent across species.
Document biomass preparation with photos and upload to dMRV.
Conducting pyrolysis
Identify the Kiln
Scan the kiln's QR code or take a photo of its unique serial number, and upload a photo of the kiln displaying its required technical features (e.g., thermocouple placement, flame-curtain design) to dMRV before starting each kiln run.
Load Biomass:
Load dried biomass into the kiln following training guidelines for proper feeding rates.
Before loading, photograph the full biomass pile staged for the kiln run.
Avoid overloading, which can cause a drop in pyrolysis temperature or disrupt secondary combustion.
For kilns capable of continuous production, adhere to the project-defined maximum operating duration or biochar mass per kiln run.
Record Biomass Amount:
Record the amount of biomass used per kiln run using one of the following approaches:
Directly weigh biomass inputs and subtract moisture using moisture content measurements; or
Use a validated feedstock-specific biomass-to-biochar conversion ratio applied to the dry biochar output.
Monitor Pyrolysis:
Start the kiln and confirm that temperature sensors are functioning before loading biomass.
Maintain pyrolysis temperature ≥350°C throughout the entire process, excluding the ramp-up and quenching phases.
Document the process with time-stamped, GPS-tagged photos or videos of kiln operation, including biomass feeding.
Temperature sensor readings are continuously and automatically recorded by the thermocouple.
Track and record all energy or fuel used for ignition and syngas combustion within the reactor.
Quench Biochar:
Rapidly quench biochar immediately after pyrolysis is complete to minimise methane emissions.
Document quenching with time-stamped photos or short videos showing the start and end time of the quenching process.
Measure and prepare biochar samples
Measure Biochar Quantity:
Choose either the volume approach or the mass approach, consistently across all kilns for the Production Batch.
Volume approach: Fill standardized containers of predefined volume and record the number of containers produced per kiln run in dMRV.
Mass approach, bone dry: Weigh biochar before quenching using calibrated scales. Record the mass directly in dMRV.
Mass approach, post-quench: Weigh biochar after quenching using calibrated scales. Record the fresh mass in dMRV. Moisture content must then be measured on at least 3 separate samples per Production Batch to convert to dry mass.
Set Aside Biochar Subsamples for the Site Composite Pile:
After each kiln run, follow the project's predefined Sampling Plan. Take several biochar samples from different spots in the pile, and add them to the Site Composite Pile.
Continue adding subsamples to this pile from every kiln run throughout the entire Production Batch duration.
Upload photos of subsamples being set aside to dMRV, including the kiln ID/QR code, Production Batch ID/QR code, date, time, and GPS location.
Take the Site Composite Sample
This may be done by the Kiln Operator or the Kiln Supervisor
Once per Production Batch, after all kiln runs are complete, thoroughly mix the Site Composite Pile. Take subsamples and combine into the Site Composite Sample.
The remaining biochar in the Site Composite Pile may be used in an eligible permanent end use and credited.
Uploading proof to dMRV
Upload Required Data for Each Kiln Run:
Kiln run proof:
Continuous temperature curves from the thermocouple sensor (automatically measured)
Photos/videos of pyrolysis, including biomass feeding and quenching.
Biomass moisture content sensor readings (photos).
Biomass type and amount used.
Biochar volume or mass produced.
Unique identification of the kiln (QR code, serial number...).
Sampling proof:
Photos of the subsample being set aside and added to the Site Composite Pile.
QR codes of biochar bags (if applicable).
End-use proof (for all biochar delivered):
Date, GPS coordinates, and address of biochar delivery and application.
Name of user/buyer and Production Batch ID.
Time-stamped, geo-located photos of biochar application or mixing.
Flag Anomalies:
Report any known issues to the Project Developer or Kiln Supervisor, including incomplete data, unsatisfactory pyrolysis, or thermocouple failures.
Appendix 3: Operating procedure for Kiln Supervisor
Annual site visits
Schedule Visits:
Visit each kiln operator at least once per year.
Observe at least one kiln run per site during the visit.
Verify Compliance:
Confirm that biomass type and moisture content are appropriate and that moisture measurements are taken correctly.
Confirm that biomass is loaded at appropriate rates without overloading the kiln.
Confirm that temperature sensors are functioning and recording continuously.
Confirm that the combustion chamber is functioning properly and mitigating methane emissions.
Confirm that quenching begins promptly after pyrolysis and is documented with time-stamped photos or video.
Check that storage conditions for biomass and biochar are appropriate (dry, protected from contamination).
Confirm that the Kiln Operator is correctly building the Site Composite Pile with subsamples from each kiln run throughout the Production Batch.
Production Batch Composite and Representative Samples
Prepare Production Batch Composite Sample:
Collect a representative sample from the Site Composite Pile at each site from the bottom, middle, and top of the pile.
Transport the sample carefully to avoid breakage.
Keep samples from different sites separate at all times if conducting bulk density measurements (see below).
Prepare Production Batch Representative Sample:
Combine all Site Composite Samples into one pile.
Mix and recombine subsamples from different spots in the pile.
Take the final Production Batch Representative Sample.
Send for Laboratory Analysis:
Set aside part of the Production Batch Representative Sample for bulk density measurements if using the volume approach to measure the amount of biochar produced.
Send the Production Batch Representative Sample to an accredited laboratory for measurement of:
Organic carbon content (each Production Batch)
H/Corg ratio (and inertinite content and residual organic carbon, if using the 1000-year pathway) (each Production Batch)
Environmental pollutants (once per year, or anytime biomass feedstock changes).
Store Retention Sample:
Keep the remaining biochar in the Production Batch Composite Pile in a protected area as a retention sample for 2 years.
Upload Records:
Upload photos, dates, times, and QR codes to dMRV.
Bulk density measurements (volume approach)
Measure bulk density for projects using the volume-based approach.
Prepare the sample
Dry the Site Composite Pile described in the section above to 0% moisture content using one of the following methods:
Moisture analyser: use a laboratory-grade moisture analyser.
Oven drying: dry in a ventilated oven at ≥110°C for a minimum of 48 hours. Subtract the final mass from the initial mass to determine moisture content and confirm complete drying.
Measure Bulk Density:
Use containers of a standard material and predefined volume.
Use calibrated scales (digital preferred; if analog, round down values).
Measure each site’s biochar separately (no mixing).
Exclude outliers (3 standard deviations from the mean).
Calculate the final bulk density of biochar in the Production Batch as the mean of all measurements minus one standard deviation.
Upload Proof:
Upload photos of each step to dMRV.
Training and oversight
Conduct Training:
Train Kiln Operators on:
Safety protocols for kiln operation.
Biomass preparation (drying, sizing) and moisture content measurement.
Correct biomass loading rates to maintain consistent and high temperatures.
Rapid quenching.
Biochar sampling procedures.
Use of dMRV, including photo requirements, GPS tagging, and batch upload requirements.
This may be done by the Kiln Supervisor or the Project Developer.
Site Visits:
During and after site visits, or at any other time, flag any non-compliant kiln runs (e.g., secondary combustion failure, missing energy input records, missing data, improper sampling).
Report findings and required follow-up actions to the Project Developer. Provide findings to be included in the Project Developer's Quality Oversight Report.
Appendix 4: Operating procedure for Project Developer
Project setup and kiln technology management
Define Project Scope
Register the project as a single entity operating one or more kilns across one or more sites, within a single country, using the same kiln technology and dMRV approach.
Ensure all sites and kilns are under the oversight or data access of the Project Developer.
Select and Deploy Kiln Technology
Use pre-approved kiln designs from Rainbow’s published list. For new designs, submit for Rainbow and VVB approval.
Verify that all kilns employ secondary combustion reactor design, where pyrolysis gases are trapped in a dedicated chimney or chamber and combusted, and are equipped with fixed, continuously-logging thermocouples placed in the same position on all kilns.
Assign a unique, permanently affixed identifier (e.g., QR code or engraved serial number) to each kiln.
Document kiln technical features (e.g., chimney design, sensor placement) in dMRV.
Define Project-Specific Criteria at Validation
Biomass feedstock types, proof of waste or invasive species status.
Sampling and measurement protocols (e.g., H/C ratio, bulk density, methane emissions).
Training Protocol for Kiln Operators and Kiln Supervisors.
Project-specific criteria for evaluating temperature curves, including acceptable temperature ranges and durations, ramp-up period, and definition of the main pyrolysis phase. Criteria shall be designed to flag incomplete biomass drying and improper feedstock loading rates.
Select and Validate dMRV Platform
Use pre-approved kiln designs from Rainbow’s published list. For new designs, ensure the platform meets Rainbow’s requirements and can track all of the required data points.
Submit the platform for Rainbow validation before use.
Oversight of all kiln runs
Review dMRV Data
Check every kiln run for:
Temperature curves: pyrolysis zone maintained ≥350°C throughout (excluding ramp-up and quenching), and project-specific quality criteria met.
Biomass moisture content: mean at or below the applicable threshold (≤20% for woody biomass, ≤15% for all other biomass or mixed biomass), and no individual measurement above 25%.
Biomass and biochar amounts are broadly consistent with photographic evidence.
Quenching was performed promptly and documented with time-stamped photos or video.
Biochar volume or mass is recorded.
Sampling records confirm a subsample was set aside and added to the Site Composite Pile.
Alternatively, outsource the checking step to a dMRV provider.
Coordinate Biochar Sampling
Ensure Kiln Supervisors combine Site Composite Samples into the Production Batch Composite Pile and send the Production Batch Representative Sample to an accredited laboratory for:
Organic carbon content (each Production Batch)
H/Corg ratio (and inertinite content and residual organic carbon, if using the 1000-year pathway) (each Production Batch)
Environmental pollutants (once per year, or anytime biomass feedstock changes).
Flag Non-Conformities
Exclude ineligible kiln runs (e.g., incomplete data, improper pyrolysis).
Document reasons for exclusion in the Oversight Report. Note that excluded kiln runs do not count towards the Production Batch size limit.
Coordinate Methane Emission Testing
Schedule Testing:
Conduct testing annually or whenever biomass feedstock changes.
Test three representative kiln runs (same kiln type and feedstock).
Use Accredited Providers:
Ensure testing is done by organizations accredited with ASTM D7036, ISO 17025, or approved by state/regional authorities.
Document Results:
Upload methane emission measurements, proof of calibration, and a signed measurement report to dMRV or share as a separate report with Rainbow and the VVB.
Training and support
Train Kiln Operators on:
Safety protocols for kiln operation.
Biomass preparation (drying, sizing) and moisture content measurement.
Correct biomass loading rates to maintain consistent and high temperatures.
Rapid quenching.
Biochar sampling procedures.
Use of dMRV, including photo requirements, GPS tagging, and batch upload requirements.
This may be done by the Kiln Supervisor or the Project Developer.
Train Kiln Supervisors on:
All topics covered in Kiln Operator training, so that Supervisors can effectively assess and support Kiln Operators during site visits.
Biochar amount measurements, including bulk density measurement procedures and moisture content measurement using oven drying or a laboratory-grade moisture analyzer.
How to adhere to the biochar sampling plan.
Upload training records to dMRV, including:
Attendance logs.
Photos/videos of training sessions.
Test results or proof of completion.
Offer Ongoing Support:
Provide refresher training and troubleshooting support (e.g., temperature curve analysis, flame curtain quality, moisture measurement).
Quality Oversight Report
To be completed for each Production Batch.
Compile Data
List all kiln runs and their status (eligible/ineligible).
Document the cumulative biomass used, biochar produced, and biochar applied in an eligible end use, noting any discrepancies and providing justification.
Document non-conformities (e.g., missing data, improper sampling) and remediation steps.
Include any site visit findings
Summarize Kiln Supervisor observations from any annual site visits that took place during the time period in question, including findings on biomass handling, kiln operation, and sampling compliance.
List any non-conformities or failures to adhere to best practices identified during visits, and their remediation.
Submit to VVB
Provide the report to the Validation and Verification Body (VVB) for audit.
Address any VVB recommendations (e.g., additional site visits, data corrections).
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