Bio-oil in asphalt

Module name	Bio-oil in asphalt
Module category	Carbon storage
Methodology name	Biomass carbon removal and storage (BiCRS)
Version	1.0
Methodology ID	RBW-BICRS-CS-BOIL
Release date	May 28th , 2026
Status	Public Consultation

Glossary

Crude bio-oil	Bio-oil extracted from pyrolysis, that has not been treated
Processed bio-oil	Crude bio-oil that has been treated to remove water and volatile organic compounds.
Bio-bitumen	Bio-based binder derived from non-petroleum sources such as bio-oils, lignin, or other organic materials. Used to replace fossil bitumen in asphalt production or as sealant.
Fossil bitumen	Viscous, black hydrocarbon material refined from crude oil, widely used as a binder in asphalt pavements and as a sealant.
Asphalt	Composite construction material consisting of mineral aggregates (gravel, sand, crushed stone) bound together with bitumen, used predominantly for road surfacing, airport runways, and parking lots.

This is a Carbon Storage Module and covers the production of bio-oil and its use in asphalt. This module is part of the Rainbow BiCRS methodology, which allows Project Developers to choose the relevant modules for their project, and shall be used with the necessary accompanying modules.

See more details on how modules are organized in the BiCRS home page.

How to use this module

BiCRS Methodology

Eligibility and scope

Eligible technologies

This module covers projects that

• use waste and residual biomass as feedstock, according to the Biomass feedstock module; and

• meet all of the following bio-oil requirements:

Bio-oil production

• Heat biomass to at least 350°C during production.

• Capture or cleanly burn pyrolysis gasses, as outlined in the Processing and Energy Use module.

• Report methane emissions from pyrolysis, using the Processing and Energy Use module.

Bio-oil processing

• Treatment of crude bio-oil to remove water and volatile organic components according to the Risk mitigation section

• Use processed bio-oil to produce bio-bitumen meeting the Product use phase and Environmental and social safeguards requirements

Bio-oil end use

• Use bio-bitumen in the eligible permanent end use: asphalt.

Projects may be designed to prioritize biochar or bioenergy production, where bio-oil is the co-product of the pyrolysis. Such projects may still be eligible for removal Rainbow Carbon Credits under this module, if they meet all criteria outlined herein.

This module allows for issuance of removal RCCs on the basis of bio-oil end use/delivery, i.e. incorporation as bio-bitumen into asphalt, not on the basis of bio-oil production.

Eligible end uses of bio-oil under this methodology are limited to the production of bio-bitumen and its use in asphalt for road construction or paving of other areas (e.g. parking lots, airport runways, docks). Any other use of the bio-oil (e.g. as fuel) or of the bio-bitumen (e.g. in roofing applications or for sealing and insulating purposes) is not eligible.

The Project Developer and entity eligible for receiving carbon finance is the operator of the bio-oil production site. Pyrolysis and gasification equipment manufacturers or users of the bio-oil (e.g. bio-bitumen producers that do not produce the bio-oil, road construction companies) are not eligible Project Developers.

Certification requirements

Certification requirements for this module are defined in the BiCRS methodology. These cover crediting period duration, monitoring period duration, site audits, and versioning and project compliance.

Project scope

One project is defined as:

• the operation of one or more pyrolysis units, across one or more sites,

• within a single country,

• using similar types of pyrolysis units,

• operated at sites that are under the oversight or data access of a single Project Developer, regardless of whether the developer directly owns or manages each site.

The project scope is cradle-to-grave and includes all processes that result from bio-oil production and use. This includes but is not limited to the following: all removals from bio-oil production, and all induced emissions related to biomass sourcing, leakage, upstream and downstream transport, embodied emissions from infrastructure and machinery, and onsite processing and energy use emissions from biomass conversion, bio-oil processing, and bio-bitumen production.

Any processes that would have occurred regardless of the bio-oil production and usage activities may be excluded from the project scope.

Baseline scope

The baseline for RCCs from bio-oil carbon removal shall include any permanent carbon removal that would have occurred in the absence of the project. This includes but is not limited to permanent carbon storage from the alternate fate of the biomass feedstock used for pyrolysis. It shall be assumed by default that no biomass feedstock would have been used to produce bio-oil in the absence of the project (i.e. there is no share of the project activity in the baseline scenario).

Product use phase

To reduce the environmental impact of asphalt production, bio-oil derived bio-bitumen has been proposed as a renewable substitute for fossil bitumen. Project Developers shall identify the type of conventional bitumen and its function that the project's bio-bitumen replaces (e.g. paving grade bitumen, penetration grade bitumen, cutback bitumen, ...). They shall justify that the project's bio-bitumen meets the same quality and performance standards as the conventional bitumen it replaces, considering

• penetration

• softening point

• viscosity

• other relevant performance characteristics related to bio-bitumen use in asphalt

Project Developers shall prove this using representative test results from pilot testing, R&D laboratories, or full-scale operations.

Project Developers shall ensure compliance of the bio-bitumen with relevant national/regional or industry standards for bitumen (often referred to as binder) in road construction (e.g. EN 12591:2009, ASTM D946). This shall also include compliance with hazard classification and pollutant levels for bitumen in road construction, as detailed in the Environmental and social safeguards section.

Compliance shall be demonstrated once per bio-bitumen batch (see Production batches for further details on the batch definition).

The baseline scenario structure remains valid for the entire crediting period but may be significantly revised earlier if:

• The Project Developer notifies Rainbow of a substantial change in project operations or baseline conditions, and/or

• The methodology is revised, affecting the baseline scenario.

The specific values within the baseline scenario will be updated during each crediting period, using project data to accurately reflect the equivalent of the project’s operations.

Production batches

A production batch is the processed bio-oil produced under the same conditions regarding

• biomass feedstock mix,

• pyrolysis temperature,

• processing of the crude bio-oil (i.e. removal of water and volatile organic compounds, see Reversal risk assessment section below).

It is assumed that all bio-oil from the same production batch has similar characteristics (i.e. thermally stable fraction, organic carbon content).

Pyrolysis temperature and biomass feedstock composition must not change by more than 20%.

Measurements and reporting are performed at the production batch level. Verification and credit issuance may be done per production batch, or annually on the cumulative production batches from that year.

For example, if the declared pyrolysis temperature is 600°C, temporary fluctuations between 480 °C and 720°C are acceptable.

If a mixture of 50% tree clippings and 50% nut shells is pyrolyzed, the proportions can vary between 40% and 60% (±10% of the original 50%)

A production batch has a maximum validity of 365 days, after which bio-oil shall be considered part of a different production batch even if conditions are unchanged. In other words, the production batch ID number resets and a new production batch is created, and new monitoring requirements applied, after 365 days, regardless of if feedstock, pyrolysis conditions or processing steps change or not.

Bio-bitumen batch

A bio-oil production batch may be used to produce one or more bio-bitumen batches. A bio-bitumen batch is defined as all bio-bitumen produced from the same bio-oil batch using the same type and amount of additives and the same production conditions (e.g. temperature, mixing time).

Amount and additive composition must not change by more than 20%.

A single bio-oil batch may be turned into multiple bio-bitumen batches if additives or processing conditions change, or correspond to a single bio-bitumen batch if conditions remain unchanged.

Principles & requirements

The principles and requirements specific to this module are detailed in the sections below. Other principles and requirements shall be taken from the accompanying modules and methodologies:

BiCRS methodology

• Additionality

• No double counting

• Environmental and social safeguards

Other modules

• Co-benefits

• No double counting

• Environmental and social safeguards

• Leakage

Durability

Durability threshold

All projects certified under this module shall prove durable carbon removals from bio-oil for at least 100 years.

Reversal risk assessment

This module covers the production of bio-oil derived bio-bitumen and its use in asphalt.

Asphalt is a composite paving material consisting of mineral aggregates like gravel, crushed stone, and sand, bound together by bitumen, a dark, viscous petroleum-derived binder. It is also referred to as asphalt concrete or blacktop.

Asphalt, more precisely the bitumen in it, ages continuously from the moment of production, through mixing and laying, and throughout decades of road service through three main mechanisms:

• distillative aging: The low-boiling components of the bitumen evaporate, mainly during hot mixing and paving (hot mix asphalt, HMA, up to 190°C) but also to a small extent at elevated temperatures in the use phase.

• oxidative aging:

• structural aging:

Distillative aging is the most relevant risk of non-permanence for credited carbon removals, as it results in the release of carbon-containing molecules.

Hence, the major carbon reversal risks from bio-oil to bio-bitumen for asphalt are:

1. Distillative aging of bio-bitumen, where light organic compounds in the bio-oil used for bio-bitumen production vaporize during the production and use-phase of asphalt due to elevated temperatures, resulting in release of stored carbon.

2. Failure to durably incorporate bio-oil into asphalt, where bio-oil does not end up in a durable storage matrix (i.e. as bio-bitumen for asphalt production) and is instead lost or degraded due to inappropriate use (e.g. as fuel) or storage.

This module establishes the following mandatory project design requirements to mitigate these risks, detailed in the following sections:

• using only the thermally stable fraction of bio-oil for crediting

• proof of thermal stability of bio-oil

• verification of bio-oil end use

Upon meeting these requirements for each verification and credit issuance, the risk of reversal is considered negligible for bio-bitumen for asphalt mixes. There are no further project requirements to assess reversal risks or conduct post-crediting monitoring for reversals.

All projects certified under this module shall contribute the default minimum 2% of their verified removal RCCs to the Rainbow Buffer Pool, as defined in the Rainbow Standard Rules.

Risk mitigation: Thermally stable fraction for crediting

Not all biomass carbon converted to bio-oil during the pyrolysis is expected to remain durably stored when used as bio-bitumen for asphalt. Only the thermally stable, heavy fraction is considered durable and eligible for crediting, as it will not vaporize under the production, use, and recycling conditions of asphalt, which are expected to reach a maximum temperature of 190°C (for hot-mix asphalt).

Project Developers shall demonstrate that all water and volatile organic compounds (VOC) are removed from the crude bio-oil before transforming it into bio-bitumen. This shall be demonstrated by:

• distillation at 200°C; or

• alternative technologies that demonstrate that the remaining organic carbon in bio oil is resistant to temperatures up to 200°C are evaluated on a case-by-case basis.

The organic carbon content of the resulting thermally stable fraction of the bio-oil, hereafter referred to as processed bio-oil as opposed to crude bio-oil, shall be measured by elemental analysis and used in the GHG quantification section to calculate the total carbon removals of the project.

Risk mitigation: Proof of thermal stability of bio-oil

To cross-validate the successful removal of water and VOC and prove the thermal stability of the processed bio-oil, Project Developers shall conduct the following measurement:

• Thermogravimetric Analysis (TGA) under inert gas (e.g. Nitrogen) atmosphere and up to a minimum temperature of 300°C. The cumulative weight loss up to 200°C is assumed to be 100% carbon and deducted from the gross carbon removal in Equation 2. Where cumulative weight loss up to 200°C exceeds 5%, the bio-oil batch is not eligible for crediting. Project Developers shall explain the source of any weight loss up to 200°C. See sampling and measurements section for more details.

These measurements shall be conducted at validation and repeated for every new production batch.

Limiting RCC issuance to the processed bio-oil carbon mitigates re-emission risks during asphalt production and use.

Risk mitigation: Proof of bio-oil end use

Project Developers shall prove that all processed bio-oil has been used in the intended durable storage application (i.e. as bio-bitumen in asphalt). This shall be done in Bio-oil Use Verification Reports that contain all of the following:

• Details of the bio-bitumen production, specifying bio-bitumen batch ID, the type and amount of additives used, the production conditions (e.g. temperature, mixing time) and the , and corresponding Production Batch ID of the processed bio-oil used.

• Sales and/or delivery records of the bio-bitumen to asphalt production companies, specifying the date, amount of bio-bitumen and corresponding bio-oil Production Batch ID.

• Signed agreements with the buyer/user of the bio-bitumen, specifying that the bio-bitumen is solely used is asphalt production and not for any other, ineligible use (e.g. roofing, waterproofing).

• Company name and individual contact information for each buyer/user of bio-bitumen, for traceability and random checking by VVBs.

Issuing removal RCCs only after verified incorporation into a permanent storage matrix mitigates the risk that bio-oil is burned, destroyed or used in other, non-permanent end-uses, and the carbon stored in the bio-oil re-emitted.

No double counting

Project Developers shall sign the Rainbow MRV & Registry Terms & Conditions, committing to follow the requirements outlined in the Rainbow Standard Rules, including not double using or double issuing carbon credits.

Project Developers shall prove that they hold the sole ownership of the carbon removal in the asphalt, and that other parties involved in the supply chain (e.g. asphalt mixing company) do not. This includes ensuring that no other party claims the carbon removal through Environmental Product Declarations (EPDs), product-level marketing, or corporate greenhouse gas reporting.

Co-benefits

Projects should support at least two quantifiable and verifiable environmental or social co-benefits, aligned with the UN Sustainable Development Goals (SDGs) framework. Any co-benefits claimed by the Project Developer shall be quantified, monitored, and audited for each verification and credit issuance.

Common co-benefits under this methodology are detailed in the table below. Project Developers may suggest and prove other co-benefits not mentioned here.

SDG 13 on Climate Action by default is not considered a co-benefit here, since it is implicitly accounted for in the issuance of carbon credits. If the project delivers climate benefits that are not accounted for in the GHG reduction quantifications, then they may be considered as co-benefits.

Table 1 Common co-benefits that projects under this methodology may provide are detailed, including types of proof that can be used to justify each co-benefit.

UN SDG	Example	Proof
SDG 9.4: Upgrade infrastructure to make them sustainable	The use of bio-bitumen in asphalt production replaces fossil bitumen, thereby avoiding/reducing GHG emissions from asphalt production.	Verification of end use of bio-oil
SDG 12.2: Achieve the sustainable management and efficient use of natural resources	The use of bio-bitumen in asphalt production replaces fossil bitumen, thereby reducing the extraction of and the reliance on non-renewable resources	Verification of end use of bio-oil
SDG 12.2: Achieve the sustainable management and efficient use of natural resources	Sustainable reuse of biomass, avoiding open field burning of biomass or landfilling.	Type of feedstock used, verification of end use of bio-oil

Environmental and social safeguards

Project Developers shall prove that the project does not contribute to substantial environmental and social harms.

Projects must follow all national, local, and European (if located in Europe) environmental regulations, including but not limited to those related to pyrolysis, gasification, waste feedstock management, and bitumen and asphalt performance and pollutant thresholds.

Hazard comparability assessment

Project Developers shall demonstrate that the bio-bitumen produced from the project's bio-oil is not more hazardous than the conventional product it replaces.

The assessment shall be made for every bio-bitumen batch and compared against applicable regulatory classifications and thresholds for the equivalent conventional product. Where bio-bitumen does not meet the applicable requirements, the assessment may instead be applied to the final blended asphalt product, as set out below.

For the assessment, Project Developers shall:

• Identify the counterfactual product. The conventional product being replaced shall be identified (e.g. paving grade bitumen, penetration grade bitumen, cutback bitumen, ...) and its applicable regulatory classification or hazard profile documented.

• Assess the hazard classification of the bio-bitumen. The bio-bitumen shall be assessed against the same regulatory frameworks applicable to conventional bitumen. If a national or international bio-bitumen standard exists and is applicable, it shall be cited in preference to petroleum-bitumen standards. The assessment shall at minimum cover PAH content and bitumen fume emissions. If the bio-bitumen is classified as non-hazardous under those frameworks, the requirement is satisfied and no further assessment is required.

• Where bio-bitumen does not meet the applicable requirements, apply the assessment to the final asphalt product. Project Developers shall provide an explanation of why the bio-bitumen does not satisfy the requirements on a standalone basis. They may then instead apply the hazard assessment to the final traceable blended asphalt product in which the bio-bitumen is blended with conventional bitumen. The final asphalt product shall be assessed against the same regulatory thresholds applicable to conventional asphalt. If the final product meets those thresholds and is classified as non-hazardous, the requirement is satisfied.

If intermediate products like bio-oil or bio-bitumen carry a hazard classification, this does not automatically disqualify a project.

For example:

• Bio-oil with elevated acidity may still yield compliant bio-bitumen if neutralization steps (e.g. lime addition) are documented and verified.

• Bio-bitumen classified as a hazardous substance may still yield non-hazardous asphalt if dilution in the final mix brings all regulated parameters below threshold.

Acceptable evidence include

• Third-party certification of the final traceable product confirming that the product meets the applicable non-hazardous classification and/or that regulated parameters (e.g. PAH content, fume emission rate, leachate toxicity) are within permitted thresholds.

• Safety Data Sheet (SDS) documents for the project's bio-bitumen as supplied to the asphalt plant, and the finished asphalt mix incorporating it, with an explicit comparison of hazard classifications (GHS/CLP categories) showing the final product is equal to or less hazardous than the conventional product.

Environmental and social risk assessment

Project Developers shall fill in the Rainbow bio-oil to bio-bitumen risk assessment, to evaluate the identified environmental and social risks of projects. The identified risks include:

• Worker injury or illness due to exposure to hazardous substances in the bio-oil and/or bio-bitumen

• Worker injury or illness due to exposure to hazardous fumes during bio-bitumen production

• Harm to human health and environment due to exposure to hazardous substances and fumes during use-phase of bio-oil

• Leaching of hazardous substances in bio-oil and /or bio-bitumen due to improper storage

The risk assessment also includes the identified risks from the Biomass feedstock module and the risks from the Processing and energy use module relevant for this carbon storage module.

Project Developers shall assign a likelihood and severity score of each risk, and provide an explanation of their choices. The VVB and Rainbow’s Certification team shall evaluate the assessment and may recommend changes to the assigned scores.

Any identified material risk (defined as issues with a risk score of moderate or higher) shall be subject to a Risk Mitigation Plan, which outlines how Project Developers will mitigate, monitor, report, and if necessary, compensate for any environmental and/or social harms.

Additional proof may be required for certain high risk environmental and social problems.

The Project Developer, the Rainbow Certification Team, or the VVB may suggest additional risks to be considered for a specific project.

Note that the life-cycle GHG reduction calculations account for the climate change impacts of most environmental risks. Nonetheless, Project Developers shall transparently describe any substantial and sensitive GHG emission risks in the risk evaluation template.

All risk assessments must also address the Minimum environmental and social risks defined in the Rainbow Standard Rules.

Monitoring

Monitoring Plans for this module shall include, but are not limited to, tracking of the following information for each Production Batch:

• Description of the pyrolysis conditions (temperature and residence time) and any variability in the process

• Description of the process to remove water and volatile organic compounds from the crude bio-oil

• Amount of crude bio-oil produced, in tonnes

• Amount of processed bio-oil produced, in tonnes

• Amount of processed bio-oil delivered, in tonnes: Bio-oil Use Verification Reports

• Organic carbon content of the processed bio-oil

• Cumulative weight loss up to 200°C of the processed bio-oil (TGA)

• Sampling protocol

• Bio-bitumen batches

  • Number of bio-bitumen batches produced from bio-oil production batch

  • Compliance with Product use phase requirements

  • Compliance with Environmental and social safeguards: Hazard assessment requirements

Monitoring Plans for this module shall include, but are not limited to, tracking of the following information for each monitoring period:

• Number of production batches

• Number of bio-bitumen batches

• Total amount of crude bio-oil produced per year, in tonnes

• Total amount of processed bio-oil per year, in tonnes

• Total amount of processed bio-oil delivered per year, in tonnes

• Co-benefits

Monitoring Plans shall include the following information for each monitored parameter:

• monitoring frequency

• emission sources and sinks

• data source

• measurement methods/procedures, and their accuracy and calibration

• quality assessment or quality control procedures

• responsible party for collecting and archiving data

GHG quantification

The GHG quantification instructions from all other BiCRS modules used by the project must be used in conjunction with the present module in order to obtain full life-cycle GHG quantifications.

The system boundary of this quantification section starts at the recovery of crude bio-oil from the pyrolysis reaction, and ends at the delivery of bio-bitumen to the site of asphalt mixing.

Quantification shall be done at a minimum for each bio-oil production batch, and may be done more frequently for continuous issuance.

The following high-level equations shall be used to calculate carbon removals from bio-oil to asphalt projects.

Calculation removals

Note that Eq. 1 and 2 have been taken directly from the GHG Quantification section of the BiCRS methodology and are included here to improve clarity.

$\textbf{(Eq.1)}\ Net\ Removal = R_{baseline}-R_{project}-E_{project}$

where,

• $Net\ Removal$ represents the net removals from the project during the monitoring period, in tonnes of CO$_2$eq. Its sign is positive.

• $R_{baseline}$ represents any baseline GHG removals from the capture module(s), representing permanent storage that would have occurred in the absence of the project, in tonnes of CO$_2$eq. Its sign is negative.

• $R_{project}$ represents the project's gross GHG removals from the carbon capture module(s) used by the project, in tonnes of CO$_2$eq. Its sign is negative. In this module, $R_{project}$ is calculated using Eq. 4.

• $E_{project}$ represents the project's total induced GHG emissions across the project life cycle, in tonnes of CO$_2$eq. Its sign is positive.

$\textbf{(Eq.2)}\ E_{project} = {E}_{project,\ Capture} + {E}_{project,\ Transformation}+ {E}_{project,\ Storage}$

where,

• $E_{project}$ was described in Eq. 1.

• $E_{project,\ Capture}$ represents the project's GHG emissions from the capture module(s) used by the project.

• $E_{project,\ Transformation}$ represents the project's GHG emissions from the transformation module(s) used by the project.

• ${E}_{project,\ Storage}$ represents the project's GHG emissions from the storage module(s) used by the project.

See the Co-product allocation section in the BiCRS methodology and in this module for further information on how baseline removals and project emissions are allocated between co-products (e.g. biochar and bio-oil)

GHG quantification is performed for each Production Batch, based on the amount of processed bio-oil, but removal Rainbow Carbon Credits (RCCs) are issued on the basis of processed bio-oil delivery and application in an eligible end use. The following equation is used to determine the number of RCCs to issue per monitoring period, accounting for a potential delay in bio-oil use after production. See the Functional unit section for more details.

$\textbf{(Eq.3)}\ Removal\ RCCs= \frac{Net\ removal}{tonne\ bio-oil\ produced} \times tonne\ bio-oil\ delivered$

Where

• $Removal\ RCCs$ represents the number of removal credits to be issued at the end of the monitoring period.

• $Net\ removal$ is defined in the GHG Quantification section of the BiCRS methodology.

• $tonne\ bio-oil\ produced$ represents the amount of processed bio-oil produced in the entire Production Batch.

• $tonne\ bio-oil\ delivered$ represents the amount of processed bio-oil delivered in an eligible end use in the monitoring period, for the given Production Batch.

Functional unit

The functional unit shall be 1 tonne of processed bio-oil produced.

Input data shall be provided for all processes related to bio-oil production in the given Production Batch, and net project removals are first calculated for all processes across the entire duration of the Production Batch.

This is normalized to net removals per functional unit by dividing by the amount of processed bio-oil produced in the Production Batch.

The number of credits to issue in the given monitoring period is calculated by multiplying the amount of processed bio-oil applied in an eligible end use (i.e. bio-bitumen for asphalt production), by the net removals per tonne of processed bio-oil produced.

This approach is detailed in Eq. 1-3 above .

Data source

The required primary data for GHG reduction calculations from projects are presented in Table 2. These data shall be provided either for each monitoring period or each production batch, as indicted in the table, and made publicly available.

Table 2 Summary of primary data needed from projects and their source for initial project certification and validation. All primary data sources listed here are required to be monitored and updated during verification (see Monitoring Plan section).

Parameter	Unit	Source
Total amount of crude bio-oil produced in the monitoring period	Tonnes	Internal tracking documents
Total amount of processed bio-oil produced in the monitoring period	Tonnes	Internal tracking documents
Total amount of processed bio-oil delivered as bio-bitumen to the asphalt producer in the monitoring period	Tonnes	Bio-oil use verification record
Amount of crude bio-oil produced per production batch	Tonnes	Internal tracking documents
Amount of processed bio-oil produced per production batch	Tonnes	Internal tracking documents
Amount of processed bio-oil delivered per production batch	Tonnes	Bio-oil use verification record
Organic carbon content of processed bio-oil per production batch	Fraction	Laboratory chemical analysis
Cumulative weight loss up to 200°C (TGA) of processed bio-oil per production batch	Fraction	Laboratory chemical analysis

No other secondary data sources are used in this module.

Co-product allocation

The rules outlined at the methodology-level in the BiCRS methodology document shall be applied for allocating baseline removals and induced GHG emissions from shared processes between pyrolysis co-products (e.g. biochar and bio-oil). This shall include at least the following:

• baseline removals from the Biomass feedstock module

• emissions from

  • biomass transport

  • biomass processing

  • methane emissions

  • embodied emissions from infrastructure and machinery

All GHG emissions from processes after the point of co-product generation and solely serve the bio-oil are attributed in full to the bio-oil production. This shall include at least the following:

• crude bio-oil processing

• bio-bitumen production

• any transport, e.g. of bio-oil to bio-bitumen production facility, or of bio-bitumen to asphalt mixing company.

For example, a project's produces both biochar and bio-oil via pyrolysis. The biochar and the bio-oil can be used for carbon removal and be issued removal RCCs. The total carbon storage from bio-oil is 400 tCO₂ eq (= 40%) and from biochar is 600 tCO₂ eq (= 60%).

Baseline removals

In the basence of the project, 10 tCO₂ eq would have remained stored in the soil due to biomass degradation. They are allocated to the co-products based on their total carbon storage capacity.

• Biochar, 60% of total carbon stored = 60% of baseline removals = 6 tCO₂ eq

• Bio-oil, 40% of total carbon stored = 40% of baseline removals = 4 tCO₂ eq

Shared process emissions

Emissions from biomass transport, biomass processing, methane emissions from pyrolysis and embodied emissions from infrastructure and machinery amount to 200 tCO₂ eq and are allocated to the co-products accordingly:

• Biochar, 60% of total carbon stored = 60% of emissions from shared processes = 120 tCO₂ eq

• Bio-oil, 40% of total carbon stored = 40% of emissions from shared processes = 80 tCO₂ eq

Biochar-only emissions

Emissions of 30 tCO₂ eq from biochar delivery and soil application occur after the co-products are split. The processes serve only the biochar production and are attributed in full to biochar.

Bio-oil-only emissions

Crude bio-oil processing, bio-bitumen production and delivery similarly occur after the split point of the co-products and serve only the bio-oil stream. Their full emissions of 20 tCO₂ eq are attributed entirely to the bio-oil production.

Net removals

• Biochar production: (- 6 baseline carbon storage - 600 total carbon storage + 150 project emissions) tCO₂ eq = -456 tCO₂ eq

• Bio-oil production: (- 4 baseline carbon storage - 400 total carbon storage + 100 project emissions) tCO₂ eq = -304 tCO₂ eq

Assumptions

• Asphalt production and any subsequent asphalt recycling cycle happens at a maximum temperature of 190°C.

• Distillation of the crude bio-oil at 200°C (or other similar, approved procedures) removes all water and volatile organic compounds from the crude bio-oil.

• In the TGA measurement, the cumulative weight loss up to 200°C is 100% carbon.

• All processed bio-oil from the same production batch has the same characteristics (e.g. organic carbon content, pollutant levels).

Baseline scenario

The baseline shall include any permanent carbon storage that would have occurred in the absence of the project. It is assumed that there is no significant share of the project activity already occurring in business-as-usual. Therefore, the baseline for removal credits is zero and is omitted from calculations.

The baseline shall be revised at least every 5 years. A more conservative baseline scope may be applied on a case-by-base basis. It must be representative and transparently justified.

Note that baseline scenario carbon sequestration may be included for the project from the biomass feedstock module.

Project scenario

The total removals of this module are calculated according to the following Equation 4

$\textbf{(Eq.4)}\ R_{total}=\sum_{i=1}^{n} (C_{org,\ i}* A_{bio-oil,\ i}*C\ to\ {CO}_{2}*(1-W_{loss, i}))$

• $R_{total}$ represents the total carbon removals from bio-oil during the monitoring period, in tonnes of CO$_2$eq. This value shall be applied to Equation 1 from the General BiCRS methodology to calculate total project removals.

• $n$ is the total number of production batches $i$ from which bio-oil has been delivered during the monitoring period.

• $C_{org,\ i}$ represents the organic carbon content of the processed bio-oil in production batch $i$.

• $A_{bio-oil,\ i}$ represents the amount of processed bio-oil produced in production batch $i$ during the monitoring period, in tonnes.

• $C\ to\ {CO}_{2}$ is 44/12 = 3.67, and represents the molar masses of CO$_2$ and C respectively, and is used to convert tonnes C to tonnes of CO$_2$eq.

• $W_{loss,\ i}$ represents the cumulative weight loss up to 200°C of the processed bio-oil in production batch $i$.

Uncertainty assessment

An uncertainty assessment is presented below for all aspects of GHG quantification set at the methodology level. The findings from this assessment are then applied at the project level, where project-specific GHG quantification also undergoes an uncertainty assessment.

The overall project GHG quantification uncertainty is determined by qualitatively combining both the methodology-level and project-specific uncertainties for each identified source of uncertainty.

The uncertainty of the assumptions presented in the Assumptions section are assessed at the methodology level:

• Asphalt is typically produced or recycled via the hot-mix (160–190°C), warm-mix (~20°C below hot-mix), or cold-mix route (ambient temperature). The assumption carries medium to high uncertainty, as asphalt production mixes are country- or region-specific. However, assuming all asphalt is hot-mix asphalt (HMA) and that bio-bitumen is processed at 190°C throughout its entire life cycle represents the most conservative approach, as asphalt producers are expected to operate at lower temperatures wherever possible to reduce energy consumption. This assumption therefore carries low uncertainty.

• Appropriate processing of the crude bio-oil (e.g. distillation at 200°C) removes all water and VOCs, leaving behind only the thermally stable fraction of the bio-oil. This assumption is inherently high uncertainty; however, the requirement for thermogravimetric analysis (TGA) to assess the validity of this assumption for each production batch reduces this to moderate uncertainty.

• Any cumulative mass loss up to 200°C in TGA is assumed to be 100% carbon. In practice, bio-oil typically contains around 40-70% carbon by weight, the volatile fraction removed below 200°C is therefore not pure carbon. This assumption carries high inherent uncertainty. However, it also underestimates the carbon retained in the bio-bitumen and is therefore considered conservative from a carbon accounting perspective, resulting in low uncertainty.

• All processed bio-oil within a production batch is assumed to have uniform characteristics. This assumption carries moderate uncertainty.

The uncertainty at the methodology level is estimated to be medium. This translates to an expected discount factor of at least 6% for projects under this methodology.

Sampling and measurements

The following indicators shall be measured for each production batch:

• Amount of processed bio-oil produced and delivered

• Organic carbon content of processed bio-oil

• Cumulative weight loss up to 200°C (TGA) of processed bio-oil

Measurements shall be performed by laboratories with at least one quality assurance accreditation, such as:

• ISO/IEC 17025

• CEN/TS 17225-1

• ISO 10694

Unaccredited laboratories from academic settings shall be evaluated on a case by case basis by the VVB and the Rainbow Certification Team.

Representative sampling

Bio-oil composition is variable and changes over time due to its reactive nature. The following requirements ensure that samples are representative of the bio-oil material that enters bio-bitumen production, and that measurements are sufficiently frequent to capture this variability.

• A sample shall be taken once every 100 tonnes of processed bio-oil produced, or once per production batch, whichever comes first, for the first 1,000 tonnes of production.

• After 1,000 tonnes of processed bio-oil have been produced, the sampling frequency may be relaxed to once every 250 tonnes, provided that measurement stability has been demonstrated. To demonstrate stability, Project Developers shall conduct a statistical analysis of prior measurements and show that results do not vary by more than ±5%. If this criterion is not met, the reduced frequency is not permitted.

• Samples shall be taken and analysed after a storage duration equal to the average storage duration of bio-oil before it enters bio-bitumen production, within a tolerance of ±1 week.

• Samples shall be taken from a homogeneous portion of the bio-oil, ensuring that all phases and solids are fully blended prior to sampling.

For each production batch, Project Developers shall provide a sampling protocol that includes, at minimum:

• the number of samples taken per production batch;

• a statistical analysis of the variability of measurement results;

• the average storage duration of bio-oil prior to bio-bitumen production;

• the duration between bio-oil production and sampling for every sample;

• desciption of the sampling procedure.

Measurements

• The organic carbon content of the bio-oil shall be determined by elemental analysis following the ASTM D5291 standard test method or equivalent, if justified and documented. The measurement shall be done in replicates of three.

• Thermogravimetric analysis shall be conducted in a temperature range from room temperature to a minimum of 300°C under an inert gas atmosphere (e.g. N₂) and with a temperature ramp rate of 10°C/min. The measurement shall be done in replicates of three and the cumulative weight loss up to 200°C reported.

Risk assessment template

This module uses the risk assessment template version 1.0

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