Overview
How this pathway works
Biochar is produced by the thermal decomposition of biomass at temperatures between 300°C and 700°C in an oxygen-limited environment - a process called pyrolysis. During pyrolysis, the biological carbon fixed by photosynthesis in the biomass is converted from labile organic compounds (which would decompose rapidly in soil or atmosphere) into highly recalcitrant aromatic carbon structures that persist in soil for centuries to millennia. The carbon is not merely stored - it is transformed into a chemically distinct, thermodynamically stable form.
Under the Teravent Hybrid Carbon Standard (THS v1.0) Annex A, biochar projects earn Teravent Hybrid Credits (THCs) for the verified, durable carbon storage represented by biochar applied to soil. The pathway qualifies as Hybrid because two inseparable components must both be present: the biological carbon cycle (photosynthesis fixing atmospheric CO₂ into biomass) provides the carbon feedstock, and the engineered pyrolysis reactor converts that biomass into stable pyrogenic carbon. Neither component alone constitutes the full project - the biochar produced by the reactor must be confirmed as TBQC-compliant and verifiably applied to soil.
Four feedstock-specific methodology codes are approved under Annex A. BCH-M01 covers agricultural residue biochar; BCH-M02 covers woody biomass biochar; BCH-M03 covers sewage sludge biochar with mandatory heavy metal controls; and BCH-M04 covers co-composting with biochar for combined soil carbon and nutrient benefit. All four methodologies require TBQC compliance - the H/Corg ratio, total carbon content, and heavy metal concentrations must be verified by an accredited laboratory at each production batch.
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Class II - Material permanence. Biochar credits carry Class II Material permanence, reflecting the 100–1,000 year mean residence time of pyrogenic carbon in soil. This is substantially longer than soil organic carbon (Class I, decades) but shorter than geological storage (Class III, millions of years). Buffer pool contributions of 10–20% apply, with the specific rate determined by the H/Corg stability class of the biochar produced and the NPRR assessed at validation. High-stability biochar (H/Corg < 0.4) carries the lower end of the buffer range.
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Both components are mandatory. THS v1.0 Module 1 requires that both the biological feedstock component and the engineered pyrolysis technology component be integral to the project design. A project that applies uncomposted organic matter directly to soil (no pyrolysis) cannot register under Annex A - it would fall under soil carbon (TNS Annex C). A pyrolysis reactor producing biochar for industrial use without confirmed soil application cannot generate THC credits under Annex A either. Both the production technology and the soil application destination must be verified.
Hybrid Pathway Architecture
Two inseparable
components
THS v1.0 Module 1 defines a Hybrid pathway as one where both a biological mechanism and an engineered technology mechanism are integral to the carbon accounting - neither alone constitutes the complete project. For biochar, the dual-component structure governs how additionality, quantification, and permanence are assessed.
Biological Component
Photosynthetic Carbon Fixation
Atmospheric CO₂ is fixed into biomass by photosynthesis during crop growth, forest management, or wastewater treatment. The biomass carbon provides the raw material for the pyrolysis process. Feedstock sustainability per Teravent Sustainable Biomass Criteria (TSBC) ensures the biological component is genuinely sourced from renewable, non-degrading systems.
Technology Component
Engineered Pyrolysis Reactor
The pyrolysis reactor converts labile biomass carbon into stable pyrogenic carbon (biochar) through controlled thermal decomposition at 300–700°C under oxygen-limited conditions. Without the reactor, the biomass would decompose - releasing CO₂ within years. The reactor is the technology that transforms temporary biological storage into century-scale material storage.
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Additionality for the combined system: Under THS v1.0 Module 2, additionality must be demonstrated for the combined hybrid system - not merely for one component. It is not sufficient to show that pyrolysis is commercially justified; the project must show that the entire chain of sustainable feedstock procurement + pyrolysis + TBQC-compliant soil application would not occur without carbon finance. This combined additionality requirement is the most distinctive feature of THS v1.0 Annex A.
Quality Standards
Teravent Biochar Quality
Criteria (TBQC)
All biochar produced under THS Annex A must meet the Teravent Biochar Quality Criteria (TBQC) before it can be applied to soil and generate THC credits. TBQC are verified by an accredited laboratory at each production batch - not at project validation alone. A batch that fails TBQC cannot generate credits for that batch, regardless of the overall project registration status.
Stability Criterion - Primary
H/Corg Molar Ratio
H/Corg ≤ 0.7
The molar ratio of hydrogen to organic carbon is the primary proxy for pyrogenic carbon stability. Lower H/Corg indicates higher aromaticity and longer mean residence time. All TBQC-eligible biochar must achieve H/Corg ≤ 0.7. Biochar with H/Corg < 0.4 qualifies for the high-stability classification (MRT > 1,000 years).
Carbon Content Criterion
Minimum Organic Carbon
≥ 50% C (organic carbon)
Biochar must contain a minimum of 50% organic carbon by dry mass. This threshold excludes char-amended mineral materials and low-grade char products from carbon credit eligibility. CHNS elemental analysis per batch is mandatory to verify organic carbon content, with inorganic carbon (carbonate) measured separately and excluded from the credit calculation.
Maximum Contaminant Levels
Heavy Metal Limits (TMCL)
Per TMCL Schedule
Biochar heavy metal concentrations must fall below Teravent Maximum Contaminant Levels (TMCL). TMCL are set conservatively for agricultural soil application - below European Biochar Certificate and IBI limits in several categories. Batch-specific heavy metal analysis is mandatory; TMCL exceedance in any batch renders that batch ineligible for credit regardless of H/Corg and carbon content.
Physical Quality
Particle Size & Moisture
< 25 mm diameter · < 30% moisture
Maximum particle size of 25 mm for agricultural soil application ensures adequate soil mixing and root contact. Moisture content below 30% is required for safe storage and transport without biological degradation. Particle size distribution and moisture content are measured per batch. Fine-grained biochar (< 2 mm) is preferred for fastest soil incorporation.
Contamination Exclusion
PAH & Dioxin Limits
PAH ≤ 12 mg/kg · Dioxins ≤ 20 ng/kg
Polycyclic aromatic hydrocarbons (PAHs) and dioxins can form during incomplete pyrolysis at low temperatures or with contaminated feedstocks. Both must be analysed per batch for BCH-M03 (sewage sludge) and BCH-M04 (co-composted waste streams). Limits align with the most conservative international biochar standards.
Application Confirmation
Verified Soil Application
GPS-registered application records
THC credits are issued only for biochar that has been verified as applied to agricultural or degraded soil - not for biochar that is produced and stockpiled, sold for industrial use, or applied to non-soil substrates. GPS-recorded application coordinates, application rate (t/ha), and application date must be logged per field unit and submitted to the TCR within 60 days of application.
Biochar Stability Classes
H/Corg determines
permanence class
THS v1.0 Annex A uses the Teravent Biochar Stability Assessment Protocol (TBSAP) to assign each biochar batch a stability class based on its H/Corg molar ratio - the primary determinant of pyrogenic carbon recalcitrance in soil. The stability class determines the mean residence time credited, the stability factor applied to gross carbon content, and the applicable buffer pool contribution rate.
| Stability Class |
H/Corg Ratio |
Typical Pyrolysis Temp. |
Mean Residence Time |
Stability Factor |
Buffer Pool Rate |
| Class I - Very High |
< 0.40 |
> 550°C - high-temperature slow pyrolysis |
> 1,000 years |
0.95 |
10–12% |
| Class II - High |
0.40 – 0.55 |
450–550°C - standard slow pyrolysis |
300–1,000 years |
0.90 |
12–16% |
| Class III - Medium |
0.55 – 0.70 |
350–450°C - lower-temperature pyrolysis |
100–300 years |
0.82 |
16–20% |
| Below TBQC - Ineligible |
> 0.70 |
< 350°C - torrefaction or incomplete pyrolysis |
< 100 years |
- |
Not eligible for THC credits |
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High-temperature presumption: Biochar produced at pyrolysis temperatures consistently exceeding 500°C is presumed to achieve H/Corg < 0.4 (Class I - Very High stability) without requiring H/Corg analysis for every batch, provided: (1) the reactor has calibrated temperature monitoring logging at ±10°C accuracy, (2) minimum pyrolysis residence time at ≥500°C is confirmed, and (3) H/Corg analysis is conducted on a statistically representative sample of minimum 10% of batches to confirm the presumption holds. This reduces laboratory cost burden for well-characterised, consistently operating reactors.
Governing Standard
THS v1.0 - Annex A
This pathway is governed exclusively by the Teravent Hybrid Carbon Standard (THS v1.0). All requirements - hybrid definition, combined additionality, TBQC compliance, stability assessment, MRV, and credit issuance - are defined within THS v1.0 and Annex A. No external standard is referenced or incorporated.
TCR›
THS v1.0›
Annex A - Biochar Production & Soil Application›
BCH-M01 through BCH-M04
M01
Hybrid definition met - biological feedstock carbon + engineered pyrolysis reactor both integral · Neither component alone constitutes the project
M02
Combined additionality for the full system - not just one component · Regulatory surplus + financial (full chain cost-benefit) + common practice (<20%)
M03
TBQC per batch mandatory · H/Corg ≤ 0.7, min. 50% C, TMCL · CHNS analysis + heavy metals at accredited lab · Stability class determines permanence factor
M04
Class II Material permanence · Buffer 10–20% by stability class and NPRR · GPS-verified soil application mandatory for credit issuance
M05
Technology risk disclosure mandatory · TSBC feedstock sustainability confirmed per batch · BCH-M03 sewage sludge: enhanced heavy metal monitoring + food safety assessment
M07
THC serial: TCR–THS–BCH–[Country]–[ProjectID]–[Vintage]–[StabilityClass]–[Unit] · Stability class encoded in serial for buyer transparency
Teravent Hybrid Credit - Serial Number Format (THS Annex A · Biochar)
TCR
–
THS
–
BCH
–
IN
–
00034
–
2025
–
I
–
000001
Methodologies Accepted
Four approved feedstock variants
THS v1.0 Annex A approves four biochar methodology codes, each defined by feedstock type. The methodology code determines the applicable TSBC requirements, additional contaminant testing obligations, the counterfactual fate analysis required, and any additional environmental safeguards. A pyrolysis facility processing multiple feedstock types must register each feedstock stream under the applicable BCH code and maintain separate production records and laboratory analysis by feedstock type.
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Counterfactual fate analysis is mandatory for all methodologies. Carbon credits for biochar represent the difference between the stable pyrogenic carbon stored and what would have happened to the carbon in the absence of the project. For agricultural residues that would otherwise be burned in the field (BCH-M01), this creates a very large additionality - the field burning would have released most of the carbon as CO₂ within days. For woody biomass that would otherwise have decomposed slowly in forest (BCH-M02), the counterfactual carbon release is slower and the additionality margin is smaller. The counterfactual must be documented, justified, and accepted by the VVB at validation.
BCH-M01 converts agricultural crop residues - the by-products of food crop harvesting - into stable biochar via pyrolysis. Rice husks, wheat and rice straw, sugarcane bagasse, cotton stalks, and corn stover are among the highest-priority feedstocks in India and Southeast Asia, where open field burning of agricultural residues is a major air quality and carbon problem. The counterfactual for these feedstocks - open burning - involves near-complete carbon loss within days plus significant emissions of CH₄, N₂O, black carbon, and particulates. Converting these residues to biochar instead captures approximately 30–50% of the residue carbon in stable form while eliminating the air quality impacts of field burning. This counterfactual creates a very strong additional carbon benefit per tonne of feedstock.
Feedstock
Crop residues - husks, straw, bagasse, stover
TSBC Requirement
Residue origin confirmed - no primary crop diversion
Counterfactual
Open field burning (most common) or aerobic decomposition
Pyrolysis Temp.
400–650°C recommended for H/Corg < 0.55
TBQC Testing
CHNS + heavy metals per batch - standard panel
Co-benefit
Eliminates field burning - very high air quality benefit
Key Monitoring Indicators
- Feedstock mass processed per batch (tonnes dry weight) - weighbridge records per delivery
- CHNS analysis per batch - organic carbon content, H/Corg ratio, nitrogen content for stability classification
- Pyrolysis reactor temperature log - continuous temperature recording at thermocouple positions (bed and freeboard), archived per batch
- Heavy metal analysis per batch - Pb, Cd, Cu, Zn, Ni, Cr, As, Hg (standard TMCL panel) at accredited laboratory
- Biochar yield per batch (tonnes) - production log with yield factor for mass balance check against feedstock input
- GPS application records - field coordinates, application date, tonnes applied per field unit - submitted to TCR within 60 days
- Counterfactual documentation - annual field survey confirming open burning is still the baseline management in the project geography
- Soil application depth and incorporation method - confirms biochar remains in top 30 cm and is not surface-deposited only
BCH-M02 covers pyrolysis of wood waste, forestry residues, and woody by-products - sawmill waste, forest thinnings, urban tree waste, bamboo off-cuts, and dedicated woody energy crops. Woody feedstocks typically produce higher-quality biochar than agricultural residues - higher aromatic carbon content, higher H/Corg stability for equivalent pyrolysis temperature, and lower contaminant risk. TSBC for woody biomass requires confirmation that the feedstock is a genuine by-product of timber or forest management activities and does not drive additional forest harvesting. Chain-of-custody documentation from the wood source is mandatory.
Feedstock
Sawmill waste, forestry residues, wood waste
TSBC Requirement
Chain-of-custody from certified forest or verified waste stream
Counterfactual
Aerobic decomposition in landfill or forest - slower baseline release
Typical H/Corg
0.35–0.50 at 500°C - high stability range
Carbon Yield
25–35% of dry feedstock mass as biochar
No Primary Forest
Primary forest or intact natural forest feedstocks excluded
Key Monitoring Indicators
- Wood feedstock mass per batch with origin documentation - FSC, PEFC, or Teravent-verified chain-of-custody certificate per delivery
- CHNS per batch - H/Corg, total organic carbon, ash content for stability and credit calculation
- Pyrolysis temperature log - continuous thermocouple data showing batch temperature profile against target specification
- Heavy metals - standard TMCL panel; timber treated with preservatives (CCA, creosote) requires enhanced testing for Cr, As, Cu
- Biochar yield and mass balance per batch - confirms no undisclosed diversion of biochar to non-soil uses
- Soil application GPS records with depth of incorporation confirmed - incorporated >5 cm below surface preferred to reduce wind erosion
- Counterfactual baseline update - annual confirmation that wood waste would not have been used for bioenergy or composting absent project
BCH-M03 covers the pyrolysis of dried sewage sludge (biosolids) from municipal or industrial wastewater treatment facilities. Sewage sludge biochar typically contains elevated concentrations of plant nutrients (phosphorus, potassium, micronutrients) making it agronomically valuable - but also carries higher risks of heavy metal contamination and pharmaceutical/personal care product (PPCP) residues compared to agricultural or woody feedstocks. For this reason, BCH-M03 carries the most stringent TBQC requirements of any BCH methodology, including enhanced heavy metal testing, PAH and dioxin analysis, and a mandatory food safety assessment before soil application on food-producing land. Application on non-food-producing land (degraded land restoration, forestry) has reduced monitoring requirements compared to food crop application.
Feedstock
Dried municipal or industrial sewage sludge
Moisture Content
< 30% required before pyrolysis - pre-drying mandatory
Enhanced Testing
Full TMCL + PAH + dioxins + PPCPs per batch
Food Safety Assessment
Mandatory before application on food-producing land
Temperature Minimum
≥ 500°C required for pathogen elimination and dioxin destruction
Counterfactual
Landfill or land spreading of raw sludge - significant GHG benefit
Key Monitoring Indicators
- Enhanced TMCL panel per batch - Pb, Cd, Cu, Zn, Ni, Cr, As, Hg, Se, Mo, B (extended panel vs. BCH-M01/M02)
- PAH suite (16 EPA PAHs) - per batch, mandatory for BCH-M03
- Dioxin and furan (PCDD/PCDF) analysis - per batch; ≤ 20 ng TEQ/kg I-TEQ limit
- PPCP screening - pharmaceutical residues and personal care products at initial validation, annually thereafter
- Pyrolysis temperature - minimum 500°C holding time confirmed per batch to ensure pathogen elimination
- Application site food safety declaration - where applied to food-producing land, an agronomist-signed food safety assessment submitted to TCR before application
- Soil heavy metal accumulation monitoring at permanent plots - Cd, Pb, Hg, Ni every 3 years for food-producing land
BCH-M04 integrates biochar production with composting operations, incorporating TBQC-compliant biochar into a compost mixture before final soil application. The combined biochar-compost product delivers the stable pyrogenic carbon of biochar together with the nutrient cycling and microbial inoculant benefits of mature compost. Biochar in composting serves as a habitat for beneficial microorganisms during composting, potentially improving compost quality, while the compost matrix improves soil biochar retention after application. Credit is issued only for the biochar carbon fraction - the labile compost organic matter is not credited under THS Annex A (it may be separately credited under TNS Annex C where material SOC benefits are independently verified).
System Type
Biochar-compost combined product
Biochar Fraction
Minimum 10% biochar by dry mass of final product
TBQC Timing
Biochar tested before incorporation into compost - not after
Creditable Pool
Biochar carbon only - labile compost C excluded
Compost Quality
Compost maturity confirmed - prevents N₂O spike from immature compost
No double-count
Compost SOC benefit only under separate TNS Annex C registration
Key Monitoring Indicators
- Biochar mass incorporated per compost batch - TBQC-compliant biochar tested before addition; incorporation mass recorded per batch
- Biochar CHNS and TMCL per batch before compost incorporation - ensures TBQC compliance independent of compost mixing
- Final compost product analysis - confirms biochar fraction retained in final product; biochar not lost to windrow runoff or segregation
- Compost maturity index (C:N ratio, phytotoxicity, respiration rate) - confirms compost is fully mature before application to prevent N₂O spikes
- Application rate per field - tonnes of biochar-compost product per hectare, GPS-registered per application event
- Separation of biochar and compost carbon pools in credit calculation - separate line items in the annual verification report
- N₂O monitoring where compost application rate exceeds 20 t/ha - elevated organic N input risk assessed per Module 3
Pyrolysis Process
From biomass to
stable pyrogenic carbon
The pyrolysis reactor is the technology component that distinguishes Annex A from all nature-based soil carbon pathways. The four-stage pyrolysis process below describes the thermal transformation of biomass carbon into stable pyrogenic carbon. Reactor temperature profile, residence time, and oxygen control are the three primary determinants of biochar quality - all three must be continuously monitored and logged.
Stage 1 · Drying
Moisture Removal
100–200°C
Feedstock moisture evaporated. Must reach <30% moisture before thermal decomposition begins. Critical for uniform pyrolysis - wet feedstock causes temperature inhomogeneity.
Stage 2 · Torrefaction
Initial Decomposition
200–300°C
Hemicellulose decomposes; moisture and volatile organic acids released. Product at this stage is torrefied biomass - below TBQC H/Corg threshold. Not eligible for credits.
Stage 3 · Pyrolysis
Carbon Aromatisation
300–700°C
Cellulose and lignin decompose. Aromatic carbon networks form. H/Corg drops as hydrogen leaves with volatile gases and tars. Stability class determined by temperature achieved and residence time.
Stage 4 · Cooling
Quench & Stabilise
< 200°C (quench)
Rapid cooling preserves aromatic structure. Oxygen exclusion maintained during cooling to prevent combustion. Final biochar analysed for TBQC before application or storage.
Contaminant Limits
Teravent Maximum
Contaminant Levels (TMCL)
All Annex A biochar must meet TMCL before soil application. Limits are set to protect soil quality, food safety, and groundwater over the full 100–1,000 year storage horizon. TMCL are deliberately conservative - set below most international biochar standards - because Teravent credits represent long-duration soil presence, not short-cycle amendments.
| Metal / Contaminant |
TMCL Limit (mg/kg dry wt) |
Applies To |
Risk Basis |
| Lead (Pb) | 150 | All BCH codes | Human health via crop uptake; soil accumulation over century timescales |
| Cadmium (Cd) | 1.5 | All BCH codes | Very high crop uptake factor; carcinogenic - most critical TMCL parameter |
| Copper (Cu) | 400 | All BCH codes | Phytotoxicity at elevated soil concentrations; earthworm toxicity |
| Zinc (Zn) | 400 | All BCH codes | Phytotoxicity and soil microbial community disruption at high concentrations |
| Nickel (Ni) | 80 | All BCH codes; enhanced for olivine-contaminated woody feedstocks | Crop uptake; phytotoxic and nephrotoxic - elevated risk in BCH-M02 from contaminated wood |
| Chromium (Cr) | 90 (total) · <2 (Cr VI) | All BCH codes; CCA-treated wood excluded from BCH-M02 | Cr(VI) is highly carcinogenic - separate limit for hexavalent chromium required |
| Arsenic (As) | 13 | All BCH codes | Carcinogenic; bioaccumulates in rice - critical parameter for BCH-M01 rice husk biochar |
| Mercury (Hg) | 1 | All BCH codes | Highly toxic; BCH-M03 sewage sludge carries elevated Hg risk from industrial wastewater |
| PAHs (sum 16) | 12 | All BCH codes; critical for BCH-M03 | Carcinogenic; can form during low-temperature pyrolysis or with incomplete oxygen exclusion |
| Dioxins + Furans | 20 ng TEQ/kg | BCH-M03 mandatory; BCH-M01/M02 where chlorinated feedstocks possible | Persistent organic pollutants; formed at 300–600°C with chlorinated feedstocks |
Carbon Pool Accounting
What gets credited
THS v1.0 Module 3 requires all material GHG sources and removals to be quantified. For biochar, the accounting structure is relatively straightforward compared to multi-pool nature-based pathways - the primary credit source is the stable pyrogenic carbon in applied biochar, with process GHG and feedstock counterfactual as the primary accounting items.
Required - Primary Benefit
Stable Pyrogenic Carbon Applied to Soil
The mass of stable pyrogenic carbon in TBQC-compliant biochar applied to soil, adjusted by the stability factor for the applicable stability class (0.82–0.95). Calculated as: [Biochar mass applied (t)] × [Organic carbon content %/100] × [Stability factor] × [3.667 tCO₂e/tC]. This is the primary source of THC credits.
Required - Deduct
Process GHG Emissions
GHG emissions from pyrolysis reactor operation - fuel for heating, electricity consumption, pyrolysis gas flaring or combustion. Where pyrolysis gas is used as reactor fuel (autothermal operation), these emissions are substantially lower. Calculated from fuel consumption records and metered electricity at applicable emission factors per TLP v1.0.
Required - Deduct
Feedstock Collection & Transport GHG
GHG from harvesting, baling, drying, and transporting biomass feedstock to the pyrolysis facility. Calculated from transport distance and mode per TLP v1.0. For agricultural residues collected within 50 km of the reactor, these emissions are typically 5–15% of gross carbon credit. Longer transport distances must be assessed for net-positive carbon balance.
Where material - positive
Counterfactual GHG Avoided
GHG emissions avoided compared to the baseline management of the feedstock. For BCH-M01 (field burning): near-complete CO₂ + CH₄ + N₂O + black carbon avoided. For BCH-M02 (aerobic decomposition): slower CO₂ release avoided. The counterfactual benefit is real but is accounted in the overall carbon balance rather than as a separate credit pool - it improves the net benefit calculation but is not separately serialised.
Separately credited where material
Soil Organic Carbon Enhancement
Where biochar application leads to verifiable increases in soil organic carbon beyond the biochar carbon itself - the priming effect - this can be separately credited under TNS Annex C with independent VVB verification. A separate project registration under TNS Annex C is required; the SOC benefit cannot be bundled with the biochar THC issuance in the same credit serial.
Excluded
Labile Compost Carbon (BCH-M04)
For co-composting projects (BCH-M04), the labile organic carbon fraction of the compost matrix is excluded from THC credit calculation - only the stable pyrogenic carbon fraction of the incorporated biochar is credited. Labile compost carbon may be separately credited under TNS Annex C with independent verification and a separate project registration.
MRV Confidence
Measurement, reporting
& verification
Biochar MRV has a distinctive profile - production-side quantification is very high confidence (mass-in, temperature-in, chemistry-out is all readily measured), while the long-term stability verification in soil remains the principal scientific uncertainty. The H/Corg proxy for mean residence time is well-supported by field and laboratory studies but carries inherent model uncertainty at soil-specific and climate-specific levels.
Pyrolysis Production QuantificationVery High
H/Corg Stability Assessment (CHNS)Very High
Soil Application Verification (GPS)High
Permanence Confidence (H/Corg proxy)High
Feedstock Sustainability (TSBC)High
Long-Term Soil Retention VerificationMedium
🔬 Measurement Standard - THS Module 3 · Biochar
CHNS elemental analysis is the primary measurement technique for both organic carbon content and H/Corg stability ratio. All CHNS analysis must be conducted by an ISO/IEC 17025 accredited laboratory using certified reference standards traceable to international standards (NIST or equivalent). The minimum sample mass for CHNS analysis is 1 g per analysis (two replicates per batch); reported values must include measurement uncertainty. For large production facilities (>500 t/month biochar), a batch sampling protocol with minimum one representative sample per 50 tonnes of production is acceptable with VVB approval. All production records, TBQC laboratory certificates, GPS application records, and temperature logs must be archived and available for VVB audit for the project lifetime plus 10 years. No credits may be issued for biochar batches for which a TBQC laboratory certificate is not available before the VVB submits its verification report.
Additionality
Demonstrating additionality
THS v1.0 Module 2 requires additionality for the combined hybrid system - the full chain from sustainable feedstock procurement through TBQC-compliant pyrolysis to verified soil application. Additionality for only one component is not sufficient.
1
Regulatory Surplus Test
No regulation mandates the pyrolysis of agricultural residues or wood waste into TBQC-compliant biochar for soil application in any current jurisdiction. Policies requiring field burning bans (e.g. India's stubble burning restrictions) create regulatory surplus for biochar as an alternative waste management pathway - the regulation forbids burning but does not mandate biochar. Where residue management regulations exist, the regulatory surplus analysis must confirm that the regulation does not require biochar production specifically. Government programmes providing subsidies for biochar production must be disclosed and their impact assessed in the financial additionality test.
2
Financial Additionality Test - Full Chain
Carbon revenue must be necessary for the full hybrid system to be viable - feedstock procurement + pyrolysis capital and operating cost + TBQC testing + GPS monitoring + soil application logistics + VVB verification costs. The financial analysis must assess the combined cost of the entire system against the market value of biochar as a soil amendment (typically $100–400/tonne in Asian markets) plus any energy co-products (heat, syngas). Where biochar commands a premium market price as a soil amendment, the financial analysis must demonstrate that the carbon revenue remains necessary even after accounting for the soil amendment market value. Spreadsheet financial models must be available for VVB review.
3
Common Practice Test - Combined System
The combined practice of (1) collecting or procuring sustainable biomass feedstock, (2) pyrolysing it in an engineered reactor to TBQC-compliant biochar, and (3) applying the biochar to agricultural soil with GPS-verified documentation must not be common practice in the project geography without carbon finance. A survey of minimum 50 comparable biomass management operations in the same district must confirm that fewer than 20% voluntarily operate the full TBQC-compliant pyrolysis-to-soil-application chain. Simple field burning reduction or ad hoc biochar production for internal farm use does not constitute common practice under this definition.
Leakage Assessment
Leakage types & deductions
Feedstock Diversion Leakage
Competing Biomass Uses
Where agricultural residue diverted to biochar production was previously used as animal fodder, compost feedstock, or mulch - and this prior use provided environmental or food system benefits - the loss of that use must be assessed. Where residues were being burned or were genuinely without beneficial use, leakage is zero. A feedstock baseline survey confirming prior management is required at PDD stage and must be updated if feedstock sourcing geography changes.
0% where feedstock was burned or decomposing · Up to 15% where prior beneficial use documented
Market Leakage
Biomass Price & Supply Effects
Large-scale biochar projects competing for biomass feedstocks in the same regional market as bioenergy, compost, or animal feed industries may drive price increases that cause other biomass users to source from less sustainable supply chains. A market leakage assessment is required for projects processing more than 10,000 tonnes of biomass per year where the feedstock competes with other uses in the same regional market. For most small and medium biochar projects, market leakage is de minimis.
De minimis (<10,000 t/yr) · Up to 10% for large-scale projects in competitive feedstock markets
Upstream Input Leakage
Reactor Energy & Consumables
GHG from auxiliary energy inputs - reactor start-up fuel, electricity for blowers and conveyors, feedstock drying energy - must be assessed in the lifecycle GHG analysis and deducted from gross credits. For autothermal reactors using pyrolysis gas as their own fuel source, auxiliary energy inputs are minimal. Projects connected to grid electricity must apply the applicable grid emission factor.
Included in lifecycle GHG analysis per TLP v1.0 · Typically 3–8% of gross credit benefit
Soil Carbon Priming Effect
Native SOC Stimulation or Loss
Biochar application can stimulate microbial activity in soil, potentially accelerating decomposition of native soil organic carbon (negative priming) or enhancing its accumulation (positive priming). Where independent field data confirms significant native SOC changes attributable to biochar application, positive SOC changes may be credited separately under TNS Annex C; negative SOC changes must be deducted from gross biochar THC credits.
Assessed at 5-year VVB verification with SOC measurement · Credited or deducted based on verified direction
Permanence
Buffer pool & reversal risk
Biochar permanence is governed by the H/Corg-based stability class assessment. Unlike biological soil carbon, biochar cannot be reversed by a single management event - it is chemically recalcitrant and cannot be easily decomposed. The primary permanence risks are physical removal (deep tillage diluting soil biochar below measurement depth, erosion exporting biochar from the site) and combustion of biochar-containing soils in severe wildfire.
| Methodology |
Typical Stability Class |
Buffer Pool Rate |
Primary Reversal Risks |
| BCH-M01 Agricultural residue |
Class I–II depending on temperature |
12–18% |
Erosion of biochar-enriched topsoil; deep tillage dilution below credited depth; fire in dry years |
| BCH-M02 Woody biomass |
Class I (commonly H/Corg < 0.4) |
10–15% |
Erosion; deep ploughing; wildfire - woody biochar is typically highest stability grade |
| BCH-M03 Sewage sludge |
Class I–II (requires ≥500°C) |
12–18% |
Erosion; tillage; potential regulatory withdrawal of application site due to heavy metal exceedance over time |
| BCH-M04 Co-composting |
Depends on biochar fraction H/Corg |
12–20% |
Erosion; biochar fraction dilution by labile compost matrix over time; measurement uncertainty in biochar soil fraction |
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Why biochar permanence is stronger than soil organic carbon: Conventional soil organic carbon (TNS Annex C) can be fully reversed by a single tillage event in days to weeks, whereas pyrogenic carbon in soil is chemically recalcitrant - even intensive tillage redistributes biochar within the soil profile rather than destroying it. Field studies show that biochar concentrations in tilled plots remain measurable decades after application. For this reason, biochar carries Class II Material permanence (100–1,000 years) vs. Class I Biological permanence (10–100 years) for conventional SOC, despite both being in-soil carbon stores.
Eligibility Requirements
Key registration criteria
✓
Hybrid definition satisfied per THS Module 1 - both the biological carbon feedstock component and the engineered pyrolysis reactor are integral to the project and both must be operational before registration
✓
All biochar produced and applied to soil must meet TBQC: H/Corg ≤ 0.7, minimum 50% organic carbon, all TMCL within limits. CHNS and heavy metal analysis by ISO/IEC 17025 accredited laboratory per batch before application. TBQC certificates submitted to TCR before credit issuance
✓
Pyrolysis reactor temperature must be continuously monitored at ±10°C accuracy; temperature logs archived per batch and available for VVB audit; minimum pyrolysis temperature confirmed for stability class determination
✓
Biomass feedstock TSBC compliance confirmed - no primary forest, no peatland-derived feedstock, LUC GHG below 35 gCO₂e/MJ. Chain-of-custody documentation per delivery batch available for VVB review
✓
GPS-registered soil application records submitted to TCR within 60 days of each application event - field coordinates, application date, tonnes applied per field, incorporation method. Credits are not issued for biochar stockpiled or not yet applied
✓
Combined additionality for the full system demonstrated: regulatory surplus, financial additionality for the full chain (production + testing + application + verification costs), and common practice survey of minimum 50 comparable biomass operations
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Counterfactual fate analysis for biomass feedstock documented and accepted by VVB at validation - confirming what would have happened to the feedstock carbon absent the project
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BCH-M03 (sewage sludge) only: minimum pyrolysis temperature of 500°C confirmed per batch; enhanced TMCL including PAHs, dioxins, and PPCPs; food safety assessment signed by qualified agronomist before application on food-producing land
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Technology risk disclosure per THS Module 5 - material technical risks (reactor failure modes, feedstock supply disruption, quality control failures) disclosed to the TSA at registration; contingency procedures for quality failures documented in the PDD
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Lifecycle GHG assessment per TLP v1.0 demonstrating net-positive carbon removal balance - production process GHG + transport emissions must be less than stable pyrogenic carbon credited. Full LCA submitted with PDD before validation
Co-Benefits & SDGs
Sustainable Development
Goal alignment
Biochar delivers one of the broadest co-benefit profiles of any Teravent pathway - combining carbon permanence with soil health, food security, air quality (by eliminating field burning), and waste management improvements. Six SDGs are systematically tracked. Projects achieving multiple verified co-benefits may qualify for stacked quality labels.
SDG 13 · Climate Action
SDG 2 · Zero Hunger
SDG 15 · Life on Land
SDG 3 · Good Health & Wellbeing
SDG 8 · Decent Work
SDG 11 · Sustainable Cities
Soil Health+
Projects demonstrating verified soil pH improvement, increased water holding capacity, reduced bulk density, or improved microbial biomass carbon - with soil data from permanent monitoring plots submitted at each verification - are eligible for Soil Health+. The most frequently awarded co-benefit label for biochar projects globally.
Food Security+
Biochar projects on smallholder agricultural land demonstrating independently audited crop yield improvements compared to non-amended control plots - with yield records verified annually - are eligible for Food Security+. Particularly applicable in acidic tropical soils where Al toxicity limits crop productivity and biochar's liming effect delivers immediate yield response.
Air Quality
BCH-M01 agricultural residue projects in regions where field burning is the baseline management practice (Indo-Gangetic Plain, Southeast Asian rice systems) deliver a measurable air quality co-benefit by eliminating particulate matter, black carbon, CO, and NO₂ emissions from open burning. Annual monitoring of fieldburning rates in the project geography confirms the air quality benefit is maintained.
Livelihoods+
Biochar projects generating verified local employment - in feedstock collection, reactor operation, quality testing, and application - with documented income data verified annually, are eligible for Livelihoods+. BCH-M03 sewage sludge projects that also improve wastewater management outcomes in peri-urban areas are eligible for the additional Urban Sanitation co-benefit designation.
Priority geographies: India (Indo-Gangetic Plain - rice-wheat residue burning; Deccan Plateau - sugarcane bagasse; Northeast India - bamboo and forestry residues), Southeast Asia (Indonesia, Vietnam, Thailand - rice husk and sugarcane bagasse abundance; Pacific islands - coconut husk biochar), Sub-Saharan Africa (acidic Oxisol belt of West and East Africa - highest yield response to biochar soil amendment), and Australia (Western Australian wheatbelt - agricultural residue management and acid soil correction).
