Verra vs Isometric vs Puro
Purpose: Decision-oriented comparison of the three biochar credit paths most relevant to US / engineered-CDR producers.
Deep clusters: Verra VM0044 · Isometric Biochar Protocol · Puro.earth Overview
Also: Puro vs Other Standards (includes CSI) · CSI Global Biochar C-Sink cluster (CSI Overview · CSI GPC vs SPC Permanence Classes · CSI MRV and Emission Portfolio) · Durable CDR Quality Tiers
Facts dated 2026-09-16 research unless noted. Every quantitative claim below is sourced in the linked chapter notes or primary URLs.
One-screen chooser
| Prefer Verra VM0044 when… | Prefer Isometric when… | Prefer Puro when… |
|---|---|---|
| Buyer demands ICVCM CCP-labelled methodology credits today | Buyer demands 1000-year / Ro or burial / built modular paths | You want public price discovery (CORCCHAR/CORCX) + engineered-CDR liquidity |
| Facility is new (greenfield) and feedstock is clear waste | Facility may be existing / complex / mobile / landfill-colocated | You need New / Retrofit / Charcoal Repurpose baselines |
| You can live with 100-year horizon framing | You can fund ISO labs + (for 1000y) petrography | You want CORC200+ centuries claim without Ro yet |
| VCS ecosystem / traditional VCU buyers | Microsoft-style high-durability offtakes (e.g. Carba) | Nasdaq × Puro market infrastructure matters |
CSI / EBC-WBC track remains a fourth option when product certification + GPC/SPC C-sinks (or Artisan / EU CS-BCR) are the commercial goal — CSI Global Biochar C-Sink · CSI Overview · Puro vs Other Standards.
Detailed comparison table
| Dimension | Verra VM0044 v1.2 | Isometric Biochar v1.3 | Puro Biochar Ed. 2025 |
|---|---|---|---|
| Operator | Verra / VCS | Isometric registry + Certify | Puro.earth Oy (Nasdaq majority) |
| Unit | Removal VCU | Net CO₂e removal credit | CORC200+ |
| Horizon | 100 years | 200y or 1000y | Several centuries (200+) |
| Permanence math | Table 3 temperature defaults (0.89/0.80/0.65) | Woolf (F_{200}) or Ro≥2% × non-reactive C | Power-law decay + 80% CI; Ro encouraged not quantifying |
| Soil chemistry gate | H:Corg ≤ 0.7 | H/Corg < 0.5, O/Corg < 0.2 | Method domain (see Edition 2025) |
| Facility newness | New / greenfield (v2.0 may expand) | Project-specific; modules for mobile/distributed | New / Retrofit / Charcoal Repurpose |
| Feedstock | Waste + App. 2 | Biomass Feedstock Accounting Module | Puro Biomass Sourcing Criteria |
| Issuance trigger | VCS validation/verification cycle | Ex-post after storage | Ex-post after eligible use |
| Buffer | VCS non-permanence tools (project-specific) | Soil/burial often 0%; built 2% | No default buffer; eligibility + liability |
| ICVCM (research) | Method CCP-Approved (24 Jul 2025) | Program accreditation claimed on registry | Program CCP-Eligible (Dec 2025); biochar method not yet CCP-Approved |
| Public biochar index | — | — | CORCCHAR / CORCX |
| Auditor model | Project-engaged VVB | Isometric-approved VVB + Certify | Puro-allocated VVB |
| Architecture | Single methodology | Protocol + modules | Methodology + General Rules |
Sources: Verra VM0044 cluster; Isometric Biochar Protocol cluster; Puro Biochar Methodology Edition 2025; Puro vs Other Standards.
Permanence science split (the real intellectual difference)
| Camp | Who | What buyers hear |
|---|---|---|
| Inventory / temperature / 100y | Verra Table 3 ← IPCC App. 4 | Familiar IPCC language; shorter formal horizon |
| Decay model / centuries | Puro CORC200+; Isometric 200y | EU CRCF-adjacent “permanent” centuries narrative |
| Inertinite / Ro millennial | Isometric 1000y (Ro≥2%); CSI upper GPC (Ro≥3.8% or HyPy≥90%) | Petrographic proof; higher lab cost; premium durability story — CSI GPC vs SPC Permanence Classes |
Deep science: Permanence Science for Credits · models soil GHG from biochar (DOI) · inertinite permanence benchmark (DOI).
Facility & feedstock design constraints
New vs existing plant
| Verra v1.x | Isometric | Puro Ed. 2025 | |
|---|---|---|---|
| Brand-new kiln | ✅ | ✅ | ✅ |
| Retrofit / existing | ❌ until v2.0 | ✅ (project-specific) | ✅ Retrofit / Charcoal Repurpose |
Verra v2.0 consultation (15 Jul–17 Aug 2026) proposes existing-facility eligibility (consultation) — not yet active.
Waste vs broader biomass
Verra’s waste + App. 2 demonstration is stricter than some Puro categories and Isometric feedstock-module pathways — budget evidence early (Verra VM0044 Methodology and Eligibility).
End uses
| Path | Verra | Isometric | Puro |
|---|---|---|---|
| Soil / compost matrix | ✅ (surface mixing rules) | ✅ Soil module | ✅ Eligible uses table |
| Concrete / asphalt | ✅ Non-soil (high-tech only) | ✅ Built module (1000y) | ✅ Materials pathways |
| Landfill burial / daily cover | Not a dedicated module | ✅ Low-oxygen burial module | Check eligible-use table / rules |
| Retail / diffuse | VCS evidence burden | Mixing <50% v/v + affidavits | R3 v2 safeguards |
Integrity labels & buyer diligence
| Question | Verra | Isometric | Puro |
|---|---|---|---|
| CCP methodology approved for biochar? | Yes (v1.2, Jul 2025) | Confirm live ICVCM category status beyond program claims | Not yet (as of Dec 2025 Puro research) |
| CCP program eligible? | VCS program context | Claimed on registry | Yes (General Rules v4.2+, Dec 2025) |
| Extra checklist at verification? | CCP Eligibility Verification Report Checklist | Protocol/module evidence in Certify | Facility + Output audits |
Practical: some corporate buyers screen for CCP-labelled credits first — that currently favors VM0044 v1.2 issuances that complete Verra’s labeling plumbing (Verra VM0044 Project Cycle and MRV).
Price discovery & liquidity
| Verra | Isometric | Puro | |
|---|---|---|---|
| Public biochar index | No | No | Yes — Puro Pricing and CORC Indexes |
| Typical discovery | Bilateral VCU deals | Bilateral / offtake (e.g. Microsoft–Carba) | Indexes + platform + offtakes |
| Fee transparency | Public Verra fee schedule | Commercial / platform (not fully mirrored here) | Public fees pages |
Market context: Market Volumes and Pricing · Buyers and Offtakes · Historical Deals · Price Indexes and Benchmarks.
MRV & issuance culture
| Theme | Verra | Isometric | Puro |
|---|---|---|---|
| When credit exists | After verification of monitored period | After storage verified | After first durable eligible use + Output Audit |
| Site visits | VCS/VVB practice | Explicit pyrolysis and application visits | Facility audit on-site; output audits |
| Digital platform | Verra Registry / Project Hub | Certify + public evidence norm | MyPuro / Puro Registry |
| Double counting | VCS ownership rules | Single contractual Project Proponent | CORC ownership / use proof |
MRV Stack · Double Counting and Credit Ownership.
Example projects (illustrative, not exhaustive)
| Registry | Named example | Source |
|---|---|---|
| Verra | Reignite (VCS 4679), Odisha — first VM0044 registration | Verra |
| Isometric | Charm Range & Plains; Carba Burnsville (+ Microsoft 44k / 5y) | Charm; Carba |
| Puro | 70+ biochar projects since 2019 (Puro claim) | Puro.earth Overview |
US / Prairie-leaning angles (light — no invented farm facts)
| Operator situation | Lean |
|---|---|
| New ag-residue pyrolyzer; compost/soil offtake; wants CCP VCU badge | Verra diligence first |
| Existing kiln; needs retrofit baseline; wants index pricing | Puro diligence first |
| Landfill partner for daily cover; Microsoft-style 1000y buyer | Isometric burial |
| Concrete/asphalt customer; Ro lab access | Isometric built (or Verra non-soil if 100y + high-tech OK) |
| Stacking NRCS CPS 336 practice payments | Policy track separate — NRCS soil carbon amendment in US ag; never double-claim same tonne as credit without rules counsel |
| Already EBC/WBC; EU CRCF / GPC–SPC buyer; or Artisan geography | CSI diligence — CSI Overview · Product Standards EBC IBI |
Decision tree (compressed)
- Is the facility greenfield?
- No → drop Verra v1.x (watch v2.0) → Puro or Isometric
- Yes → continue
- Does the offtake require CCP methodology labels?
- Yes → Verra VM0044 v1.2 currently strongest biochar method approval
- Does the offtake require ≥1000y / Ro / burial?
- Yes → Isometric (or CSI upper GPC — note Ro≥3.8% bar; CSI GPC vs SPC Permanence Classes)
- Do you need public biochar price benchmarks for financing?
- Yes → Puro indexes
- Still tied? Compare feedstock evidence cost (Verra App. 2 vs Puro sourcing vs Isometric feedstock module) and lab budget (Ro or not).
Primary links
- Verra VM0044 v1.2
- ICVCM M43
- Isometric Biochar Protocol v1.3
- Isometric Soil Module v1.3
- Puro permanence explainer
- Puro indexes
- CSI C-Sink 3.3