Rainbow: Europe's Engineered-Removal Registry Earns CCP Status
How a purpose-built CDR registry from France achieved ICVCM CCP-Eligible approval as the 9th programme, with Standard Rules v7, biochar & ERW methodologies, and production-batch crediting innovation.
By Abhishek Das • • 14 min read
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80+
Registered Projects across biochar, ERW, BiCRS & biogas
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9th CCP
ICVCM CCP-Eligible programme — first European CDR-native registry
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v7 Rules
Standard Rules v7 — CCP gate, additionality & MRV overhaul
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- 1. The Registry at a Glance
- 2. A CDR-Native Design Philosophy
- 3. Standard Rules v7: The CCP Gate
- 4. The Biochar Methodology Deep-Dive
- 5. Enhanced Rock Weathering & Emerging Pathways
- 6. BiCRS & Flexible Technology Frameworks
- 7. Permanence, Buffer Pools & Risk Management
- 8. Production-Batch Crediting Innovation
- 9. Methodology Pipeline & ICVCM Assessment Status
- 10. European Regulatory Alignment & CSRD Positioning
- 11. Competitive Landscape: Rainbow vs. Isometric & Puro.earth
- 12. FAQ: Key Questions Answered
- 13. What Developers & Buyers Should Do Now
1. The Registry at a Glance
Rainbow (formerly Riverse) is Europe's first purpose-built registry for engineered carbon dioxide removals (CDR). Headquartered in France and approved as the 9th ICVCM CCP-eligible programme in 2025, Rainbow represents a deliberate departure from traditional carbon standards that evolved from nature-based solutions and were later adapted for engineered removals.
Key Takeaway:
Rainbow's core thesis: engineered removals are not farming. They require methodologies purpose-built for precision chemistry, materials science, and novel sequestration pathways—not legacy frameworks adapted from decades of nature-based standards work.
With 80+ registered projects and over 400,000 credits already issued, Rainbow focuses exclusively on: biochar, enhanced rock weathering (ERW), biomass carbon removal and storage (BiCRS), and biogas/circular economy projects. This narrower scope—compared to mega-registries like Verra with 2,000+ projects across 20+ methodologies—enables deeper technical expertise and tighter quality controls, albeit at the cost of slower project approval and less secondary-market liquidity.
Rainbow is ICROA-endorsed and connected to the Climate Action Data Trust (CAD Trust), positioning it within emerging governance structures dedicated specifically to carbon removal integrity. This positioning appeals to buyers seeking credibility signals beyond traditional VCS accreditation.
2. A CDR-Native Design Philosophy
Rainbow was engineered from the ground up exclusively for carbon dioxide removals. This distinction is not semantic; it shapes every methodological choice, from crediting periods to permanence verification to buffer pool allocation.
Where Verra, Gold Standard, and established registries evolved from nature-based solutions (NBS) frameworks and gradually adapted for engineered removals, Rainbow rejects legacy assumptions baked in from decades of forestry and agriculture work. Traditional standards assume certain time horizons, permanence mechanisms, and baseline counterfactuals that often don't apply when biochar is stabilized in soil for 100+ years or rocks are crushed to accelerate natural weathering.
Purpose-Built, Not Retrofit
Rainbow's CDR-native architecture means its methodologies, governance structures, and crediting mechanics are designed for engineered removals from first principles—not retrofitted onto a traditional offset template. This design choice directly influences everything downstream: methodology approval timelines, permanence conservatism, and buyer appeal.
A concrete example: a French biochar producer with three production sites generating 50,000 tonnes of charcoal annually (5,000 tonnes converted to biochar for soil incorporation) would be mapped to Verra's legacy VM0015 template. Under Rainbow, it is evaluated through a cradle-to-grave biochar methodology purpose-built to address the specific durability, additionality, and crediting questions that biochar operations pose. That methodological tailoring is Rainbow's core value proposition.
3. Standard Rules v7: The CCP Gate
Rainbow's Standard Rules v7 is the registry's explicit response to ICVCM's CCP eligibility criteria. The CCP framework establishes a global baseline for core principles around additionality, permanence, non-permanence liability, monitoring, and double-counting prevention. Achieving CCP eligibility requires demonstrating that a registry's methodologies and governance structures meet or exceed those baselines. Rainbow's v7 rules were engineered specifically to achieve that alignment.
Key Takeaway:
The v7 upgrade package is not a marketing refresh—it's a substantive structural overhaul specifically engineered to meet ICVCM's Core Carbon Principles baseline. Every change addresses a credibility gap in legacy registries or a unique challenge in engineered-removals governance.
4. The Biochar Methodology Deep-Dive
Biochar—charred biomass stabilized in soil—is Rainbow's most mature offering. The methodology takes a cradle-to-grave approach: tracking carbon from biomass feedstock selection, through pyrolysis or carbonization, soil incorporation, and long-term durability.
Core permanence claim: Stabilized biochar persists in soil for at least 100 years without significant degradation, thereby sequestering carbon that would otherwise decompose or be released. Projects demonstrate 100-year durability through soil stability studies, field trials on similar soil types and climates, and peer-reviewed literature on biochar persistence. Projects can optionally claim 1,000-year permanence with additional evidence (e.g., long-term incubation studies, paleobiochar samples showing minimal degradation over millennia).
Additionality Challenge: Biochar's Counterfactual Problem
Unlike avoided deforestation (where the counterfactual is clear), biochar's counterfactual depends on what would happen to the biomass feedstock absent biochar production. Would it be burned for energy? Composted? Left to decompose? Rainbow addresses this through TRL gating, market analysis showing the producer couldn't achieve similar returns through conventional biomass use, and regulatory landscape assessment.
Credit calculation: (Biochar carbon content) × (100-year or 1,000-year permanence factor) × (1 – buffer pool %) × (uncertainty discount, typically 10-15%). The 2% buffer pool contribution is standard; this reserve covers tail-risk scenarios where soil permanence assumptions prove overly optimistic. Compared to Verra VM0044 (CCP-approved) and Isometric's biochar methodology (also CCP-approved), Rainbow's approach sits in the middle of the permanence-conservatism spectrum: more conservative than some third-party biochar methodologies, less stringent than Puro.earth's extreme permanence requirements.
Key Takeaway:
Biochar's permanence case rests on soil chemistry, not biological growth. This shifts the verification burden from long-term monitoring to front-loaded soil characterization—a strength for registries seeking faster credit issuance without sacrificing rigor.
5. Enhanced Rock Weathering & Emerging Pathways
Enhanced rock weathering (ERW) represents Rainbow's highest-risk methodological frontier. Silicate rocks (basalt, olivine, wollastonite) are crushed and spread on agricultural soils, where they react with soil acids to form carbonates—a geological process with millennial permanence. But measurement uncertainty is substantial.
Unlike biochar (where you weigh the carbon content directly), ERW requires modeling of rock dissolution rates, carbonate formation kinetics, and soil pH dynamics—all processes varying with climate, soil type, rock mineralogy, and management. ICVCM itself has flagged ERW as remaining in the "research stage" pending methodological maturation. Rainbow's ERW methodology is not yet CCP-approved as standalone; projects operate under a research/pilot framework with heavy uncertainty discounting (40-50% vs. 10-15% for biochar).
Field trials are ongoing in France and neighboring EU states, generating crucial data on carbonate accumulation rates and long-term soil impacts—but these trials will not be complete for several years. For developers, this means ERW credits issued today carry heavy discounts and face repricing risk if permanence assumptions prove overly optimistic. Budget for long-term monitoring commitments.
6. BiCRS & Flexible Technology Frameworks
Biomass Carbon Removal and Storage (BiCRS) is Rainbow's most flexible methodological framework. Where biochar and ERW address specific pathways, BiCRS provides a broader architecture for certifying projects converting biomass into stable carbon products: torrefaction, hydrothermal carbonization, biochar, advanced biofuels with permanent sequestration components, or emerging technologies. This flexibility positions Rainbow to adopt new removal technologies without full methodology rewrites.
BiCRS operates through a tiered system: Tier 1 methodologies (biochar, torrefaction, hydrothermal carbonization) are pre-approved with established rules. Tier 2 methodologies (emerging pathways) can be proposed by developers, evaluated through peer-review, and conditionally approved with enhanced monitoring. This allows methodological agility without rigor sacrifice. ICVCM assessment of BiCRS as CCP-eligible is pending, with decisions expected in late 2026.
BiCRS Flexibility: Your Advantage
If you have a breakthrough carbon removal technology—whether it's biochar with mineral amendments, novel conversion pathways, or hybrid approaches—Rainbow's tiered BiCRS framework makes methodology development faster than legacy registries. A developer could propose Tier 2 methodology and achieve CCP approval via Rainbow sooner than via Verra.
Discuss Your Technology →7. Permanence, Buffer Pools & Risk Management
Engineered removals operate on century-scale permanence horizons, creating unique challenges compared to avoided-deforestation (40-100 years) or reforestation (biological growth curves). Rainbow's v7 buffer architecture responds with differentiated permanence-class pools: separate reserves for 100-year claims vs. 1,000-year claims, and separate risk categories (technical permanence risk vs. policy/market risk).
A 2% buffer pool contribution is standard for biochar, aligning with ISO 14064-2 conventions but remaining lower than Puro.earth's premium pools (5-10%) or some competitors' reserves (Verra: 3-5%). This reserve covers tail-risk scenarios; if a particular project's permanence claim is later invalidated through long-term monitoring, the buffer pool can retire corresponding credits, protecting ecosystem integrity.
Key Takeaway:
Rainbow's differentiated buffer pools mean that a single badly-behaved project (where permanence fails) doesn't invalidate the entire permanence ecosystem. Risk is pooled by permanence class and risk category, enabling more precise tail-risk management.
8. Production-Batch Crediting Innovation
One of Rainbow's most distinctive design choices is its departure from fixed multi-year crediting periods (typically 5-7 year blocks) toward production-batch crediting: credits are issued per discrete production batch of the engineered removal activity. For biochar, a single production run from a pyrolysis facility. For ERW, a crushing and application of silicate rocks across defined land in one season.
Why this matters: Each production batch is discrete, physically separated in time and space, with its own feedstocks, process parameters, and environmental conditions. By crediting per batch rather than multi-year blocks, Rainbow achieves tighter measurement precision, reduces baseline uncertainty (each batch is independently verified, not extrapolated), and enables dynamic crediting as process improvements emerge. A facility improving its carbonization efficiency mid-year immediately increases credit issuance—not waiting for a 5-year block end.
From a permanence perspective, production-batch simplifies monitoring. Unlike Verra reforestation projects verified over 40 years, Rainbow biochar projects can front-load monitoring in the first 5-10 years, letting soil data characterize whether biochar is persisting as expected. A single poorly-behaving batch doesn't invalidate subsequent batches; it triggers enhanced scrutiny for future production.
9. Methodology Pipeline & ICVCM Assessment Status
As of early 2026, Rainbow's own methodologies are in the ICVCM assessment pipeline. This distinction matters: the registry is CCP-approved, but individual credits cannot be branded as "CCP-eligible" until the specific methodology under which they were issued is approved by ICVCM.
Key Takeaway:
Once Rainbow's biochar methodology achieves CCP approval (expected Q3-Q4 2026), the discount relative to already-approved competitors like Verra VM0044 or Puro.earth should narrow or disappear, assuming equivalence in permanence claims and uncertainty factors.
Timeline: Biochar methodology is furthest along, with CCP assessment submission expected Q2 2026 and approval decision likely Q3-Q4 2026 (typical ICVCM assessment: 6-12 months). BiCRS framework is in preliminary assessment, potential CCP evaluation in late 2026/early 2027. ERW remains in "research stage" with no imminent assessment pending field trial data completion (expected 2027-2028). Biogas/Circular Economy pillar has not yet submitted for formal ICVCM consideration.
10. European Regulatory Alignment & CSRD Positioning
Rainbow's French headquarters is not incidental—it is integral to its regulatory positioning. The EU's Corporate Sustainability Reporting Directive (CSRD) mandates double materiality sustainability reporting for large EU companies (and increasingly, non-EU companies with significant EU operations), driving intense demand for high-integrity carbon removal credits that credibly contribute to science-based net-zero targets.
Rainbow explicitly aligns with these regulatory frameworks in several ways. First, biochar and BiCRS projects in France and neighboring EU member states can engage the French Ministry for Ecological Transition (Ministère de la Transition Écologique) for additional validation and verification. This ministry endorsement, while not required, grants regulatory credibility particularly valuable for EU-regulated buyers. A French biochar producer can leverage both Rainbow and Ministry certification to signal maximum policy alignment.
Second, Rainbow's methodology selection reflects EU policy priorities. Biochar is explicitly listed in the EU's proposed Carbon Removal Certification Regulation (CRCR) as eligible. ERW research is funded through multiple EU Horizon Europe grants, positioning it as strategic European technology. Biogas with integrated biochar aligns with EU circular economy and waste-to-resource strategies. By concentrating exclusively on these pathways, Rainbow positions itself as the "EU-first" registry for engineered removals.
Third, Rainbow's connection to the Climate Action Data Trust (CAD Trust)—a European governance initiative for carbon market transparency and integrity—signals investment in EU-aligned governance structures that many corporate sustainability professionals perceive as more trustworthy than legacy standards for engineered removals.
The Double-Edged European Sword
While EU buyers increasingly demand high-integrity removal credits, and Rainbow's EU positioning appeals to this demographic, regulatory alignment may constrain global market appeal. An Indonesian biochar producer or Kenyan rock-weathering project can register with Rainbow but won't gain the same regulatory credibility signals as EU-based projects. Rainbow's addressable market is premium but geographically concentrated.
11. Competitive Landscape: Rainbow vs. Isometric & Puro.earth
The CCP-eligible engineered-removals market is crystallizing into a three-player dynamic: Rainbow, Isometric, and Puro.earth. Verra is CCP-approved but its dominance in traditional offsets dilutes its premium removals positioning. The three specialists each occupy distinct competitive positions.
This three-way segmentation means Rainbow does not directly compete for Isometric's volume-focused buyers. Instead, Rainbow and Puro.earth overlap in some buyer segments—both serve buyers willing to pay premiums for high-integrity removals—but Puro.earth appeals to risk-averse, long-term-oriented buyers (nonprofits, governments) while Rainbow appeals to EU corporates with CSRD obligations seeking regulatory alignment.
12. Frequently Asked Questions
What does "CCP-eligible" actually mean for buyers?
CCP-eligible means the registry has passed ICVCM's Assessment Framework and meets baseline standards for governance, transparency, and monitoring independence. It's a credibility signal that the registry has been subject to rigorous independent evaluation. However, individual credits are only "CCP-labeled" once the specific methodology under which they were issued is also approved by ICVCM. Rainbow registry-level CCP approval (2025) differs from Rainbow biochar methodology CCP approval (pending Q3-Q4 2026).
Does Rainbow's smaller project portfolio (80 vs. Verra's 2,000+) mean lower credit quality?
No. The narrower scope is intentional—it enables deeper technical expertise and tighter quality controls. Verra's breadth across 20+ methodologies requires generalist approvers. Rainbow's focus on four core pathways allows specialist reviewers. The trade-off is slower project approval and less secondary-market liquidity, not lower quality.
Will Rainbow's biochar methodology approval change credit pricing?
Likely yes—by tightening the premium over Isometric (currently 10-20% above Isometric, 30-50% below Puro.earth). Once methodology approval eliminates "perceived risk" from pending ICVCM assessment, pricing should normalize. The key variable is whether buyers perceive Rainbow's permanence claims as equivalent to already-approved competitors at equal pricing.
Is production-batch crediting better than multi-year fixed periods?
"Better" depends on context. Production-batch improves measurement precision and reduces working capital lockup for developers. For buyers, it creates fine-grained portfolio diversity (many small batches from different facilities/seasons) that reduces concentration risk but increases operational complexity. Multi-year blocks are simpler to manage but create larger tail risks if a single batch proves defective.
Should I wait for Rainbow biochar CCP methodology approval before buying?
Not necessarily. If you believe Rainbow's biochar methodology is scientifically rigorous and the registry governance is solid (both defensible positions), buying before CCP approval lets you capture the pricing discount that will likely disappear post-approval. Conversely, if you're risk-averse on permanence claims pending ICVCM independent assessment, waiting is reasonable.
Can a non-EU project register biochar with Rainbow?
Yes. Rainbow accepts projects globally. However, non-EU projects don't gain the same regulatory credibility signals as EU-based projects (Ministry endorsement, CSRD alignment, EU taxonomy alignment). The economics still work if the project has strong permanence science, but the pricing premium may be smaller for non-EU geography.
How does Rainbow's 2% buffer pool compare to competitors?
Rainbow's 2% biochar buffer aligns with ISO 14064-2 conventions. Isometric runs 2-3%, Verra 3-5%, Puro.earth 5-10%. Lower buffers mean more credits issued per unit of removal (better for developers), but higher permanence risk (worse for buyers). Rainbow's 2% is mid-range—more conservative than Isometric, less extreme than Puro.earth.
13. What Developers & Buyers Should Do Now
For Project Developers
Biochar in France or Northern Europe? Rainbow offers a compelling value proposition: proven methodology, rapid CCP approval expected 2026, and explicit CSRD/EU alignment. The production-batch crediting model rewards continuous improvement—a facility increasing biochar yield sees immediate credit yield improvements, not waiting for fixed baselines. However, be aware that smaller project portfolio (80 vs. Verra's 2,000+) means less liquidity and potentially higher price volatility.
ERW or BiCRS? Opportunity: Rainbow is receptive to novel removal pathways and can approve Tier 2 methodologies faster than legacy registries. Risk: ERW remains in research stage with 40-50% uncertainty discounts. If you're developing ERW, budget for long-term monitoring commitments and accept that near-term credit revenue may be limited. BiCRS developers should monitor ICVCM assessment timeline (late 2026/early 2027) for framework CCP approval.
Choosing between registries? Consider: (1) Geography—EU project? Rainbow's regulatory alignment adds value; (2) Permanence claim—1,000-year (Puro.earth) or 100-year (Rainbow/Isometric)?; (3) Speed to approval—Isometric fastest, Rainbow moderate, Puro.earth slowest; (4) Methodological novelty—novel approach? Rainbow is flexible within CDR-native framework.
For Credit Buyers
CSRD-regulated? Rainbow should be a core procurement partner. CCP eligibility + proven biochar methodology (pending final ICVCM approval) + explicit EU regulatory alignment makes it a natural fit for European corporates credibly claiming carbon removals in sustainability reports without greenwashing risk.
Pricing expectations: Rainbow will likely command 10-20% premium over Isometric (due to specialization and EU positioning) but discount vs. Puro.earth (30-50% premium). Premium should tighten post-ICVCM biochar approval, reducing perceived-risk discount.
Portfolio construction: Multi-registry approach beats single-source risk. Core holdings split between Rainbow (EU-aligned, moderate-permanence) and Isometric (volume, competitive pricing). Smaller Puro.earth reserve hedges extreme permanence tail risks. Monitor Rainbow's production-batch model: fine-grained batch diversity reduces concentration risk but increases operational complexity.
Ready to Explore Rainbow?
Climate Decode helps developers and buyers navigate Rainbow, Isometric, Puro.earth, and the full CCP-eligible durable removals landscape—from methodology selection and crediting strategy to procurement and portfolio construction.
Speak to an Expert →Key Strategic Insight
Rainbow's CCP approval signals that the registry has met institutional scrutiny and is now a legitimate player in the high-integrity removals market. It is not a speculative play on emerging technology; it is a credible, governance-vetted partner. However, it is not a "safe choice" in the sense of maximum liquidity (Verra) or extreme permanence (Puro.earth); it is a smart choice for buyers optimizing for regulatory alignment and methodological specialization.
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