How to choose a carbon registry

A carbon registry is a digital platform that records carbon credits from approved projects once they have been verified. It tracks when credits are issued, traded, and retired, helping to prevent double counting. In essence, it functions as the accounting system of the carbon market.

One carbon credit is equivalent to one tonne of verified carbon reduction or removal. Individuals or companies generally buy these credits to offset their GHG (greenhouse gas) emissions that would, for example, be produced further down their supply chain and otherwise contribute to climate change.

Although there are certainly others, the four main carbon registries we have focused this article on are:

- Puro.earth

- Verra

- Gold Standard

- Isometric

Different carbon registries have differing methodologies for project developers to adhere to, with clear instructions on what type of information needs to be provided for a project to be approved and carbon credits to be issued. These are regularly reviewed and updated according to the latest research and as the industry evolves. Ultimately though, how do you choose a carbon registry?

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1) What kind of project are you developing?

Are you involved with a CDR (Carbon Dioxide Removal) project or something broader that includes avoidance or carbon reduction? If it is CDR projects you are engaged in, Puro.earth and Isometric are better suited as they are both exclusively CDR-focused platforms with methodologies that ensure durable carbon removal credits are issued. If avoidance or reductions in carbon are your organization's main focus, both Verra and Gold Standard cover these projects.  

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2) Type of Project Pathway

The type of tech pathway that your project takes must also be factored in when deciding on a carbon registry. Puro.earth is generally best suited for engineered carbon removal projects as they provide expert guidance on pyrolysis/gasification and other industrial projects, with over 50 biochar projects under their wing.  

Verra is good for broader avoidance and large-scale projects. Their main strengths lie in projects involving utility renewables or industrial pollutants, with specialized methods for forestry and energy intensive sectors.  

Isometric is best suited for high-rigor, durable removal projects. Although the newest of the four main carbon registries, Isometric focuses on high quality, durable carbon removal projects like biomass storage, biochar, and other tech enabled pathways. This platform is overall best suited for science-based startups in CDR or ERW (Enhanced Rock Weathering).

Gold Standard is mainly suited for projects that have major social/environmental co-benefits. The main strengths of the Gold Standard platform are that they excel in community-based projects that are small to medium size in scale, and they have discounts for projects in developing countries. This platform is best suited for NGO’s or companies prioritizing impacts outside of the standard climate-based benefits of carbon projects.

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3) Permanence and Durability

The permanence of carbon credits refers to whether the benefit of the carbon removal project is maintained over time, or reversed by changes like system failure, forest fires, or changes in land use. Permanence is estimated by conducting risk assessments of the carbon project, whereby the higher the risk rating, the lower the permanence of the carbon credit.

The durability of carbon credits refers to how long the carbon is expected to be stored by the carbon removal project before it is released back into the atmosphere, expressed in years. The durability of a carbon credit is estimated by a series of methodology-specific calculations that account for real-world examples, scientific research and physical models.

Puro.earth categorizes the carbon removal projects by different tiers of permanence and durability. These are as follows:

• CORC100+: Credits expected to keep carbon out of the atmosphere for at least 100 years. The type of projects that fall under this category are typically biochar projects, terrestrial biomass storage projects, engineered subsurface biomass storage projects, etc.  

• CORC200+: Credits are expected to keep carbon stored away from the atmosphere for at least 200 years. At present this category is still being populated, and several methodologies are being considered, but it is still active in its transition stages.  

• CORC1000+: Long term credits expected to keep carbon stored for 1000’s of years. Projects involving DAC (Direct Air Capture), geological storage, and ERW fall under this category. This is the highest durability tier including engineered/ geological storage projects where it’s very unlikely that the carbon returns to the atmosphere.

Isometric generally requires carbon projects to demonstrate a storage durability of at least 1000 years. While 1000 years is the benchmark, certain projects like biochar can be eligible for a 200-year durability credit, depending on the measured carbon stability of the biochar.

Verra does not have fixed durability tiers, instead this platform prioritizes long-term carbon storage which is quantified using permanence risk assessments, monitoring, buffer pools, and scientific research. For any nature-based projects, extra credits are set aside to account for future reversals.  

Gold Standard, much like Verra also does not have fixed durability thresholds, instead they quantify permanence and durability of the credits using a mx of scientific research, rigorous monitoring methods, buffer pools and permanence risk assessments. Projects are required to show adequate proof that their carbon credits are eligible, long-term, additional, and have safeguards in place in case of reversal.

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4) Scientific Rigor and MRV

MRV (Monitoring, Reporting, Verification) is the foundational framework used in carbon markets to ensure all GHG emissions related to the projects are monitored and any carbon removals, reductions or avoidances are verified. MRV is the foundation of trust between carbon credit buyers and sellers and, without it, any carbon credits produced could be overstated, double-counted, or meaningless. In turn, this could lead to scandals, greenwashing accusations and, overall, not making a positive impact on the climate.  

Out of all the carbon registries, Verra and Gold Standard require the most supporting documentation to be provided for MRV. This includes project design documentation, baselines, proof of additionality, monitoring plans, periodic reports, leakage assessments, third party verification, etc.

Puro.earth requires moderate levels of documentation to be submitted prior to verification, but most of it has been streamlined with the introduction of their own dMRV (digital Measuring, Reporting, Verification) platform that makes it easier for suppliers and project developers to submit their data.

Isometric requires the least amount of traditional supporting documentation out of the discussed registries as the platform does not rely on long narrative verification reports. Instead, data is submitted for review digitally, which is also open to the public for consultation.

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5) Accreditations

All of the mentioned registries are CCP (Core Carbon Principles) eligible, set up by the ICVCM (Integrity Council for the Voluntary Carbon Market). This means that all the discussed registries meet the recognized baseline for credibility, quality, and integrity in the voluntary carbon market.  

In addition, Puro.earth is also endorsed by ICROA (International Carbon Reduction and Offset Alliance) which is a key quality marker for offsets.

Verra and Gold Standard, in addition to CPP, also aligns with CORSIA (Carbon Offsetting and Reduction Scheme for International Aviation) meaning it is considered suitable by airlines to offset their emissions from international flights.

Isometric is the first carbon registry to be endorsed by both ICROA (conditionally) and CORSIA. This highlights that, although the newest entrant, they have a high scientific rigor and level of transparency.

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6) Pricing and Fees

When starting a biochar project to generate carbon credits, all four registries have different charges and standards to get your project reviewed, approved, and publicly listed. These are separate to per credit fees or costs to audit the project.  

The main fees associated with listing projects on Puro.earth, Verra and Gold Standard are below:

Isometric has zero upfront costs for suppliers, and all verification and certification fees are charged directly to buyers and not the project developers. This platform is extremely supplier-friendly, ideal if you are a project developer. The average upfront cost is $0.

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7) Buyer Appeal

Puro.earth has the highest buyer appeal due to the proven liquidity of the credits and the high transparency on the platform in terms of public price indexes and project data.  Additionally, the scale and track record of the platform is a big draw, with over 100 facilities based in multiple countries. Puro.earth is also extremely reliable as they have had offtakes from major corporations such as Microsoft, Nasdaq etc.

Gold Standard is a more niche registry, but there is buyer appeal due to the strong focus on project co-benefits. Gold Standard requires you to deliver strong social and environmental impacts, so buyers with an ESG focus prefer this platform.

Isometric, although quite new, is rising fast in terms of buyer appeal. More quality-conscious buyers prefer this platform as it is the first registry to be CPP-labeled. They also have a focus on science driven protocols, digital MRV and have fully transparent project listings. The buyer-funded platform also ensures minimal conflicts with suppliers and appeals to those wanting rigor when it comes to purchasing credits. They have also had major deals with some big names; Google, Anglo American etc., adding a layer of reliability to this platform.

Verra has, at times, faced comparatively lower buyer appeal due to scrutiny of certain projects and concerns about overstated impacts. However, as one of the largest and most established carbon standards, Verra continues to play a central role in the voluntary carbon market and has taken steps to strengthen its methodologies and oversight in response to stakeholder feedback.

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8) Technology

Isometric is explicitly AI-native with verification, validation of data analysis, quantification and all other MRV processes done via AI. This makes the process of issuing credits more efficient and rigorous, making Isometric the leading tech/AI disruptor in terms of registries for speed and transparency.

Puro.earth, Verra, and Gold Standard have also recently introduced dMRV programs which are all in different stages of development and approval. But these platforms are still largely methodology driven rather than AI first.

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9) Communication

All four of the discussed registries use updates via their websites, communicated via email and social media, as their main mode of communication to make suppliers and buyers aware of news, methodology updates etc. However, between the four, the volume and structure of communication varies.

Verra leads in terms of the frequency and structure of their news and releases as they tend to be more common and broad, whereas Isometric has an iterative and public heavy mode of communication. Puro.earth has a more targeted and efficient mode of communication which is more practical for suppliers and Gold Standard communicates their updates less frequently but tends to be more impact oriented.

While all four registries maintain a good level of transparency, Isometric and Verra stand out for being the most inclusive and proactive platforms in terms of communication.

Summary

There is no one-size-fits-all carbon registry for project developers. Different registries serve different pathways to suit a range of project scales, long term goals, risk tolerances, methodologies, finances and reporting constraints.

For early-stage startups, Isometric provides a $0 startup cost, is more buyer-funded, has structured dMRV to make data submission easier and rigorous, and would not require lengthy report-writing, whilst making their requirements clearer upfront.

For companies looking to develop durable carbon removal projects (such as DAC, ERW or BECCS), Isometric or Puro.earth are the best suited carbon registries as they make durability expectations clear and provide detailed methodologies on how to get carbon credits via these types of projects approved and verified. For developers with nature-based or mixed portfolios, Verra or Gold Standard are best suited as they have more experience in broader, large-scale projects.

Choosing a carbon registry is one of the most important decisions that a carbon project developer will make. This effectively shapes how a project will be perceived in the carbon market, the standards the projects will follow over time, how effectively climate goals will be met, and how a project will expand. A carbon registry is the credibility signal of a project developer, dictating the operations framework and long-term trajectory of the company. Picking the correct one must ultimately be based on the companies' goals, ambitions, and maturity.