Key Concepts

Carbon Pools — What you need to know

Once a project's carbon credits have been tokenized and fractionalized using the Carbon Bridge, these credits are represented as TCO2 tokens (Toucan carbon tonnes). A TCO2 token contract still contains all the project-specific attributes, such as the project's country or methodology. This means tokens from one project are not interchangeable with tokens from another project, even if they are very similar.

Pool logic

Each pool has a unique configuration and carries a certain logic that dictates which TCO2 tokens can be deposited into it. This logic is based on two filters:
  1. 1.
    Is the token to be deposited a TCO2 Toucan carbon token?
    This check guarantees that only whitelisted token contracts are accepted and prevents somebody from depositing a custom token into a carbon pool.
  2. 2.
    Do the TCO2 token attributes satisfy the pool's requirements?
    When a pool is deployed, it needs to specify gating attributes. Any TCO2 token deposited in the pool must contain at least these attributes — otherwise the deposit transaction will revent.
A few examples of gating attributes a carbon pool might have:
  • type = removal — a pool that only accepts carbon removal credits.
  • vintage = >2015 — only accepts credits from 2016 and later.
  • country = Colombia — only accepts TCO2s from Colombia.
For example, we could create a carbon removal pool, with a token called CRT (carbon removal tonne). This specific pool would only carry one defining attribute: type = removal. In this case, the carbon removal pool token could be called CRT.
Of course, pools could also use a combination of gating attributes, meaning we can create liquid carbon pool tokens backed by pools of similar tokenized credits.


For now, the Toucan team has worked with collaborators at KlimaDAO to deploy the first carbon pool, the Base Carbon Tonne (BCT). The gating attributes for the Base Carbon Tonne pool: TCO2 tokens must be Verra VCUs, and they must have a vintage of 2008 or greater.
Soon we will publish a post detailing our path to decentralization, where we will describe our plan to make the creation of these pools completely permissionless in the future. This will empower market actors to create curated carbon pools, and for the market to decide which attributes are seen as key differentiators.