In plain English
Accelerated Carbonation of Concrete Aggregate
Accelerated Carbonation of Concrete Aggregate is a removal method run by Gold Standard. People often refer to it by its code, GS-CSACA. It works in the industry space.
In short
Mineralising CO₂ into recycled concrete aggregate for durable storage.
What it is
This Gold Standard methodology covers technology-based carbon removal through accelerated carbonation of demolished concrete, known as concrete aggregate. Concrete aggregate is exposed to an increased carbon dioxide concentration so the gas reacts with calcium compounds in the cement phase and forms stable carbonate minerals, permanently storing the carbon dioxide. Eligible activities use either direct or indirect mineral carbonation at concrete recycling facilities before the aggregate enters downstream uses. Each credit represents one tonne of carbon dioxide permanently sequestered.
What it rewards
The reward is a credit called a Verified Emission Reduction (VER). One credit stands for one tonne of carbon dioxide kept out of the atmosphere (or taken back out of it). One tonne of CO₂-equivalent verified-and-issued. A whole period of work is issued as one batch of credits at a time, in the same way a registry issues a batch.
What gets measured
To earn VER credits, a project has to measure and prove a few things. An independent reviewer checks the evidence before any credits are issued.
The baseline: what would most likely have happened to the land or the emissions if the project had not gone ahead.
The activity data for the period, with clear units and a clear source for every number.
The net result actually achieved, checked by an independent reviewer before any credits are issued.
Who takes part
Standard Registry. Owns the policy, approves participants, anchors each issuance to its evidence.
Project Proponent. Registers the project and submits monitoring reports.
Validation & Verification Body. Independently validates the design and verifies monitored data.
How it works
- 1
The project team registers the project and its plan.
- 2
An independent reviewer checks that the plan is sound and that the benefit is real and would not have happened anyway.
- 3
The team looks after the site and measures the agreed indicators over time.
- 4
The independent reviewer verifies those measurements.
- 5
Credits are issued for the verified result, and a buyer can retire a credit to claim the benefit once.
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