Carbon Yield
In this context, we use carbon yield (also often referred to as carbon return) to describe the total amount of carbon dioxide equivalent (CO₂e) that a project successfully removes from the atmosphere and stores in vegetation or soil. It indicates the contribution the project makes towards reducing climate change and forms the basis for generating carbon credits.
To provide a comparable measure of carbon capture, carbon yield is calculated per hectare over a defined period. It is typically measured as above and below ground woody biomass plus debris, approximately 50% of which is carbon accumulated per unit area and can be expressed in terms of tonnes of carbon dioxide equivalent per hectare per year ( tCO₂e / ha / yr).
For this assessment, carbon yield is based on the 25-year crediting period used by the Clean Energy Regulator.
How efficiently carbon is captured as part of carbon offset projects and reforestation efforts depends on factors like:
- Plant species (fast-growing trees vs. slow-growing vegetation)
- Growth rate and biomass accumulation
- Soil quality and environmental conditions
- Carbon allocation in roots, stems, and leaves
Estimated carbon return
Gross carbon return is the total carbon captured, while net carbon return (in ACCUs) is what remains after accounting for Regulatory deductions for Risk of Reversal (5% for 25 & 100 year projects) and Risk of Permanence (20% for 25 year projects) and deductions of project emissions if applicable.
Gross
Your Project Total gross return is calculated over the projects’ lifetime, which for sequestration projects is based on a 25-year crediting period (i.e. you model ACCU return and will receive ACCUs for only 25 years even with 100 year permanence projects).
The crediting period is the timeframe during which a project is eligible to earn and claim carbon credits (e.g., Australian Carbon Credit Units or ACCUs). Crediting periods vary depending on project type and methodology.
Your projects permanence period will always extend beyond your crediting period as your permanence period only begins when you first get issued ACCUs.
Net
Your Project Total net return is calculated on the basis of a set permanence period. The permanence period (25 or 100 years) applies specifically to sequestration projects and is the period for which the carbon stocks must be retained to ensure the long-term effectiveness of the project.
For projects with a 25 or 100 year permanence period, the Risk of Reversal buffer reduces the ACCUs issued during a reporting period by 5%.
For projects with a 25-year permanence period, a 20% permanence discount also applies.
A risk of reversal buffer protects the ACCU Scheme against potential loss of carbon and other risks that can't be managed by other permanence obligations.
For more information on Permanence obligations and the Risk of Reversal buffer, please visit the CER website.