Blog Post

The Mass Balance Chain of Custody model

The mass balance approach is primarily associated with tracking the flow of materials through a series of processes or across different stages of the supply chain, often used in the context of sustainable material sourcing or recycling.

This method allocates the input of mixed materials (such as recycled and non-recycled content) across the output products in proportion to their mass. The exact mass of sustainable material must be certified and tracked along the supply chain and reconciled to reflect the ratio of sustainable material integrated into the final product. This serves to back up sustainability claims such as, “made with 90% recycled plastic” although customers have no way of knowing if the final product actually contains any molecules of the sustainable materials or not.

This approach is most common for products and commodities where segregation is very difficult or impossible to achieve, such as in the plastics and petrochemical industry, but also utilised in other segments like transport and metals supply chains. Principles of mass balance can be indirectly relevant to GHG accounting in specific contexts, such as:

Recycled and Recyclable Materials

In scenarios where the use of recycled materials influences the GHG emissions associated with a product or process, considering the reduced impact of using recycled versus virgin materials.

Scope 3 Emissions

For companies calculating their value chain (Scope 3) emissions, especially when assessing emissions associated with purchased goods and services, fuel used in transport and end-of-life treatment of sold products.

The mass balance approach might inform the allocation of emissions in complex supply chains. CarbonLeap makes tracking, tracing, compliance and verification of the mass balance principle possible through identification of inputs and outputs, quantitative analysis, process optimization, sustainability measurements, supply chain coordination and technology integration. This process is supported by its Carbon Bank using state of the art digital technology powered by SAP.

Terms To Remember


The concept of "additionality" in the context of greenhouse gas (GHG) protocols and carbon accounting is an important but sometimes complex topic, often described in terms of what would occur without a specific project or policy intervention. It revolves around the idea of distinguishing between GHG reductions that result directly from a specific intervention and those that would have happened anyway, without it.

The GHG Protocol for Project Accounting, developed through a collaborative process by the World Resources Institute (WRI) and the World Business Council for Sustainable Development (WBCSD), provides a comprehensive framework for quantifying and reporting GHG reductions from mitigation projects. Additionality plays a crucial role in carbon insetting by ensuring that the carbon reduction efforts within a company's own supply chain (Scope 3) are genuinely additional and wouldn't have occurred without the specific insetting intervention.

This concept is vital to qualify for insetting certification and to ensure the integrity and credibility of these efforts. It requires external financing and a careful assessment to confirm that the emission reductions are indeed above and beyond what would have occurred under a business-as-usual scenario.

CarbonLeap takes specific measures to make sure that additionality is imbedded in all its transactions. For instance, in transport decarbonization it takes into consideration all cost elements of the intervention (the fuel switch) including government subsidies to determine abatement cost and viability of the deal.

No double counting and double claiming

This is distinct from co-claiming and co-paying which is what incentivizes contributions throughout the value chain for accommodating the CO2 reduction interventions. To avoid double claiming and double counting in carbon insetting, it's essential to establish clear protocols for tracing, validating, and reporting carbon reductions. This involves ensuring that emission reductions are uniquely accounted for and attributed, thereby preventing any overlap in claims between different entities within the value chain.

Transparent, third-party validation and adherence to standards and certifications help safeguard against these risks, ensuring that each emission reduction is only counted and claimed once, aligning with broader sustainability and regulatory requirements. CarbonLeap’s CarbonBank powered by SAP using blockchain technology furthermore enhances the immutability of the Impact Units.


In the context of carbon insetting, causality refers to the direct impact that insetting actions have on carbon emission reductions within a company's supply chain. It emphasizes the need for clear, measurable outcomes that can be directly linked to specific insetting interventions, ensuring that the efforts truly contribute to overall emissions reduction goals and are not just incidental or unrelated outcomes.