One of the more important technical questions running through the current Greenhouse Gas Protocol (GHG Protocol) and ISO - International Organization for Standardization standard revision process is how chain of custody models should determine the integrity of a corporate or product-level emissions claim.
It's a question that anyone working with product certifications like ISCC PLUS (ISCC – the International Sustainability and Carbon Certification) already lives with day to day.
Five models sit along a spectrum from full physical traceability to complete decoupling of the certified attribute from the physical product:
Identity Preservation maintains a single certified source, physically separated at every stage. Maximum integrity, maximum operational complexity.
Segregation allows multiple certified sources to be combined, but keeps certified and non-certified streams physically apart. The attribute is preserved; the specific origin is not.
Controlled Blending mixes certified and non-certified inputs in a fixed ratio, so every unit of output contains a known, guaranteed proportion of the certified material.
Mass Balance permits mixing without physical separation. Certified attributes are allocated proportionally across outputs at the system level over a defined period (i.e. credible in aggregate, but not traceable to individual units).
Book and Claim separates the attribute entirely from the physical product. Certificates are issued and traded independently, with no required connection between who holds the credit and who receives the material.
For companies operating across multiple assets, product lines, and markets (i.e. each with different feedstock mixes, energy sources, and certification requirements) keeping this clear across the business is genuinely difficult. ClimateTab (A Three Pillars Consulting Product) is built for exactly this complexity.
Companies can construct GHG inventories at the product level across all of their assets and operations, maintaining clear separation between products with different attributes, specifications, and certification statuses.
As chain of custody requirements become more formally embedded in GHG reporting standards, having that product-level transparency built into your accounting infrastructure (rather than reconstructed after the fact) is what makes credible claims possible.
