When it Comes to Traceability Methods for SAF, Book & Claim leads the Way
Aviation contributes approximately 2-3% of global CO₂ emissions annually, a figure projected to grow as air travel demand rises. Sustainable aviation fuel (SAF) offers a promising pathway to decarbonization, with the potential to reduce lifecycle emissions by up to 80% compared to conventional jet fuel. But verifying SAF’s sustainability requires robust systems to track and confirm the fuel’s environmental attributes from production to use, from well to wake.
The challenge? Aviation operates on a global scale with complex supply chains and shared infrastructure. And, without book & claim, the fuel can cross borders multiple times before reaching aircraft. While there are a few different traceability methodologies, book & claim stands out as the optimal solution for aviation’s unique needs. Let’s dig into why.
Understanding Traceability Methods
There are four main traceability methodologies: mass balance, book & claim, segregation, and identity preservation. These methodologies differ in how they handle environmental attributes throughout the supply chain. Here’s how the four main approaches compare:
Mass Balance
This accounting-based method allows sustainable and conventional materials to be mixed while also proportionally allocating the environmental attributes based on the inputs. For example, if 30% of the feedstock used to produce a batch of SAF was sustainable, 30% of the resulting SAF can be certified as sustainable, even when it’s physically comingled with non-sustainable product.
- Strengths: Cost-effective for complex supply chains where the attributes need to maintain a theoretical link with the physical commodity. Scalable for bulk commodities like corn, soybeans, and wheat
- Limitations: No guarantee that any specific batch of end product is physically sustainable. Requires strict monitoring and auditing to prevent over-allocation and maintain integrity
Book & Claim
With book & claim, the fuel’s environmental attributes are separated from the physical product and sold separately as environmental attribute certificates (EACs). SAF producers generate certificates equal to the fuel’s emissions reductions, which buyers can purchase and claim for compliance, regardless of where the physical fuel is used.
- Strengths: Highly flexible. Connects producers in low-demand regions to buyers globally. Accelerates market growth by opening the market to Scope 3 customers
- Limitations: Depends on certificate integrity and whether or not the claim needs to be linked to the physical product. Market volatility can incentivize specific traceability mechanisms over others
Segregation
With the segregation method, sustainable materials remain physically separated throughout the entire supply chain, ensuring no mixing with conventional fuels.
- Strengths: High certainty of physical sustainability
- Limitations: Requires expensive, dedicated storage and transport infrastructure
Identity Preservation
Identity preservation is the most stringent approach and is similar to tracking organic produce from farm to table. This method maintains complete chain-of-custody, from feedstock production to fueling a plane, with unique identifiers for each batch.
- Strengths: Maximum traceability and verification
- Limitations: Extremely high costs. Impractical for large-scale commodities like SAF
Both segregation and identity preservation require segregated storage and transport, which is economically unfeasible for aviation’s volumes.
Methods at Work in Aviation
Hard-to-abate sectors, like aviation, present unique decarbonization challenges. Not only is SAF in short supply, it’s often produced far from where it’s used. However, shipping SAF around the world increases cost, logistics, and emissions. On top of that, all jet fuel is chemically identical, which makes physical tracking complex. This is why using an efficient, effective, and trusted traceability method is so critical. Currently, mass balance and book & claim are the two most widely used methods.
Mass Balance in Aviation: A common approach in the petroleum world, this is currently the most common approach for SAF blending. Mass balance works well for domestic markets but faces verification challenges when fuel crosses borders and attributes dilute across international supply chains.
Book & Claim in Aviation: One of the biggest benefits of book & claim is that it eliminates the need for the delivery of physical fuel and enables companies anywhere to benefit from SAF, regardless of where the fuel is physically produced or delivered. This opens the door for leading companies to address their transportation and cargo emissions efficiently, effectively, and innovatively.
For example, a European airline could purchase SAF certificates (SAFc) from a U.S. SAF producer and claim reductions for flights anywhere in their network. Unfortunately, some regulations, like the EU’s Renewable Energy Directive, require the mass balance methodology for member states to claim reductions. However, some of the world’s leading companies are currently using book & claim to reduce their Scope 3 air travel and transport emissions, helping to grow demand for SAF.
Why International Aviation Demands a Different Approach
International aviation faces unique obstacles that amplify traceability challenges:
- Regulatory Fragmentation: Standards vary dramatically across regions. The EU mandates SAF blending targets with strict chain-of-custody requirements, while the U.S. offers tax credits. The International Civil Aviation Organization’s (ICAO) Carbon Offsetting and Reduction Scheme for International Aviation (CORSIA) provides a global scheme but cannot be stacked with regional SAF mandates. This patchwork creates risks of double-counting or credits failing to be recognized across jurisdictions.
- Supply Chain Complexity: With traditional traceability methods, fuel can repeatedly cross borders, and emissions often happen in international airspace outside any single nation’s control. This makes physical tracking impractical. It also makes it incredibly difficult for corporations working to decarbonize their Scope 3 emissions to take action.
- Economic Barriers: Rigid methodologies like segregation and identity preservation require significant infrastructure investments, which could deter SAF production in developing regions. This exacerbates global inequities, with wealthier markets reaping the benefits.
- The Nature of Greenhouse Gases: Unlike localized pollutants, the impact of CO₂ is atmospheric and borderless. That means emissions saved anywhere are emissions saved everywhere. A ton of CO₂ avoided in Brazil delivers the same climate benefit as one avoided in the United States.
The Case for Book & Claim
Book & claim is the most efficient, cost-effective traceability methodology for aviation. The ability to separate environmental attributes from a physical fuel removes fundamental barriers that otherwise put supply-chain decarbonization out of reach for most companies. Here’s how:
- Overcoming Logistics: With book & claim, the physical SAF doesn’t need to be delivered to specific airports or airlines. This helps avoid infrastructure upgrades estimated to cost billions, while also reducing the logistical burden and transport emissions of moving fuel across countries and continents.
- Market Efficiency: Book & claim enables producers in remote areas to monetize the environmental attributes of their SAF, stimulating global supply and creating economic opportunities in underserved markets. Book & claim also expands the SAF market because it enables any business, in any sector and in any location, to reduce its aviation-related emissions.
- Scalability: Book & claim supports aviation’s growth without steep increases in traceability costs. Industry models suggest book & claim could triple SAF adoption rates compared to mass balance approaches.
- Addressing Risks: To prevent greenwashing and maintain market integrity, robust systems like digital ledgers and transparent registries are essential. Organizations like the Roundtable on Sustainable Biomaterials (RSB) have developed frameworks specifically for certifying and managing environmental attributes in book & claim systems.
The Path Forward
Traceability is vital for SAF’s credibility, but aviation’s global scope demands innovation beyond traditional supply chain models. While mass balance offers practicality for regional markets and segregation provides physical assurance for niche applications, book & claim’s attribute-based approach is helping to grow the SAF industry by driving innovation, reducing logistics and cost, and building confidence in the market.
As the aviation industry works toward net-zero by 2050, book & claim provides the flexibility and scalability needed to accelerate SAF adoption globally, connecting producers and buyers across borders while delivering verified, measurable climate benefits wherever aircraft fly.
