Industry Insight | ISCC PLUS Mass-Balance Guidance Goes Operational: What It Means for Tire Pyrolysis
On 22 September 2026, ISCC formally released version 1.1 of its ISCC PLUS Mass Balance Guidance. Pyrolysis consultancy Weibold has published an analysis of what it means for end-of-life tire (ELT) pyrolysis. Below we summarize the key points and share Enrestec’s view.
What changes
- Chemical connectivity: an output receiving sustainability characteristics must have a demonstrated chemical link to the certified input.
- Tighter attribution from 2027: from 1 January 2027, Free Attribution must reflect the characteristics of the inputs. Inputs that compensate for each other must be similar in nature, with the economic values of certified and non-certified inputs within a factor of five (the consultation draft proposed ten).
- Site level, real data: mass balance is managed at site level, credits cannot exceed actual output, and calculations must include losses and rely on actual operating data.
- Separate bookkeeping per process: where processes are clearly distinguished and separately recorded, different mass-balance approaches may be used within one certified site — for example, for recovered carbon black (rCB) and tyre pyrolysis oil (TPO).
- Fuel vs. material use: the guidance introduces Fuel-Use Excluded Attribution to distinguish outputs intended for fuel or energy use from non-fuel material outputs, with further details to follow in later versions.
- ISCC EU and ISCC PLUS are not interchangeable: ISCC EU connects to regulatory pathways such as the EU Renewable Energy Directive, while ISCC PLUS serves voluntary circular and bio-based supply chains; each quantity can be accounted for only once.
Our view
1. Certification becomes part of plant design, not just paperwork. When calculations must use actual operating data and include losses, a stable, measurable process is the starting point. Enrestec’s continuous pyrolysis runs 24/7 at over 90% uptime with consistent crude carbon black and oil yields, so inputs, outputs and losses can be fully recorded — the foundation of a credible mass balance.
2. Separate bookkeeping for rCB and TPO favours integrated plants. rCB is a material product, while TPO may go to fuel or to chemical feedstock. Process-level bookkeeping combined with the fuel/material distinction lets operators design a certification path for each product according to where it goes, and makes the value of TPO as a chemical-recycling feedstock clearer.
3. New plants should design their certification architecture up front. Where to place metering points, how to trace material and how to keep records are best settled during Front-End Engineering Design (FEED), not added after construction — one reason we recommend that equipment customers start with FEED.
4. Buyers will look at the certification architecture itself. When tire makers and chemical companies assess recycled feedstock, they will ask which ISCC scheme applies, which mass-balance approach is used and whether chemical connectivity can be shown, alongside quality. Enrestec holds ISCC PLUS certification, and our subsidiary Upcycle was certified to ISCC PLUS in March 2026, both with full traceability from feedstock intake to shipment. Enrestec is also in the process of obtaining ISCC EU certification, so that our tyre pyrolysis oil (TPO) can also connect to regulatory pathways under EU rules. We will keep following future versions of the guidance to help customers source verifiable circular materials.
Source: Weibold — ISCC PLUS gets operational: what the new mass-balance guidance means for ELT pyrolysis (29 September 2026). This article is Enrestec’s summary and opinion; the official ISCC documents prevail.