Collecting CBAM data from suppliers: building a system that works

Collecting your own installation data is an engineering problem; collecting your supplier’s data is a commercial relationship problem. Most CBAM programmes stall at the second step, because you have no enforcement power — only contracts and alternative suppliers.

Define exactly what you need

Asking a supplier to “send your carbon footprint” does not work; what comes back is usually a number lifted from a corporate sustainability report that cannot be attributed to a product. What you need is specific: embedded emissions per tonne for a given CN code, from a given installation, for a given reporting period, split into direct and indirect.

• Installation identity and location — which plant supplied the goods can vary by product
• Production route — the same good made by different routes has different emissions
• Reporting period — which calendar year the data covers
• Direct and indirect emissions reported separately
• The electricity emission factor used, and its source
• Emissions of their own precursors — where the chain continues upstream
• Verification status: verified or not, by whom, in what scope

Put it in the contract

Goodwill-based data collection collapses during the first busy period. Adding an emissions data clause to supply contracts is the only durable way to manage that risk. The clause should settle three things: what data, in what format, by what date. It should also oblige the supplier to make the data verifiable and to share supporting records if the verifier asks.

It is easy to add to new contracts; in existing relationships the annual price negotiation is the natural opening. The most effective argument is to quantify the cost: show that a non-reporting supplier’s product is more expensive for your importer.

Use a template, refuse free-form

Data arriving from twenty suppliers in twenty formats cannot be consolidated. Define a single data template with mandatory unit, scope and period fields. The template also teaches the supplier what is expected — most suppliers are not unwilling, they simply do not know which number to send.

Classify supplier maturity

Chasing every supplier with equal intensity wastes resources. Classify suppliers on two axes: contribution to total embedded emissions, and current data maturity. High-contribution, low-maturity suppliers are the urgent group; for low-contribution suppliers, using a default value is a rational choice.

This is the same logic as hotspot analysis on the LCA side: concentrate effort where it changes the result. Once a hotspot map exists, both the CBAM and the EPD data collection plans use the same prioritisation.