We make our own billets and roll them in the same plant. Do we count the billets as a precursor?

Question

Senseible · Accepted Answer

You can either treat billet making and rolling as one production process, or keep them separate and pass the billets' figure into rolling as a precursor. Either works if each tonne of CO2 is counted once. The usual error is adding the billet emissions twice: once as direct emissions and again as a precursor. Combined: one production process covering melting and rolling; direct emissions of both, divided by tonnes of rolled product. Separate: billets get their own figure; rolling adds its fuel plus billets consumed times that figure. If you also sell billets, you need their own figure anyway, and separating keeps rolled products from carrying melting emissions for billets that were sold. Total CO2 attributed across all products should not exceed the installation's direct emissions plus bought precursors. If it does, something is counted twice.

We make our own billets and roll them in the same plant. Do we count the billets as a precursor?

Two ways to set it up

When separate is better

Check for double counting

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