How are emissions from existing use or fate (e_exuse) and emissions from fuel in use (e_u) connected? Do they have to be the same?

No. They are separate terms and do not have to be equal.

• e_ex-use = credit for emissions avoided compared with the input’s existing use or fate.

• e_u = emissions from using the final fuel.

• e_p = processing emissions, including CO₂ released as off-gas, venting or leakage.

For RFNBO production using CO₂ as an input, clearly distinguish the credit and burden sides of the CO₂ stream and apply them consistently.

Example: An RFNBO plant receives 100 units of eligible captured CO₂.

If all 100 units are incorporated into e-methanol, the CO₂ may receive an e_ex-use credit and later be accounted for under e_u when the methanol is used.

If only 80 units are incorporated into the fuel and 20 units are released during production, two consistent approaches are possible:

• Full-input approach: credit all 100 units under e_ex-use; account for 80 units under e_u and the 20 units released during processing under e_p.

• Incorporated-fraction approach: credit only the 80 units incorporated into the fuel under e_ex-use; the same 80 units are later accounted for under e_u. The remaining 20 units receive no e_ex-use credit and should not create an additional e_p burden if its release is not additional compared with its existing fate.

In both cases, include upstream emissions from capture, treatment, liquefaction, transport, and handling for the full CO₂ quantity supplied.

The key principle is:

The calculation must be internally consistent: credit CO₂ once, and count any later release once.

This logic applies specifically to RFNBO production using CO₂ as an input and should not automatically be transferred to RCF cases using waste-derived carbon feedstocks.

References: Delegated Regulation (EU) 2023/1185, Annex; ISCC EU 205-1, Sections 3.1.1–3.1.3.