Co-processing is defined as the simultaneous processing of a base feedstock (typically fossil crude oil) with a biogenic feedstock (bio-oils, such as vegetable oils, used cooking oil, pyrolysis oil, etc.). Co-processing is typically performed in a petroleum refinery setup, but can also occur in other types of installations.
The benefit of co-processing is that fossil feedstock can (incrementally) be replaced with renewables. This introduces a certain renewables share into the product slate of the co-processing facility, while achieving the same product quality as an installation operating solely on the base feedstock. To determine the resulting share of renewables in each product of the facility, several different calculation methods can be used. These methods may potentially lead to different outcomes. Therefore, the European Commission published a Delegated Regulation to the Renewable Energy Directive (RED) to set out clearly defined rules (see PDF here) on the calculation of the resulting renewables share for products obtained via co-processing facilities. It should be noted that all RED-compliant biofuels are eligible for co-processing under this regulation.
The regulation was processed via the Better Regulation portal of the European Commission (open in new tab).