Decarbonizing European refineries: GHG accounting framework and potential assessment for co-processed biofuels

Co-processing of biogenic feedstocks in existing crude oil refineries is a promising, near-term option to decarbonize transport fuels by using existing fossil conversion infrastructure. This study quantifies the life cycle greenhouse gas (GHG) emissions of co-processed biofuels under an average European refinery configuration, using a policy-compliant approach consistent with the EU Renewable Energy Directive (RED), which has been integrated with a refinery-wide mass and energy balance model. Four case studies were selected: used cooking oil (UCO) co-processing in hydrotreating (HT) and hydrocracking (HC) conversion routes, and fast pyrolysis oil (FPO) and stabilized/hydrotreated pyrolysis oil (SPO/HDO) co-processing in fluid catalytic cracking (FCC) conversion pathways. Biogenic feed shares of 5–20 wt% at the conversion unit inlet were modelled, together with a full mass and energy balance for all pathways, derived to develop a comprehensive LCI for each pathway. Considered products comprised biogenic diesel, biogenic gasoline and biogenic kerosene. All pathways achieved substantial GHG savings relative to fossil fuels, with carbon intensities ranging from 3.9 to 25.8 g CO 2 e MJ −1 and GHG emissions savings of 73–96 %, thus remaining well above the 65 % RED minimum GHG emissions reduction threshold. UCO hydroprocessing delivered the lowest carbon intensities, while FCC pathways showed higher values, due to lower liquid-fuel yields and greater upstream burdens. Extrapolating the representative case-study yields to the entire EU refining system, a theoretical biofuel potential of up to 13.9 Mt y −1 at 5 % bio-share at conversion unit inlet is estimated.