This study developed an integrated method to identify deployment pathways for greenhouse gas emissions reductions in an industrial plant. The approach distinguishes itself by assessing the techno-economic performance of combinations of mitigation options at the level of core processes of an industrial plant. Thus, synergies between mitigation options like economies of scale and negative interactions, such as overlap in emission reduction potential, are incorporated, resulting in more realistic insights into costs and associated risks. The method was successfully applied to a large petroleum refinery (similar to 4.1 MtCO(2)/y) in northwest Europe. The studied mitigation routes are: energy efficiency measures, carbon capture and storage, fast pyrolysis of woody biomass to produce infrastructure-ready transportation fuels, and gasification of torrefied wood pellets to produce electricity, hydrogen and/or Fischer-Tropsch fuels. Four deployment pathways were examined, all starting with energy efficiency measures and followed by (1) oxyfuel combustion capture, (2) post-combustion capture, (3) biomass gasification, or (4) biomass gasification with carbon capture and storage. Pathway 4 is most cost-effective under medium assumptions, regardless of the emissions reduction target, and allows for deep emissions reductions (6.3 MtCO(2)-eq/y; 154% reduction compared to the 2012 base case). For a 75% emissions reduction target, the average avoidance cost of pathway 4 is around -25 is an element of(2012)/tCO(2)-eq. In comparison, the second most cost-effective pathway (1) was evaluated at average avoidance cost of -5 is an element of(2012)/tCO(2).eq. However, the ranking of the pathways in terms of avoidance cost depends heavily on future energy prices.