This report describes a methodology developed to aid modelling the inventory data for the C4U CASOH and DISPLACE capture technologies, at high TRL for a prospective life cycle assessment (LCA). The methodology includes the modelling of process changes, scaling, and synergies as well as industrial learning and external development.  Expert inputs is used to obtain a robust and realistic inventory, specifically in relation to (1) the changes in process integration due to transition to high TRL, (2) the electricity and heat consumption, (3) the utilities flows, and (4) the main materials used for the production of the equipment.