Climate change is one of the greatest challenges of our time. Under the auspices of the UN Framework Convention on Climate Change and through the Paris Agreement, there is a commitment to keep global temperature rise this century to well below two degrees Celsius compared with pre-industrial levels. This will require a variety of strategies, including increased renewable power generation, broad-scale electrification, greater energy efficiency, and carbon-negative technologies. With increasing support worldwide, innovations in carbon capture and utilization (CCU) technologies are now widely acknowledged to contribute to achieving climate mitigation targets while creating economic opportunities. To assess the environmental impacts and commercial competitiveness of these innovations, consistent and transparent Life Cycle Assessment (LCA) and Techno-Economic Assessment (TEA) are needed. Against this background, guidelines (Version 1.0) on LCA and TEA were published in 2018 and updated (Version 1.1) in 2020 as a valuable toolkit for evaluating and guiding CCU technology development. Ever since, an open community of practitioners, commissioners, and users of such assessments has been involved in gathering feedback on the document. That feedback has informed the improvements and the expansion incorporated in Version 2.0 of the Guidelines. This revised and expanded version 2.0 of the Guidelines has again been developed by a team of researchers at RWTH Aachen, TU Berlin, the Institute for Advanced Sustainability Studies Potsdam, the University of Sheffield, and the University of Michigan. Several workshops, the work of the International CCU Assessment Harmonization Group, and feedback from practitioners and users of LCA and TEA studies, have contributed to this updated version. Version 2.0 includes new chapters on integrated assessments that combine LCA and TEA, how to assess early-stage technologies, and how to include social impact in LCA and TEA.