Closing the Carbon Cycle: Challenges and Opportunities of CO2 Electrolyser Designs in Light of Cross-Industrial CO2 Source-Sink Matching in the European Landscape

The defossilisation of the chemical industry is a critical milestone in achieving climate-friendly and sustainable production routes. In this regard, CO2-electrolysis technologies have emerged as a foundational element of Carbon Capture and Utilisation (CCU) technologies, facilitating the valorisation of CO2-emissions as a source of valuable synthons. However, there are still fundamental questions that must be addressed. These include identifying the most promising CO2 point sources, determining the maturity level of the different reactor designs, and identifying which target product has the highest drop-in market potential. The objective of this study is to establish a comprehensive carbon source-sink roadmap for today and in the future (i.e. 2050), with a particular emphasis on the European context. In this article, we integrate the current and projected demand for products and building blocks derived from CO2-electrolysis and CO2-emissions from industrial sectors with inherent CO2-emissions. Additionally, we explore the role of direct air capture in the future. Strengthened by a statistical analysis of over 5000 publications relating to CO2-electroreduction covering both low- and high-temperature electrolysis for three different product classes (CO, formic acid as well as ethylene/ethanol) conclusions on the most probable employment scenarios for each technology are drawn. We believe that this analysis will serve to stimulate discourse and the establishment of CO2-to-X value chains among academic and industrial collaborators, while concurrently furnishing the community with a roadmap of the requisite issues that must be addressed, promoting finally better data reporting and standardisation of metrics.