The aim of this project is to develop and model an integrated modular system based on continuous-flow heterogeneous photo(electro)catalytic reactors to produce relevant chemicals such as ethylene in the chemical sector, precursor to "green plastics" and many other high-value chemicals using abundant resources such as water, carbon dioxide and light. We aim at delivering cost-efficient small-scale systems for intermittent operation to respond to the needs of rural, isolated territories, and distributed manufacturing. Novel multifunctional photo(electro)catalytic materials integrated into practical and scalable reactors are required in Europe to maintain the technological leadership in chemical manufacturing, while ensuring the deployment of sustainable processes which meet circular economy and green industry for a low-carbon future. FlowPhotoChem will use the expertise of the partners to design, model, construct and validate an integrated modular system with improved energy efficiency and negative CO2 emissions, since concentrated CO2 will be valorised to high-value chemicals. The integrated system will be studied from a life cycle analysis perspective to quantify such effects, and to include a techno-economic study to quantify the cost of the technology and compare with comparable renewable solutions for the production of the same/similar chemicals.