THUNDER aims to develop an innovative, modular solution for e-MeOH production, addressing high costs, energy demand, and inefficiencies of benchmark. Using a one-pot tandem approach, the solution combines three reactions: (1) CO2 and H2O vapor capture, (2) co-electrolysis to produce CO and green H2, and (3) CO2/CO hydrogenation to synthesize e-MeOH. THUNDER will enhance efficiency with multifunctional membranes for CO2 capture, advanced electrocatalysts for CO and H2 production, and thermochemical catalysts for hydrogenating CO2 and CO into e-MeOH. Using renewable energy and recovering surplus heat, THUNDER will reduce energy consumption compared to benchmark. THUNDER modular design reduces infrastructure costs, optimizes material use, and minimizes reliance on critical raw materials. THUNDER’s impact on process efficiency, cost, sustainability, and renewable energy will be evaluated along the project. 5. It’s expected to be a reduction in green house emission of 75%, 50-60% in CAPEX and 8-16% in OPEX. Additionally, by recycling CO2/H2O vapor and residual heat from fuel cells, THUNDER facilitates e-MeOH production for fuel cell energy generation, effectively closing the carbon loop and optimizing overall resource and energy efficiency. Key outputs include: (i) advanced materials such as catalysts, membranes, and 3D-printed reactors from recycled titanium, (ii) process intensification, integrating all steps into a unified system, (iii) technology optimization from TRL3 to TRL4 through testing with real and simulated flue gases, and (iv) validation of e-MeOH in fuel cells for mobility and electricity applications. In summary, THUNDER will play a pivotal role in the transition to a sustainable economy, fostering modular, efficient and cost-competitive production of carbon-neutral synthetic fuels production from renewable energies.