Design and Evaluation of a High-Density Energy Storage Route with CO2 Re-Use, Water Electrolysis and Methanol Synthesis

Abstract The energy transition corresponding to more electricity generation from variable and decentralized renewable energy sources requires the development of electricity storage technologies ranging from seconds to seasons. The power-to-fuel process provides a way to store electricity as a liquid energy vector, leading to high energy density and cheap long-term storage at ambient conditions. In the present work, we study the power-to-methanol process combining CO 2 capture, water/CO 2 co-electrolysis and methanol synthesis. An Aspen Plus model focussing on the electrolysis and methanol synthesis sub-processes is presented. The energy conversion efficiency is improved from 40.1 to 53.0 % thanks to heat integration using the pinch method. Further works include the experimental demonstration of this technology as well as the development of control strategies for its regulation.