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

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 powerto-
methanol process combining CO2 capture, water/CO2 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.