Reverse Water Gas Shift (rWGS). We retrofit the methanol plant by adding an electrification unit that is comprised of an electrolysis unit and of a rWGS unit. The goal of the electrification unit is to obtain the same syngas composition as the SMR unit. The composition of the synthesis gas is adjusted by manipulating the H2/CO2 ratio and reaction temperature. In this work, the reaction temperature is set as 900°C. Because the rWGS reaction is mildly endothermic and the reactor is adiabatic , the feeding stream is preheated to 1078°C (higher than the reaction temperature). After removing water, the product stream is compressed and mixed with synthesis gas produced by SMR. In contrast to the electrolyzer, the rWGS unit is operated under constant production mode, where the feedstock and product streams remain unchanged over time and the reactor runs continuously. The amount of synthesis gas produced by the electrification unit is obtained via optimization. The detailed optimization model is presented in the SI.