Solar PV based power-to-methanol via direct CO2 hydrogenation and H2O electrolysis: Techno-economic and environmental assessment

Abstract

Renewable-power-assisted CO2 capture and utilization (CCU) for methanol synthesis has gained significant attention. This study assesses the techno-enviro-economics of methanol synthesis via CO2 hydrogenation using renewable hydrogen from photovoltaic (PV)-based electrolysis and CO2 originating from natural gas field processing. The study was performed under two scenarios: PV electrolysis with a battery and without a battery, using grid electricity. The proposed process system was simulated using Aspen HYSYS v11. A proton exchange membrane (PEM) electrolyzer was chosen for electrolysis. Methanol synthesis via CO2 hydrogenation was modeled using kinetic models by considering both CO and CO2 as carbon sources. An economic analysis using a levelized cost process and an environmental assessment of CO2-eq emissions were performed. The results show that the overall energy efficiency of integrated hydrogen production and methanol synthesis before and after the heat integration process using a heat exchanger network (HEN) were 48.39% and 55.16%, respectively. From an economic perspective, the methanol production cost was 1040.17 and 1669.56 $/tonne-MeOH for the PV–grid and PV–battery scenarios, respectively. From an environmental perspective, the CO2-eq emissions from the whole process were 0.244 and − 0.016 kg-CO2-eq/MJ-MeOH for the PV–grid and PV–battery scenarios, respectively.