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

By Muhammad Nizami, Widodo Wahyu Purwanto

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.