The Role of Systems Engineering in Energy Transition – A Framework to Analyze Green Methanol Synthesis in Texas

The new era of energy transition is significantly impacted by technological and economic advances in process technology. It is driven by the need to use renewable energy resources, reducing carbon dioxide, and other greenhouse gas emissions. Electrification has a major role to play in the energy transition, and it can contribute to renewables integration in the current energy mix while also minimizing nonpoint and distributed emissions. However, for hard-to-decarbonize sectors such as refining and chemical manufacturing processes, a dual challenge exists to simultaneously electrify and reduce emissions while supplying the continuous energy required for industrial processes, thereby highlighting the need for wider systems analysis and integration with process technology. The main objective of this work was to design a novel framework for producing green methanol while integrating renewable energy sources into the energy mix. The framework is tested for the viability of a green methanol facility in Texas. Three coastal counties in Texas with five greenhouse gas-emitting facilities were chosen for the case study. Scenarios included incorporating solar photovoltaics (PV) with battery storage, supplementing on-grid and off-grid energy production for electricity generation. Hydrogen required in the methanol production process is supplied through green hydrogen production process, through desalination of seawater, and an integrated system of nanofiltration (NF), reverse osmosis (RO), and membrane brine concentration (MBC) (to avoid coastal brine discharge) is considered. An electrolyzer for producing hydrogen and an electric boiler for providing the required heat to the process are included. The carbon capture unit is designed to accommodate carbon emitted from industrial facilities and power plants at the chosen site. A comprehensive techno-economic analysis (TEA) shows that the production cost for green methanol using the on-grid system is lower than the off-grid system due to cost of batteries. However, life cycle assessment (LCA) demonstrates that adopting an off-grid system produces nearly zero carbon emissions. The internal rate of return (IRR) for the largest methanol production facility in the on-grid case is 32%, while the off-grid case with battery integration is 24%. A sensitivity analysis shows a reduction in production costs through multiple timeline scenarios from 2025 to 2050.