Feasibility assessment of power-to-methanol through solar thermochemical hydrogen production plant: A case study

Abstract

Power-to-X technologies are pivotal in the future energy landscape, converting renewable electricity into valuable chemicals and fuels. This study proposes a novel solar-based methanol production system to decarbonize an existing power plant through a case study. The system integrates a copper-chlorine (Cu-Cl) thermochemical water-splitting cycle as a promising technology for sustainable hydrogen production with an oxy-fuel combined cycle power plant to determine if it can create e-methanol at a lower cost than alternative methanol production technologies. The power-to-methanol (PtM) system is modeled to establish its technical framework. Subsequently, hourly dynamic simulations are performed, and the effect of real-world solar conditions on the annual system performance is investigated, considering meteorological data. It is demonstrated that the system can produce hydrogen and methanol at competitive production costs while featuring lower operating expenses (OPEX) due to lower electricity consumption than conventional electrolysis methods. Moreover, the surplus electricity produced from the integrated gas turbine and steam Rankine cycles can be sold to the grid and increase the economic performance of the proposed PtM system. The considered system operates optimally at the design direct normal irradiance (DNI) of 881 W/m². Under these conditions, the cost of hydrogen and e-methanol is about $5.5/kg and $1,531/tonne. The CO₂ emissions analysis also reveals that the proposed system utilizes 32 % of the annually captured CO₂ (1.3 kgCO₂/kgMeOH). With analysts projecting the carbon price to increase to around $186/tCO₂ by 2035, the levelized cost of methanol (LCOM) would decrease to $1,291/tonne, enhancing the cost-competitiveness of e-methanol production.