Climate change is real. Energy transition plays a crucial role in addressing climate change where solar fuels have emerged as a critical player in reducing the dependence on fossil fuels in industries that cannot transition into renewable electricity as an energy source such as aviation, industrial feedstocks etc. Green methanol is a promising solar fuel if it is sourced via carbon capture technologies. This thesis aims to build and use a model of an integrated methanol synthesis microplant as a tool to predict methanol production and the performance of the microplant under multiple system architectures at Zero Emission Fuels B.V (ZEF) who are developing a solar powered green methanol synthesis plant. The research commenced with data preprocessing which utilised historical weather data from the C3S database. Subsequently, individual subsystem models were developed such as solar photovoltaic (PV) modules, direct air capture (DAC), fluid machinery (FM), alkaline electrolysis cell (AEC), methanol synthesis (MS), distillation (DS), buffer tanks, and battery system. To ensure the microplant's functionality, a sophisticated control algorithm was devised, operating on two distinct levels: battery management and power distribution. Moreover, diverse microplant architectures were designed, to address unique operational scenarios and environmental conditions. The investigation further explored the influence of temporal granularity, and component sizing on microplant behavior. Ultimately, this thesis establishes the feasibility of the ZEF microplant, offering valuable insights for practical implementation across multiple locations. Consequently, it underscores the potential of the ZEF microplant as a promising solution in the transition towards sustainable energy alternatives.