times the number of variables should suffice. In the present study, a sampling size 20 times the number of variables has been applied, which has been used with good experience previously by the author. The sampling plan and recorded simulation model output is used to train a Kriging model using the pyKriging package. See also for other examples and more information about Kriging in chemical engineering applications. Surrogate models are built for various simulation / techno-economic output: LCOM, CAPEX, OPEX, Power requirement, Methanol production. The validated surrogate models are used to estimate process parameters and operating conditions for optimal green methanol production.