RSM approach for stochastic sensitivity analysis of the economicsustainability of a methanol production plant using renewable energy sources

This study aims at investigating the economic viability, at the pre-feasibility level, of a 5 MW electrolyserbase-methanol production plant, coupled with a PV power plant. The Authors investigated the impact ofdifferent parameters, such as the PV plant size, the electrical energy cost and the components capitalcosts on the methanol production cost and on the system economic viability. It was also analyzed theminimum recommended sale price of the methanol in order to assure an adequate time frame for thereturn of the investment, considering a different combination of the investigated parameters.An economic sensitivity analysis, based on the RSM approach, was performed in order to define themost promising economic conditions under which the plant can be considered a profitable investment interms of ARR. A guide for an economically viable plant design, allowing for the identification of the mostsuitable combination of the economic parameters, was proposed as a kind of“maps of existence”. For thereference case, the Methanol Production Cost (MPC) resulted around 324V/ton and the minimummethanol sale price to achieve a PBP of 10 years. The sensitivity analysis identified the cost of electricityand the capital cost of the electrolyser as the most affecting parameters for the system economic viability.In terms of ARR, the methanol price represents the most significant factor. Considering a methanol saleprice ranging between 400 and 1200eur/ton, the ARR varied from 5% (20 year of PBP) to 20% (5years ofPBP). From the environmental point of view, it is worth underling that the methanol production planthere proposed allows to recycle about 5800 tons of CO2per year and to avoid the consumption of about5.2 MNm3of NG per year (compared to the traditional production).