Scaling and performance assessment of power-to-methane system based on an operation scenario

Abstract

In this study, scaling and performance assessment of a power-to-methane (PtM) system based on a new operation strategy is presented. The strategy is principally based on avoidance of hydrogen storage, selection of appropriate hydrogen content of product gas (mainly consisting of CO2, H2, and CH4), and catalyst loading in the reactor. In this regard, a zero-dimensional (0-D) mathematical model is developed for the CO2 methanation fixed bed reactor and the photovoltaic (PV) panels, while the alkaline electrolyzer is described based on an available polarization curve. The model developed for the reactor is then compared with the experimental study found in the literature. Simulation environment is created for a small scale PtM system based on arbitrary CO2 supply profile and solar irradiance data for one year. Based on this data, the main system components are sized. For example, three solar PV panels with the size of 2 m2 each can be sufficient to drive a 600 kW PtM system in September, while a system with two additional solar PV panels is required to drive a 900 kW PtM system in February. The system’s electrical efficiency is found between 55 and 59 % under variable operating conditions.