Optimal production of green hydrogen with grid assistance for enhanced flexibility

The use of grid power to compensate for shortages of renewable energy results in higher profit at electrolysis facilities. However, the carbon footprint of hydrogen increases in regions where fossil sources have a significant share in the energy mix. This contribution seeks to balance profit with carbon footprint through mathematical programming. The case study comprises a 100-MWp wind power plant, and data on electricity price and CO2-emissions content in the grid, covering a full-year of operation in northern Germany. The results show that the highest profit is attained at maximum load, with a minor influence of the electricity price (<75 €/MWh) and no influence of the CO2-emissions content of the grid. In this scenario, approximately 50% of the power stems from conventional sources. Therefore, a cost penalty is proposed to the use of fossil power to limit the grid assistance. This further reduces the grid contribution to around 30%, still allowing for a high profit.