Direct carbon footprint of hydrogen generation via PEM and alkaline electrolysers using various electrical energy sources and considering cell characteristics

Hydrogen supplying to industrial users is currently the major hydrogen business worldwide and the demand for hydrogen is almost entirely supplied from fossil fuels. In the last years a widespread interest on hydrogen has grown as energy vector for the decarbonization of multiple sectors, including industry, transport and buildings. Nevertheless, the impact of natural gas and other fossil fuels substitution with hydrogen is highly affected by the mix of different technologies and energy sources applied for hydrogen generation. The paper aims to investigate current CO2 emissions related with hydrogen generation in Australia and Italy by means of PEM and alkaline technologies; and to evaluate the potential impact considering cell characteristics variation and 3 scenarios based on energy mix. A sensitivity analysis is performed to identify the critical parameters. Based on experimental data, the energy consumption for hydrogen production using PEM technology is more sensitive to cell voltage compared to current density, which indicates the importance of cell manufacturing and electrolyte resistance. In addition, by performing sensitivity analysis regarding energy sources scenarios it is found that carbon dioxide emission in Australia is more sensitive to renewable energy sources rather than Italy.