The Carbon Footprint of Hydrogen Produced with State-of-the-Art Photovoltaic Electricity Using Life-Cycle Assessment Methodology

The production of hydrogen as both chemical feed and energy carrier using low-carbon technologies is one of the solutions to reach net-zero emissions. This paper, firstly, reviews the publications on the life-cycle assessment of photovoltaic (PV)-based hydrogen production focused on the carbon footprint. Secondly, it updates the global warming potential (GWP) values of this H-2 production process considering the state-of-the-art PV panels for installation in Italy. In the literature, H-2 produced in Europe and the rest of the world results in a mean GWP equal to 4.83 and 3.82 kg CO2 eq./kg H-2, respectively, in which PV systems contribute the highest share. The average efficiency of PV panels assumed in the literature is lower than the current PV modules. Updating the supply chain, efficiency, and manufacturing energy and material flows of PV modules can decrease the GWP value of the H-2 produced by nearly 60% (1.75 kg CO2 eq./kg H-2, with use of alkaline electrolyzer) in the Italian context, which can be further reduced with advancements in PV panels or electrolysis efficiency. The study proves that advancement in the PV industry and additional savings in the electrolyzer's electrical demand can further decrease the carbon footprint of PV-based H-2.