Dual-objective optimization of photovoltaic and electrolyzer size ratios for hydrogen production: economic and carbon emissions perspectives

Hydrogen is a zero-emissions fuel that, if generated from renewable energy sources, can play a vital role in reducing carbon emissions across multiple sectors. Green hydrogen production plants are constrained by the availability of renewable sources and there is not a common sizing criterion to couple water electrolyzers with renewable technologies. This study aims at filling the research gap involving the preliminary sizing of water electrolyzers to be coupled with photovoltaic systems according to different objectives and final production targets. The problem was formulated and addressed using a MILP optimization algorithm in MATLAB and solved according to the minimum costs and minimum carbon emissions criteria. Additionally, the optimization algorithm was run on three different final demand scenarios: hydrogen production from stand-alone plant, production to meet hydrogen final demand, and production to meet hydrogen and electricity final demands. Results show that the optimal ratio is between about 1.8 and 2 in the cases with cost minimization, but it increases up to 5.75 when both costs and carbon emissions are taken into account.