Estimation of the Potential for Green Hydrogen Production from Untapped Renewable Energy Sources in Spain in 2024

The increasing integration of renewable energy sources (RES) in Spain is leading to substantial amounts of surplus electricity, presenting a strategic opportunity for green hydrogen production as a key enabler of energy storage and decarbonisation. This study quantifies this untapped potential for 2024. Based on the difference between installed renewable capacity and actual generation, an economically viable surplus of 18,419 GWh was identified within an optimal 10-h operating window. The hydrogen production potential was modelled for three electrolysis technologies—Alkaline (AEL), Proton Exchange Membrane (PEM) and Anion Exchange Membrane (AEM)—using total energy consumption values of 57.40, 65.55 and 59.95 MWh/t H2, respectively, including auxiliary systems. The estimated annual hydrogen production ranges from 280,999 t (PEM) to 320,897 t (AEL), with AEM yielding an intermediate value of 307,247 t. The analysis reveals a strong regional concentration, with more than 63% of the potential located in Castile and León, Andalusia, Castile-La Mancha and Extremadura. While this range represents an upper technical limit, it highlights the significant opportunity to valorise surplus renewable energy, contingent on targeted investment and a supportive regulatory framework.