Slovak Republic
Estimation of the Potential for Green Hydrogen Production from Untapped Renewable Energy Sources in Spain in 2024
Nov 2025
Publication
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 18419 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 280999 t (PEM) to 320897 t (AEL) with AEM yielding an intermediate value of 307247 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.
Flashback Behavior and Safety Implications of Hydrogen-natural Gas Mixtures
Nov 2025
Publication
Hydrogen blending in natural gas systems is a key transitional strategy for reducing carbon emissions. This study explores the influence of hydrogen on combustion properties including flame flashback risk quenching distance and energy efficiency. Experimental and computational analyses demonstrate that hydrogen addition increases flame speed but reduces calorific value and quenching distance thereby impacting combustion stability and safety. Findings suggest that optimizing burner design and combustion control strategies is essential for safely and efficiently using hydrogen-enriched natural gas. Experimental validation confirmed that a 1.50 mm channel dimension effectively prevented flame flashback for hydrogen concentrations up to 40% in natural gas. As energy systems evolve toward decarbonization this research provides critical insights into the feasibility and challenges of hydrogen integration in residential or industrial applications. The study investigated the combustion behavior of natural gas enriched with various concentrations of hydrogen (up to 25%). Dynamic or fluctuating mixing conditions were excluded as the implementation of such a system in energy sector applications would necessitate a stable and well-defined gas composition.
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