Marianna Basoulou

The continuous increase in Renewable Energy Sources (RES) in Greece’s electricity system has led to growing energy curtailment due to limited grid capacity, especially in high-production regions. According to recent data, more than 200 GWh of clean energy was curtailed in a single quarter in 2024, highlighting the urgent need for effective storage solutions. Curtailment represents a growing system level challenge, but it also creates an opportunity to convert surplus renewable electricity into green hydrogen through electrolysis. This study quantifies the hydrogen production potential of curtailed RES electricity in four Greek regions, Peloponnese, Crete, Thrace, and Western Macedonia, and evaluates alternative storage pathways under harmonized techno-economic assumptions. A scenario-based framework is developed using regional RES capacity, curtailment estimates, electrolyzer efficiency, hydrogen conversion factors, and indicative storage cost ranges. The analysis compares pressurized tank storage, underground storage, and hybrid configurations, while also estimating avoided CO₂ emissions from the substitution of grey hydrogen. The results indicate substantial regional variation. The Peloponnese exhibits the highest annual hydrogen potential, followed by Crete, Thrace, and Western Macedonia, while each region presents different infrastructure constraints and deployment roles. Mainland regions with access to geological storage show lower indicative hydrogen costs than island systems, where storage and export constraints increase costs. The findings show that curtailed renewable electricity can function as a low-carbon feedstock for hydrogen production in Greece, supporting grid flexibility, regional decarbonization, and the gradual development of hydrogen hubs under differentiated regional strategies.

Air pollution is a global environmental issue that primarily affects the health of city residents. The purpose of this study was to comprehensively assess air pollution levels in the center of Athens and compare them with those in the peri urban Mt. Hymettus Aesthetic Forest. To achieve this, two low-cost sensors, namely, the “PurpleAir PA-II-SD,” were combined with the employed methodology. The first sensor was stationed at a fixed central point in the Mt. Hymettus Aesthetic Forest, whereas the second one captured measurements along a specific route among six points in the historic center of Athens during the summer of 2021. The pollutants measured included PM₁₀, PM_2.5, and PM₁, as well as temperature and humidity. The research findings indicated that all pollutant values were significantly higher in the center of Athens, particularly in terms of PM_2.5, which exceeded the permissible limits set by the European Commission. Furthermore, notable variations in temperature were observed in both areas.