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- Identification of saline areas in wetlands using spectral indices and geochemical data. The case of Baixo Vouga Lagunar (Aveiro, Portugal)Publication . Rolo, R. S. V.; Silva, S. M. L.; Medina, Jorge; Patinha, CarlaABSTRACT: The Baixo Vouga Lagoon (BVL) is an important wetland on the Portuguese coastal continent that has been suffering from the destruction of its agricultural fields due to saline intrusion processes. The aim of the research was to identify areas of salinity combining geochemical data and spectral indices obtained from Sentinel 2B satellite images. The methodology was developed using images from July 2023 and February 2024, with samples taken during the same seasonal period. Fourteen spectral indices were calculated: four vegetation indices and ten salinity indices. Pearson's method was used to assess the correlation between geochemical data and the spectral indices. The Canopy Response Salinity Index (CRSI) and Salinity Index 1 (SI 1) showed the highest correlation, at 0.428 and 0.516 respectively. Despite the limitations of using optical sensor in flooded areas, the spectral response of halophyte vegetation in areas of higher salinity was crucial for its differentiation and primary delimitation of the most affected areas.
- Unit Sizing and Feasibility Analysis of Green Hydrogen Storage Utilizing Excess Energy for Energy IslandsPublication . Koca, Kemal; Dursun, Erkan; Bekçi, Eyüp; Uçar, Suat; AKPOLAT, Alper Nabi; Tsami, Maria; Simões, Teresa; Tesch, Luana; AKSÖZ, Ahmet; Borg, Ruben PaulABSTRACT: This study examines whether green hydrogen production using combined wind and solar energy on Marmara Island can meet the island's electricity demand and fuel the fuel needs of a hydrogen-powered ferry. A hybrid system consisting of a 10 MW wind farm, a 3 MW solar PV system, and a PEM electrolyzer sized to meet the island's hydrogen demand was modeled for the island, located in the southwestern Sea of Marmara. The hydrogen production potential, energy flows, and techno-economic performance were evaluated using HOMER-Pro 3.18.4 version. According to the simulation results, the hybrid system generates approximately 62.6 GWh of electricity annually, achieving an 82.8% renewable energy share. A significant portion of the produced energy is transferred to the electrolyzer, producing approximately 729 tons of green hydrogen annually. The economic analysis demonstrates that the system is financially viable, with a net present cost of USD 61.53 million and a levelized energy cost of USD 0.175/kWh. Additionally, the design has the potential to reduce approximately 2637 tons of CO2 emissions over a 25-year period. The results demonstrate that integrating renewable energy sources with hydrogen production can provide a cost-effective and low-carbon solution for isolated communities such as islands, strengthening energy independence and supporting sustainable transportation options. It has been demonstrated that hydrogen produced by PEM electrolyzers powered by excess energy from the hybrid system could provide a reliable fuel source for hydrogen-fueled ferries operating between Marmara Island and the mainland. Overall, the findings indicate that pairing renewable energy generation with hydrogen production offers a realistic pathway for islands seeking cleaner transportation options and greater energy independence.