Advances in reverse electrodialysis for renewable energy generation

Salinity gradient energy, also known as Blue Energy, is the energy released from the mixing of two solutions with different salinity, such as seawater and river water. It is a renewable and sustainable energy source that integrates the hydrological cycle, having an important role in the transition to renewable and clean energy, without CO2 emissions. Reverse electrodialysis is the electro-membrane process used in this thesis to harvest the salinity gradient energy. In reverse electrodialysis, the concentration gradient across ion exchange membranes results in a potential difference over each membrane that can be collected. This thesis focuses on the trade-off between power density and energy efficiency harvesting, including the optimization of both parameters, and enhancing the process’ sustainability. Accordingly, the research aims to understand how electrode segmentation and multistage operation, using scaled-up stacks with artificial and natural seawater and river water can improve the obtained power density and energy efficiency, and aims to evaluate carbon-based slurries’ performance to replace the redox solution at the electrodes. The outcomes presented in this thesis result from both modelling, developed in Python, and experimental work. The experimental work was developed at the laboratory using artificial waters and at a pilot scale using natural waters at the Afsluitdijk, the Netherlands.