A study led by SERC Chile researcher and academic at the University of Antofagasta, Dr. Felipe M. Galleguillos Madrid, proposes a new way to produce clean energy from natural salinity contrasts. The research paves the way for the development of blue energy in arid regions, combining science, sustainability, and applied innovation.

The growing global demand for sustainable energy sources has driven the development of new technologies capable of harnessing natural resources available on a continuous basis. In this context, a recent study addresses the most relevant advances in so-called blue energy, generated from the mixing of waters with different salinity levels. 

The work titled “Blue energy recovery in the Atacama Desert via electrochemical ion pumping devices: A Chilean perspective on salinity gradient energy”, led by SERC Chile researcher and academic at the University of Antofagasta, Felipe Galleguillos, presents a comprehensive synthesis of electrochemical energy harvesting systems, with a special focus on Mixing Entropy Batteries (MEBs), membrane-less devices that allow for energy recovery from salinity gradients with high efficiency and lower structural complexity than conventional methods such as pressure-retarded osmosis (PRO) or reverse electrodialysis (RED).

“Blue energy is a type of marine energy, but its recovery can be carried out on the mainland and not directly at sea. The Atacama Desert does not have permanent rivers or estuaries; however, it offers a set of conditions that mimic or exceed the salinity contrasts generated when mixing river water with seawater,” explained the SERC Chile researcher.

Likewise, he mentions that “the operating principle of Mixing Entropy Batteries (MEBs) is based on the recovery of electrical energy from the ionic concentration gradient between two solutions of different salinity, such as fresh water and salt water or industrial brines with atmospheric or municipal water. This type of electrochemical device directly converts the free energy of mixing (mixing entropy) into electricity, taking advantage of reversible ion intercalation reactions in electrode materials typically used in lithium-ion batteries.”

The results of the study showed that systems based on lithium salts (LiCl) achieve high levels of efficiency and stability, maintaining their performance even after multiple operation cycles. Additionally, the team explored alternative materials, such as metal oxides and conductive polymers, which could lower production costs and expand their application in areas with limited water resources.

The study also analyzed new materials, such as metal oxides and conductive polymers, which could make the production of these batteries more efficient and cost-effective. Furthermore, it evaluated their performance in environments with high salt concentrations, such as industrial effluents or brines from mining and desalination processes. This approach would allow for the utilization of resources currently considered waste, integrating blue energy into solar systems within a circular economy and off-grid generation model.

The study proposes a critical framework for advancing towards the scalability and practical application of these technologies, opening a new line of research and offering a significant set of opportunities for arid regions such as the Atacama Desert. “In this territory, where water scarcity and the high energy demand of mining are constant challenges, the possibility of generating energy from the salinity difference between seawater and waste brines from desalination plants represents a renewable and clean alternative that could reduce electrical consumption and associated emissions.”

“In the salt flats, these technologies could also be applied to recover energy during the extraction of lithium and other minerals, promoting a circular economy around water and energy use. Given the vast solar radiation in the Atacama, combining solar energy with salinity gradients would further enhance regional energy self-sufficiency, favoring the sustainability of coastal communities, industrial plants, and mining operations,” he added.

Finally, he indicated that “this technology would not only contribute to the water and energy security of northern Chile but would also position the region as a hub for scientific and technological innovation in clean energies.”