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

The growing global demand for sustainable energy sources has driven the development of new technologies capable of harnessing continuously available natural resources. In this context, a recent study examines the most significant advances in so-called “blue energy,” which is generated from a mixture of water with varying levels of salinity. 

The study titled “Blue Energy Harvesting in the Atacama Desert Using Electrochemical Ion-Pumping Devices: A Chilean Perspective on Salinity Gradient Energy, ” led by Felipe Galleguillos, a researcher at SERC Chile and professor at the University of Antofagasta, presents a comprehensive overview of electrochemical energy-harvesting systems, with a special focus on Mixing Entropy Batteries (MEBs), membrane-free devices that enable the recovery of energy from salinity gradients with high efficiency and less structural complexity than conventional methods such as pressure-retarded osmosis (PRO) or reverse electrodialysis (RED).

“Blue energy is a type of marine energy, but it can be harvested on land rather than directly at sea. The Atacama Desert has no permanent rivers or estuaries; however, it offers a set of conditions that match or exceed the salinity contrasts created when river water mixes with seawater,” explained the researcher from SERC Chile.

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

The study's results showed that lithium salt (LiCl)-based systems achieve high levels of efficiency and stability, maintaining their performance even after multiple operating cycles. In addition, the team explored alternative materials, such as metal oxides and conductive polymers, that could lower production costs and expand their use in areas with limited water resources.

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

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

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

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