Researchers Develop Technology to Harness Energy from Mixing Freshwater and Seawater

Hyperion Water Reclamation Plant in Los Angeles Image © Doc Searls / Flickr

Salt is power. It might sound like alchemy, but the energy in places where salty ocean water and freshwater mingle could provide a massive source of renewable power. Stanford researchers have developed an affordable, durable technology that could harness this so-called blue energy.

The paper, recently published in American Chemical Society’s ACS Omega, describes the battery and suggests using it to make coastal wastewater treatment plants energy-independent.

“Blue energy is an immense and untapped source of renewable energy,” said study coauthor Kristian Dubrawski, a postdoctoral scholar in civil and environmental engineering at Stanford. “Our battery is a major step toward practically capturing that energy without membranes, moving parts or energy input.”

Dubrawski works in the lab of study co-author Craig Criddle, a professor of civil and environmental engineering known for interdisciplinary field projects of energy-efficient technologies. The idea of developing a battery that taps into salt gradients originated with study coauthors Yi Cui, a professor of materials science and engineering, and Mauro Pasta, a postdoctoral scholar in materials science and engineering at the time of the research. Applying that concept to coastal wastewater treatment plants was Criddle’s twist, born of his long experience developing technologies for wastewater treatment.

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© Rob Jordan/Stanford Woods Institute for the Environment