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'Blue energy' could be another way to go green
February 13, 2017

A simple way to produce a lot of energy could be found anywhere a river meets the sea.

Researchers call it “blue energy,” and it could be the next frontier in clean-energy technology.

Osmosis occurs when salty water hits freshwater across a permeable membrane. Salt ions (molecules with an electrical charge) will pass through the membrane until the amount of salt is equal on both sides.

“Making use of the osmotic pressure difference between freshwater and seawater is an attractive, renewable and clean way to generate power,” explain researchers at École Polytechnique Fédérale de Lausanne (EPFL) in Lausanne, Switzerland, who collaborated with researchers at the University of Illinois.

The researchers wondered if they could figure out how to capture that electrical charge as it moved across the membrane separating the fresh and salty water. They did it by creating two tiny membranes, just three atoms thick, made of molybdenum disulfide, which is plentiful and easy to produce. Then they made a tiny hole in the membranes and let osmosis take over and push the electrically charged salt ions through this tiny hole, called a nanopore.

EPFL’s research is part of a growing trend. Scientists around the world have been developing systems that leverage “osmotic power” to create electricity. Projects are underway in Norway, the Netherlands, Japan and the United States, the science news site Phys.org reported.

This article draws on a report from the Voice of America.