The salt of the earth (oceans and rivers, too)

Sometimes, I read about a scientific breakthrough and if it isn’t too complicated and if it is explained relatively clearly, I say to myself: “Yeah, I can see how that might work.” When I first heard about smoother peanut butter that wouldn’t stick to the roof of your mouth, I nodded affirmatively. I could appreciate the deep thinking that went into that one. Here’s another example: Putting omega-3, cholesterol-fighting oil into eggs, that high-cholesterol, albeit high-protein food. Now, that was smart.

 

But a new study in our ACS journal Nano Letters takes smart to a new level. This one makes me say to myself: “How on earth did they come up with this ingenious idea?” And I’m pretty confident you’ll have the same reaction after you read this…

 

Scientists are reporting development of a new battery that extracts and stores energy produced from the difference in saltiness at the point where freshwater in rivers flows into oceans. This battery could supply about 13 percent of the world’s energy needs, the researchers estimate.

 

So am I right or am I right?

Yi Cui and colleagues cite the intensive global scientific effort to develop renewable energy sources to supplement supplies of oil and other traditional fuels like coal, which contribute to global warming. Solar, wind, and geothermal are renewable, sustainable energy sources that have attracted much attention recently. Scientists long have known about the possibility of producing electricity from differences in the salinity, or saltiness, of water. So the new study focused on development of more practical ways of tapping that potential.

The result was a so-called “mixing entropy battery.” Alternating the flow of river water and sea water through the battery produces electricity to charge it. The process also can be reversed to remove salt from ocean water to produce drinking water. The scientists describe the battery a very promising potential addition to the ranks of solar, wind, and other renewable energy, and are working on modifications to make the device a commercial reality. For more information, go to salty battery.

 

Photo: Wikimedia Commons.