Scientists have long predicted that wet areas of the world will get wetter in a warming climate, even as the dry ones get drier. Climate change is already happening all around us, with seasons shifting all over the calendar, and severe weather becoming far too common.
As we continue to pollute and destroy ecosystems, it’s likely that temperature fluctuations will continue, becoming too warm and/or wet for comfort in many circumstances. But humans, along with every other species, will have to adapt or die. Scientists working on new sources of energy generation say that in the future, a hotter, wetter world could actually be a blessing in disguise.
According to Ozgur Sahin, Ph.D., water evaporation is a huge and untapped power source already at work in nature. Sahin recently published results of research conducted at the Wyss Institute of Biologically Inspired Engineering at Harvard University. Those results suggest that bacterial spores could be used to harness the untapped power of evaporating water, creating a new way of generating green electricity.
Evaporation is happening all around us all the time, as an essential part of the Earth’s water cycle. According to the U.S. Geological Survey, studies have shown that the oceans, seas, lakes and rivers provide nearly 90 percent of the moisture in the atmosphere via evaporation, with the remaining 10 percent being contributed by plant transpiration. This water vapor rises up from the ocean, eventually settling as snow on the world’s highest peaks. It was this amazing, yet often overlooked show of strength that inspired Sahin to think about humidity and evaporation as a source of energy.
Up until now, that energy has been Mother Nature’s secret, but Sahin is working to break the code so that humans can also harness this power. In the future, Sahin believes that electrical generators could be driven by changes in humidity from sun-warmed ponds and harbors.
Here’s how it works: A sheet of rubber is coated on one side with spores. When the environment is dry, the spores shrivel like raisins do in the sun. The action causes the rubber to bend, much as a pine cone opens as it dries or a freshly fallen leaf curls. The incredible thing about the spores is that the shriveling is only temporary. When the environment becomes more humid, they regain their original shape, moving the rubber sheet back into its original position.
While these might seem like very subtle changes, Sahin claims this action of bending back and forth means the spore-coated sheets can can be harvested to generate electricity. ”Simply increasing the humidity from that of a dry, sunny day to a humid, misty one enabled the flexible, spore-coated plank to generate 1000 times as much force as human muscle, and at least 10 times as much as other materials engineers currently use to build actuators, he discovered. In fact, moistening a pound of dry spores would generate enough force to lift a car one meter off the ground.”
Since solar and wind energy production can fluctuate dramatically with the weather, and storage systems aren’t yet robust enough to support the grid, some experts believe humidity power could be a much-needed compliment.
“If changes in humidity could be harnessed to generate electricity night and day using a scaled up version of this new generator, it could provide the world with a desperately needed new source of renewable energy,” said Wyss Institute Founding Director Don Ingber, M.D., Ph.D.
Image via US Geological Survey