Here is a bit more information on the process:

When evaporation energy is scaled up, the researchers predict, it could one day produce electricity from giant floating power generators that sit on bays or reservoirs, or from huge rotating machines akin to wind turbines that sit above water, said Ozgur Sahin, Ph.D., an associate professor of biological sciences and physics at Columbia University and the paper’s lead author.

“Evaporation is a fundamental force of nature,” Sahin said. “It’s everywhere, and it’s more powerful than other forces like wind and waves.”

Last year, Sahin found that when bacterial spores shrink and swell with changing humidity, they can push and pull other objects forcefully. They pack more energy, pound for pound, than other materials used in engineering for moving objects, he reported in a paper published in Nature Nanotechnology, which was based on work Sahin had started as a Scholar in Residence at the Wyss Institute for Biologically Inspired Engineering at Harvard University.

We hope this works and emerges as an efficient and cost effective energy medium!

thanks to Science Daily for the great write-up