A new type of electrical generator uses bacterial spores to harness the untapped power of evaporating water, according to research conducted at the Wyss Institute of Biologically Inspired Engineering at Harvard University. Its developers foresee electrical generators driven by changes in humidity from sun-warmed ponds and harbors.
The prototype generators work by harnessing the movement of a sheet of rubber coated on one side with spores. The sheet bends when it dries out, much as a pine cone opens as it dries or a freshly fallen leaf curls, and then straightens when humidity rises. Such bending back and forth means that spore-coated sheets or tiny planks can act as actuators that drive movement, and that movement can be harvested to generate electricity.
Also: Learn about a Phase Change Material Thermal Power Generator.