Tiny Generator Powered by Sunlight and Motion

Take a thin-film solar cell embedded with dye-coated zinc oxide nanowires. Put it on a slice of silicon.

On the other side of the slice, add a nanoscale generator that uses zinc oxide nanowires to turn any kind of motion into electricity. This generator produces electricity using the same principle that a record player uses to convert vibrations in a vinyl LP's groove into electrical impulses.

The result is a tool that harvests energy from sunlight or motion.

Such a tool was recently devised by researchers from the Georgia Institute of Technology, or Georgia Tech as it is affectionately called.

Since the generator can make electricity from any kind of movement -- including biological -- it would thrive near a throbbing environment like a jet engine. Sure enough, according to Zhong Lin Wang, the inventor of the nanoscale generator, these devices would likely be used first in military aircraft brimming with sensors.

Down the road, nanogenerators could eliminate the need for batteries in implantable medical sensors. They would create electricity from simple human motion such as walking, typing or the rise and fall of a person's chest with every breath.

Bioelectricity Beats Biofuel in Efficiency

Burning plants to produce electricity is a more efficient way to power cars than turning those plants into biofuels.

That's the conclusion reached by a study conducted by a team from the University of California at Merced and reported in the journal Science.

In fact, the bioelectricity from an acre of crop would propel a car 81% farther than the ethanol produced from the same acre. The bioelectricity would power an electric car, of course, while the ethanol would turn an internal combustion engine.

Electric powertrains are more efficient than internal combustion engines, giving biolectricity an inherent edge over ethanol.

Another advantage of using bioelectricity: Unlike the ethanol conversion process, bioelectricity generation produces no greenhouse gases. The carbon released during combustion is the same carbon that the plant absorbed during its growth, which means there's no net gain of CO2 in the atmosphere.

To make bioelectricity, crop is burned and the steam is used to turn the turbines of a generator. Ethanol is produced through fermentation and distillation.

The study's authors hope it will be used to expand the discussion from how we can best produce and market ethanol to how we can use our land most efficiently.

(Photo: University of California at Merced.)