As one of the most ubiquitous crops in the world, the potato
is poised to feed the entire world. Along the way, scientists discovered that
the popular staple of many people's diets may also have potential to help power
it as well.
A couple years ago, researchers at the Hebrew University of
Jerusalem released their finding that a potato boiled for eight minutes can
make for a battery that produces ten times the power of a raw one. Using small
units comprised of a quarter-slice of potato sandwiched between a copper
cathode and a zinc anode that's connected by a wire, agricultural science
professor Haim Rabinowitch and his team wanted to prove that a system that can
be used to provide rooms with LED-powered lighting for as long as 40 days. At
around one-tenth the cost of a typical AA battery, a potato could supply power
for cell phone and other personal electronics in poor, underdeveloped and
remote regions without access to a power grid.
To be clear, the potato is not, in and of itself, an energy
source. What the potato does is simply help conduct electricity by acting as
what’s called a salt-bridge between the two metals, allowing the electron
current to move freely across the wire to create electricity. Numerous fruits
rich in electrolytes like bananas and strawberries can also form this chemical
reaction. They're basically nature’s version of battery acid.
"Potatoes were chosen because of their availability all over including the tropics and sub-tropics," Rabinowitch told the Science and Development Network. They are the world's fourth most abundant food crop."
But besides being rich in phosphoric acid, spuds are ideal
in that they're composed of sturdy starch tissue, can be stored for months and
won’t attract insects the way, say strawberries, would. Additionally, boiling
the potato breaks down the resistance inherent in the dense flesh so that
electrons can flow more freely, which significantly bumps up the overall
electrical output. Cutting the potato up into four or five pieces, they
researchers found, made it even more efficient.
The potato battery kit, which includes two metal electrodes
and alligator clips, is easy to assemble and, some parts, such as the zinc
cathode, can be inexpensively replaced. The finished device Rabinowitch came up
with is designed so that a new boiled potato slice can be inserted in between
the electrodes after the potato runs out of juice. Alligator clips that
transport the current carrying wires are attached to the electrodes and the
negative and positive input points of the light bulb. Compared to kerosene
lamps used in many developing parts of the world, the system can provide
equivalent lighting at one-sixth the cost; it's estimated to be somewhere
around $9 per kilowatt hour and a D cell battery, for another point of
comparison, can run as much as $84 per kilowatt hour.
To really make an impact, perhaps the potato needs to stop
being so humble.