Powered by Potato: Electricity using Potato
30 Sep 2015
How do you like to eat your potatoes? Baked, fried, or boiled? The possibilities are extensive. So, too, it seems, are the alternative uses for potatoes. From vodka to a battery, potatoes are more than meets the eye.
Over the past few years, researcher Haim Rabinowitch and his colleagues have been promoting the potential merits of “potato power”. They claim it could deliver energy to people cut off from electricity grids. Apparently it is quite simple; just hook up a spud to a couple of cheap metal plates, wires and LED bulbs, they argue, and something as seemingly elementary could provide lighting to remote towns and villages around the world.
Rabinowitch, of the Hebrew University in Jerusalem, told BBC that he and his colleagues have discovered potatoes to be particularly effective at producing energy, “A single potato can power enough LED lamps in a room for 40 days,” he claims.
Way back in 1780, Luigi Galvani connected two metals to the legs of a frog, causing its muscles to twitch. Since then, a great many materials have been found to have the same effect, potatoes are just one of them. Many have made what are often called “earth batteries”, simply using two metal plates and a pile of dirt, or even a bucket of water.
In conveying these ideas to high school students, teachers often use their preferred prop, a potato, however, Rabinowitch realized that nobody had ever bothered to conduct an actual scientific study into the potential of potatoes as an energy source. So he, and PhD student Alex Goldberg, decided in 2010, to fill that void.
The boys found that by boiling the potatoes for just eight minutes, organic tissues were broken down inside the potatoes, which reduced resistance and allowed freer movement of electrons; thus producing more energy. They also managed to increase the output of a single potato by slicing it into pieces in between the zinc and copper plates.
“We looked at twenty different types of potatoes,” Goldberg explained to the BBC, “and we looked at their internal resistance, which allows us to understand how much energy was lost by heat. We found we could improve the output 10 times, which made it interesting economically, because the cost of energy drops down,” he said.
Rabinowitch adds, ““It’s low voltage energy, but enough to construct a battery that could charge mobile phones or laptops in places where there is no grid, no power connection.”
When is taken into account, their cost analyses showed that one single boiled potato battery with zinc and copper electrode could generate portable energy at around $9 per kilowatt hour. To put this in perspective, it is about fifty times cheaper than your average 1.5 volt AA alkaline cell or D cell battery which range from around the $50 per kilowatt hour up to over $80. The results also show that in relative comparison to kerosene lamps used throughout the developing world, it is about six times cheaper.
The chemical reactions that take place between two dissimilar metals and the juices in the potato create a small amount of voltage that can power a very small electrical device. Still in doubt? You can follow the instructions below to make a potato-powered light bulb.
- 2 large potato
- 4 pennies
- 4 zinc-plated nails
- 5 pieces of copper wire
- A very small light bulb or LED light
Things To Do:
- Cut the potato in half, then cut a small slit into each half, large enough to slide a penny inside.
- Wrap some copper wire around each penny a few times. Use a different piece of wire for each penny.
- Stick the pennies in the slits you cut into the potato halves.
- Wrap some of the 3rd copper wire around one of the zinc-plated nails and stick the nail into one of the potato halves.
- Take the wire connected to the penny in the half of potato with the nail and wrap some of it around the 2nd nail. Stick that 2nd nail into the other potato half.
- Repeat Steps 2 to 5 for the 3rd and 4th potato.
- When you connect the two loose ends of the copper wires to the light bulb or LED it will light up.
Be careful when handling the wires, because there is a small electric charge running through the wires. Hydrogen gas may also be a byproduct of the chemical reactions in the potato, so don’t perform the experiment near open flames or strong sources of heat.
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