For the past few years, researcher Haim Rabinowitch and colleagues have been pushing the idea of ‘potato power’ to deliver energy to people cut off from electricity grids. Hook up a potato to a couple of cheap metal plates, wires and LED bulbs, they argue, and it could provide lighting to remote towns and villages around the world.
They have also discovered a simple but ingenious trick to make potatoes particularly good at producing energy. “A single potato can power enough LED lamps for a room for 40 days,” claims Rabinowitch, who is based at the Hebrew University of Jerusalem.
While the basic principles of producing energy from potatoes are taught in high school science classes, yet to the surprise of Rabinowitch, no one had scientifically studied potatoes as an energy source. So in 2010, he decided to give it a try, along with PhD student Alex Goldberg, and Boris Rubinsky of the University of California, Berkeley.
They found that by simply boiling the potatoes for eight minutes, it broke down the organic tissues inside the potatoes, reducing resistance and allowing for more free movement of electrons and thus producing more energy. They also increased the energy output by slicing the potato into four or five pieces, each sandwiched by a copper and zinc plate, to make a series.
“We found we could improve the output 10 times, which made it interesting economically, because the cost of energy drops down,” says Goldberg. “It is low voltage energy,” says Rabinowitch, “but enough to construct a battery that could charge mobile phones or laptops in places where there is no grid, no power connection.
”Their cost analyses suggested that a single boiled potato battery with zinc and copper electrodes generates portable energy at an estimated $9 per kilowatt hour, which is 50-fold cheaper than a typical 1.5 volt AA alkaline cell or D cell battery, which can cost $49–84 per kilowatt hour.
It is also an estimated six times cheaper than standard kerosene lamps used in the developing world. Which raises an important question – why isn’t the potato battery already a roaring success?
First, there’s the issue of using a food for energy. Olivier Dubois, senior natural resources officer at the United Nations Food and Agriculture Organisation (FAO), says that using food for energy — like sugar cane for biofuels — must avoid depleting food stocks and competing with farmers.
“You first need to look at: are there enough potatoes to eat? Then, are we not competing with farmers making income from selling potatoes?” he explains. “So if eating potatoes is covered, selling potatoes is covered, and there are some potatoes left, then yes, it can work”
But potato advocates must surmount another problem before their idea catches on: consumer perception of potatoes. Compared with modern technologies like solar power, potatoes are perhaps less desirable as an energy source.
Basically, some people might not want to show off their potato battery to impress a neighbor.
Still, it cannot be denied that the potato battery idea works, and it appears cheap. Advocates of potato power will no doubt continue to keep chipping away.