Far back in Tested's history, Will and Norm undertook a bold experiment: Harness the power of the potato. Many raw potatoes were wired together into a battery, providing a medium for the current to travel from one electrode to the other. The acidity of the potato turns it into a rudimentary battery cell. Alas, the Tested potato battery never came to life. It couldn't power an LED or a digital clock. Turns out, the Tested potato battery had one fatal flaw: Its potatoes weren't boiled.
Researchers at the Hebrew University of Jerusalem discovered that potatoes boiled for eight minutes can produce a battery that's ten times more powerful than a plain old raw potato. Of course, raw potatoes have worked in science experiments for years. The Tested battery could've functioned without boiled potatoes. But boy, would it have been better.
Good enough to serve as a substitute battery to those who can't afford the real thing, even. Smithsonian Mag writes:
"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."
As the fourth most abundant crop in the world, potatoes could be a virtually limitless, dirt cheap energy source. Limitless in the sense that they'd be easily replaceable, that is--we're not going to be launching rockets into space or powering Teslas with potato batteries. "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," writes Smithsonian Mag.
Of course, the power of the boiled potato isn't a cure-all. Potato batteries will only be effective when they won't eat into a critical food supply, and the places where potatoes are grown aren't necessarily the places that need potato power. Still, if you could light a room for 40 days with a few potatoes, that could have an enormous impact on places where power is a rare commodity.