Potatoes could be the answer to cheap off-grid electricity for the approximate 1 billion people without it, according to Israeli researchers.

It was nearly a decade ago that scientists from Hebrew University of Jerusalem released their findings that a quarter of a boiled potato  could light a room with an LED bulb for as long as 40 days!

As impressive as the experiment was, it still hasn’t caught on with as much fanfare as more expensive off-grid energy solutions such as solar or wind power.

It was already known that potatoes and all sorts of electrolyte-rich foods, such as strawberries and bananas (and even compacted soil), could serve as batteries. What the Israeli researchers discovered was that simply boiling potatoes for 8 minutes increased their battery life by a factor of 10.

While some have commented that boiling potatoes takes energy on its own, a big batch could be boiled at once over fire, and the potatoes still have a long shelf life.

The potatoes are then sliced into quarters and sandwiched between a small piece of copper and zinc, connected by a wire.

The acid inside the potato forms a chemical reaction between the negatively charged zinc and positively charged copper, and when the electrons flow from one material to another, energy is released.”

The electricity generated by the potato slice is 50 times cheaper per kilowatt hour than the energy put out by a AA or D battery, and six times cheaper than the light put off by kerosene lamps in much of the developing world.

So why haven’t we lit up the world with potatoes yet?

They don’t have the publicity alternative energy sources have, and there is a stigma against using food for energy, says researcher Haim Rabinowitch.

But with over 300 million tons of potatoes produced all over the world and 10-20% of those going to waste, he says there should be plenty left over for electricity.

In the few places on earth potatoes aren’t so abundant, such as Sri Lanka, other starchy foods could be used, such as plantain piths (stems). A team of researchers there found boiled plantain piths lit an LED bulb for 500 hours.

“I think the potato has slightly better current, but the plantain pith is free, it’s something we throw away,” Physicist KD Jayasuriya of the University of Kelaniya told the BBC.