A simple recipe for light

IISc. researchers develop a lamp that runs entirely on salt water.

March 07, 2016 08:02 am | Updated 11:24 am IST - Bengaluru:

Barely half a litre of water and two spoons of salt is the recipe for light.

In a country where electricity is yet to reach millions and where dim kerosene lamps overlook the life of many in villages, researchers from Indian Institute of Science (IISc.) have developed an eco-friendly lamp that runs entirely on salt water.

The salt water-run battery is as powerful as four AA batteries, and can power an LED lamp for 1,500 hours (or a little more than two months) at a stretch.

The concept is one that most are familiar with in high school chemistry. Electricity can be produced when two electrodes (one that can readily give away its electrons, and another to accept them as easily) are dipped in an electrolyte.

Vasant Natarajan from the Physics Department of IISc. refined on this concept. A box (barely 6 cm in height, and around 11 cm in length) is made with four cells. A solution of 600 ml water and two tablespoons of salt is poured into the container and the lid, which contains a magnesium and graphite electrode, is closed. Tried and tested, the battery is now being manufactured by Suryagen Renewable Energy Ltd., which was conceived based on the ideas of Mr. Natarajan, who aims to take physics out of the lab and into the villages.

“Since we have just started, and we do not have a large number of orders, the setup costs Rs. 700 now. But, we hope to reduce it to less than Rs. 500 in the coming months through mass manufacture,” said Santosh H., head of the Product Development Team of Suryagen. Salt water or seawater, which is nearly free, has to be replaced every 100 hours or so; while, after nearly 1,500 hours of use, the magnesium electrode has to be changed. Currently, each electrode costs Rs. 50. It is this kind of conversion of simple technology, using renewable resources, that the fledgling company and the IISc. lab aim for. “Our resources are very, very large. We need to build on our technologies (which are) safer and surer in the Indian context,” said Mr. Natarajan.

IISc. researchers develop a lamp

that runs entirely on salt water

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