It is green, reliable and built using iron, water, coffee filters and carbon felt pads: it is the first battery capable of giving low cost and impact to the environment electric light in the houses of the most rural areas, like those of Sub-Saharan Africa. A startup from the Polytechnic University of Lausanne created it and is experimenting with it in a rural area of Tanzania.
With a single charge, the battery can power a Led bulb for five hours or charge a mobile phone. It consists of a rigid structure where an iron sheet, a paper one and carbon felt pads are inserted for each refill. A solution of water is then poured, mixed with salt and iron sulphate. "This solution reacts with the iron sheet, generating electricity and dissolving iron. Eventually, iron bisulphate is released, which can be thrown into the soil without damaging the environment", underlines Briac Barthes, one of the three founders of the start-up .
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Some prototypes have been produced and distributed through a local branch, managed by locals, and are now being tested with several families. "Our technology - continues the researcher - has the potential to change people's everyday lives. In one of the families that is testing it, the battery has allowed the daughter to study in the evening. Having the light can also transform the way in which people interact, increasing their opportunities for socialization in isolated and vulnerable families ".
Currently, those who live in rural areas of Tanzania use kerosene lamps, an expensive, highly flammable fuel that emits soot particles when it burns. "Breathing kerosene smoke in an enclosed space for five hours is as harmful to the lungs as smoking two packs of cigarettes," adds Barthes.
The new battery, reusable and divided into four compartments, solves many of these problems. During its use, iron bisulfate is produced, a broad liquid used as agricultural fertilizer. In addition, the battery costs half of a kerosene lamp: the base costs $ 12, while the parts to recharge it just 12 cents. After Tanzania, the company is planning to expand to other markets.