A Leaf from the Nature’s Book

In this age of blooming environmental awareness, scientists are forever looking for innovative and economic, alternate ways to produce energy. While some are actively seeking energy tools to find out where energy is going and what we can do to stop it from going there, some are looking for other renewable sources of energy like solar power. After all sunshine is free! And considering that more solar energy reaches Earth every year than the combined total of the total energy in all the fossil fuels in the ground, solar power seems to be the sensible choice. What remains to be done is to obtain a work-around to the current production of electricity, tweak it to perfection and get it out to people at economic rates.

To come up with something so useful, efficient at the same time in harmony with all the above mentioned criteria, is not that easy. Often, when scientists brainstorm to come up with such innovations, strangely what they do is getting back to basics. That is they look towards nature to see how organisms naturally deal with obstacles. And that is how an MIT professor, Daniel Nocera came up with a wonderful way to produce clean energy.

Nocera designed a solar powered device, roughly the size of a pack of playing cards, which can break water (H2O) down into hydrogen and oxygen molecules, which are both, inherently valuable in the generation of electricity.

The science the solar technology is based upon is simple. During photosynthesis, plants take energy from the sunlight i.e., the light energy, change it into chemical energy and store it for future use. Taking a leaf out of Nature’s rule-book, Nocera developed his “artificial leaf”. Using a catalyst, this leaf will break water molecules down using the low-voltage output from the solar cell. In this leaf, a silicon chip produces electrons and positively charged holes; later, catalysts on the chip use that low-voltage current to generate hydrogen and oxygen, with each gas occupying a different side of the chip.

Now the predicament is to collect the hydrogen and oxygen gases that are coming off the silicon so as to use them. Nocera is looking into it and hopes to develop an effective prototype in the next two to three years. Through such a technology came up in 1998 first, they were prepared from expensive raw materials and had a short life span. But this leaf is made entirely from cheap materials, which could fuel its use. Nocera believes that this leaf could provide up to 30 kilowatt-hours of electricity per day, which is the equivalent of a typical American household’s energy usage.
Water used need not be pure and there is the added advantage of mobility. This energy doesn’t special storage devices like batteries for later use. Nocera’s noble goal is to give energy to the poor since the cost of the silicon panel isn’t much.  This could be a boon to developing nations in Asia and Africa.

This has garnered a lot of attention world-wide including with the Indian Company, Tata. The vision is creating economically viable, pollution free methods of producing energy from sunlight. Who doesn’t want that?

Nandana Nallapu

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