Tapping lightning
AP
What is the quantum of energy liberated during lightning? Can it be tapped and stored?
Deevi Prakash
Hyderabad
Lightning is an atmospheric electrical phenomenon in which a huge amount of charge is transferred from one location to another as guided by the electrostatic potential difference between different points in the clouds and the earth, in a short time. The cloud-to-ground strikes make a very large electrical current (tens of kilo amperes) flow along an extremely large potential difference.
An enormous amount of energy is involved in the process. The amount of energy, of course, varies from one to another lightning, but a typical value has been estimated to be in the range of about one billion Joules. This enormity of the natural energy has made physicists wonder on how to harness and utilize this.
The possible way is perhaps to collect and store the charge of the lightning, by using a conducting device fixed at a suitable height and running to the earth.
But one of the main problems is that lightning occurs randomly. Also, it has been observed that there are a few places (like Florida and some places in the polar Scandinavia), where lightning events are more frequent than in other places.
Good amount of understanding of the different characteristics of lightning have been achieved through systematic studies. One important finding is that the frequency of lighting increases with the height and sharpness of the conducting point on earth.
Using this information, ‘lightning capturers’ have now been designed. These are essentially towers of about 30 metres height and support a thick conducting strip meant to carry the charge to a huge capacitor bank. In order to make this method effective, an array of a larger number of such towers must be erected in the susceptible locations.
Further, scientists have designed methods of ‘calling’ a lightning from potential cloud masses. This is accomplished by shooting a cloud by a powerful laser beam, which ionizes a straight conducting track in the atmosphere connecting the cloud and the station.
Though these efforts have yielded success both in the experimental and prototype designs; apprehension on feasibility of using lightning power is often expressed due to its natural inconsistency of predictability. However, a few commercial ventures for harnessing this energy have been initiated. Further progress in this direction is expected in the future.
Dr. H. K. Sahu
Scientific Officer, IGCAR, Kalpakkam, Tamil Nadu
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