If you’ve watched the movie Back to the Future (1985), then you would undoubtedly remember the way that Doc Brown discovers a novel technique to send Marty from the year 1955 to the year 1985. In order to power the time machine, however, he needed a humongous amount of power. With no plutonium available, he surmised that only lightning carried enough energy to power the time machine. So that’s precisely what he used; since he knew precisely when and where a lightning strike would occur, he used the power of lightning to send Marty back to the future! Pretty neat, huh?
Thinking along those same lines, have you ever wondered if we can harness the energy of a lightning strike?
Every time we hear a rumble in the sky, you invariably look up and see some flashy zig-zag patterns of lightning criss-crossing the sky. Basically, lightning is an electric current that primarily forms inside clouds, but sometimes forms between the clouds and the ground, resulting in what we call a bolt of lightning.
Power of a Lightning Strike
Lightning is not only bright, but also hot! The temperature of lightning is around 27,000 degrees Celsius, which is roughly 6 times hotter than the Sun! This means that when a lightning strike occurs, it burns the surrounding air at this huge temperature. Lightning carries approximately 5 billion joules of energy, which is a massive amount. To understand it better, let’s compare it to petrol, a very common and widely used source of energy. A single bolt of lightning carries as much energy as 145 liters of petrol can produce!
Electrical energy and power have a simple relation; electric power can be calculated by dividing the value of energy by time. Since a high amount of energy is passed through the air in a infinitesimally small time (never more than a few microseconds), the electrical power associated with lightning is very high too.
Challenges of Harnessing Lightning Strikes
The first, and most devious of all challenges pertaining to harnessing a lightning strike, is its electrical power. As stated earlier, an average lightning strike contains 5 billion joules of energy. Now, this wouldn’t be a problem, except for the fact that it lasts for only a few microseconds (a very short time when we are talking about billions of joules), which complicates the whole operation. Adding to these woes is another challenge: there is no constant power observed in lightning strikes. In some lightning strikes, the power can be much higher than the average, while in others, it is fairly low. Therefore, this makes the idea of setting up a lightning-harnessing farm pretty impractical right from the outset.
Then, there is the fact that lightning strikes are totally sporadic. You never have advance knowledge of the exact location or the precise time at which a lightning strike shall occur. That makes it rather hard to snatch those instantaneous bolts of energy.
Even if you knew these details in advance, the process of capturing that huge blast of energy in such a short time would still have its own logistical implications. Given the fact that only a fraction of the total energy of a lightning strike actually reaches the ground, it becomes even more impractical to carry out such a large-scale exercise with the equipment that we have at our disposal today.
Lightning is a tremendous source of energy… there is no doubt about that. However, it’s best that you make use of it only when you are in a very, very desperate situation, such as when you’re stuck in time, and are fortunate enough to have a genius like Doc Brown standing right next to you!