Lightning??? It is those gods up there when they are really mad on their people, typically that’s we heard from our myths but we have done enough studies to understand what actually makes it happen. When we were kids we would have wondered about these stuffs which lits the whole sky and disappears with a roar. I’ve scared pretty well and i still remember those days whenever on seeing the lightning i used to run into my grandma’s bedroom where she would end up telling some Indian chants(an Indian thing) to make my fear go away.
While coming to energy production we’ve done hell lot of stuffs to produce electricity from whatever we could get like tides, sun, river, coal etc., but till date we aren’t much successful when it comes to producing energy from renewable resources. The are lots of factor which prevents us from achieving that dream, ‘A pollution free energy production’. But have you ever thought about harvesting energy from lightning? It seems almost easy to generate power from it as all we have to do is to store that electricity which drops down from the sky and then to distribute it. If you’ve thought so then it’s not.
The clouds that roam up there has positive and negative ions in it which gets collected in some parts of the cloud and when a bunch of these charges tries to get into contact with oppositely charged ones an electric discharge occurs. Sometimes these transfer of ions may be between cloud-cloud or even cloud-land. This is what we call lightning.
Energy in lightning
A bolt of lightning contains about 5 billion joules of energy (Energy equivalent of about 145 litres of petrol) which when extracted would give around 1400 kWh of energy if it involves no loss.
This involves some numbers. Among all the lightning strikes only 1/4 of them are cloud-ground whereas a major portion of them happens within or between the clouds. As a single lightning bolt drops down, a major portion of it gets distributed to various branches and hence only a part of the bolt reached the preferred place.
It is calculated that about 350 million ground strikes occur every year and could increase in the coming days considering climate change. If we could harvest them all without any loss we would get around 490 billion kWh of energy while the world’s total consumption of energy was around 24 trillion kWh a year, as per 2016 data. Thus we would be producing 2% of total energy needed for the world which means we could power the whole world only for around 7-10 days. This may seem too small but this 2% is the total energy contributed by solar, wind, geothermal & biomass altogether a year. So it’s not quite bad to produce electricity from lightning but cost is the factor which gives other resources an upper hand while coming to production on comparison with lightning.
To harvest lightning it would take large towers about the size of Eiffel to capture considerable amount of lightning. Then the captured energy has to be transmitted via heavy duty electric circuit and stored in large capacitors else the strike which happens for some milliseconds would roast everything that is connected in the circuit.
Another idea was to capture the lightning by flying kites in the sky so that we could reduce the money that we spend on towers but it is actually impossible as the lightning has to be transmitted via heavy duty cables which will pull the kites down.
In 2007, a company called ‘Alternative energy holdings‘ attempted to do this with the help of Steve LeRoy who had been able to power a 60 watt bulb for 20 minutes from artificial lightning but it didn’t go well.
A huge amount of lightning is in the form of heat rather than electricity, the reason why we hear thunder and even if it is not possible to store we could use it to separate hydrogen from water and thus producing hydrogen to fuel all we need.There are some places with huge record for thunderstorms like
- Venezuela’s Maracaibo( 232 flashes/sq.km in a year)
- Republic of Congo
- Colombia’s Caceres(172.29 flashes/sq.km in a year).
Even in those places we can’t predict an exact location where a lightning would occur as planned. The major problem of harvesting lightning is this sporadic nature of it. However there is an idea to overcome this by shooting Laser Induced Plasma Channel (LIPC) into the sky so that we could create an ionized pathway with low resistance in the atmosphere for the lightning to drop down on to the desired location but this method has only been employed at very few instances in the name of preventing accidents due to thunderstorms so far.
Harvesting lightning energy isn’t actually possible with our present day technology but it doesn’t mean that we won’t take steps to store this energy. We can’t let this free electricity just to dissociate into the nature. The perpetual motion machines which were once a topic of discussion for free energy seems hopeless now. Who knows!! one day when we achieve this tech we could be harvesting lightning from Jupiter (its nitrogen filled atmosphere has lightning 10 times more powerful than that on Earth) to run our space missions.
For further information –
Can we harvest the energy of lightning? – How Stuff Works
Is there a way to harness electricity from lightning? – MIT