The average lightning strike contains about 1 million joules, enough energy to fry the founding father in his boots. The problem is that the energy in lightning is contained in a very short period of time, only a few microseconds. Further, to obtain that 1 million joules, one would have to handle a voltage of several million volts. Absorbing lightning and converting it to useful energy would be an extraordinary challenge indeed. But robust and dependable safety mechanisms would also need to be built to immediately contain the huge burst of energy and prevent the entire facility from being blown to bits. In addition, determining the most practical locations for capture facilities would present a huge host of problems. According to the National Oceanic and Atmospheric Administration, lightning strikes somewhere on the earth approximately 44 times every second, but most of those strikes occur in the tropics and remote mountain regions. Constructing a state-of-the-art energy conversion and storage facility in such conditions would be enormously difficult. Distributing that energy to more populous areas would add even more logistic and economic challenges.
Dear Samonto
this is basically a very old discussion. The number of 1 MegaJoule you quoted is roughly 1/3 of a KWh and thus has a value of a few cents (Euro Cent USD CENT etc). However this one or few MJ is the extractable energy of a lightning bolt when it hits some sort of metal rod connected to ground. The entire energy of a lightning bolt (which is producing some plasma channel in the air) is much higher and in the ballpark of about 1 GJ. This its really not economic to try to harvest this kind of energy...sorry..even when you use the empire state building which get hit a couple of times in each thunderstrom by lightnings(and they have lightning counters in their protection system)For more details you may like to read the doc from the DEHN company (germany)
As Fritz noted, there is not enough recoverable energy in lightning to make that economically viable under the best of circumstances..
As far as "tripping" open circuit to prevent damage from lightning, I can't even envision anything physically fast enough to work on the low us to sub us time scales required. The best protection to a direct strike I'm aware of is a spark gap which fires to shunt most of the current around the load. The spark gap is preferably pre-ionized with an internal radioactive material, to reduce latency and the resultant (highly variable) initial voltage overshoot.
A triggered spark gap is even better. This can be done electronically, either with a HV pulse on a third electrode (usually with a smaller gap than the main gap), or capacitively with an external electrode, as is done with flash lamps. For high voltages, it may be possible to apply the surge voltage to a small short-gap triggering electrode through a current limiting resistance.
Spark gaps CAN be made to handle high MA currents, but lifetime is limited due to resultant electrode erosion. (Analogous to the wear-out of MOVs.) They are also suitable only for lower frequency ac voltages, allowing the arc to quench as the current goes through zero.
For sensitive electrical (and particularly electronic) loads it is often necessary to provide a second stage of voltage clamping (MOVs or TVS diodes) with sufficient series impedance after the spark gap. This impedance may be adequately provided by sufficiently long power lines.
A line frequency isolation transformer can also be a big help here, particularly against common mode voltages when suitably Faraday shielded. The best isolation is provided by the 84 year old ferroresonant (AKA "constant voltage") transformer technology. For pros and cons, see:
ustpower.com/comparing-automatic-voltage-regulation-technologies/avr-guide-ferroresonant-transformer-type-voltage-regulator/avr-guide-ferroresonant-transformer-advantages-disadvantages/
Bruce Carsten
Short time surge, clips of by lightning arrestors the first in substations provides sufficient protection from lighting no need to put off, the circuit. As direct stroke shielded by shielding wire of substations and transmission towers. Though above 66 KV switching voltage surges are of higher amplitudes than lightning.....
Yes I agree with all the facts and discussions but in case of house hold goods just before striking if it is possible to isolate the DP then there might be a chance to save televisions or refrigerators. But practically it is very impossible to achieve this scenario anyway. In the mean time if we implement intelligent protection scheme are there any possibilities?
To add to the debate, the IEC 60071 standard gives guidance for insulation coordination. The design of an electrical installation must comply with an adequate insulation coordination, since it is not practical to disconnect the loads every time there is a thunderstorm. Regards
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