I'm sure someone in the 90's was using rockets without wires, the exhaust from the rocket made the trail. I cannot source it.
These guys charging cars shows they are not really serious, but a lot of forest fires are lightning, it's a worthy thing to control if possible.
Apollo 12, in November or December 1969, was struck by lightning due to the exhaust.
https://bigthink.com/hard-science/rocket-guided-lightning/:
“A patented new rocket design eschews the copper wire and chemically creates the lightning path. The rocket fuel is doped with small amounts of salt. Sodium chloride, calcium chloride, or cesium chloride is pulled through the motor, heated, and broken into charged ion components spewed out in the exhaust. The positively charged Cs, Ca, or Na atoms cool and bond with water molecules in the air, forming saltwater droplets. These droplets are far more electrically conductive than freshwater droplets, leaving a high-conductivity trail in the rocket’s wake.”
Patent link (https://patentimages.storage.googleapis.com/af/69/e2/0303f86...) says it was filed in 2001, however, not the ‘90s.
Aren't lightning conditions often preceded by strong winds and poor weather conditions? Not a great time to be flying drones. And the approach seems more complicated than simply installing lightning rods.
I'd sooner envision people using the technique to get a kick out of throwing lightning around like they're Zeus.
Well, the drone would be tethered by the ground attached wire, so it might not need to be that controllable. Elevation is the main concern, so as long as it can reach the right altitude, the tether could keep it reasonably in the right area.
I assume if there's a business case, they'll eventually automate this with drone swarms that wait in cabinets on building rooftops.
From a military standpoint, I wonder what it would take to discharge into a vulnerable area...
I can't believe that's a practical solution. Surely just installing more lighting road is simpler et more effective. They just want to do something cool and try to justify it sideways.
I'd be shocked if that worked.
[1] https://www.treehugger.com/how-much-energy-is-in-lightning-8...
In fact a quick back of the napkin math suggests it would only power a city of a million people for half a second.
Back of the napkin math suggests that even with theoretically perfect prediction, capture, storage and distribution you’d still get at best ~1% of the US’ energy through lightning capture.
Recontextualise it as harvesting electrostatic potential from the atmosphere and you see that potential is driven by the Sun.
Power is energy per time unit (thus: energy = power x time), so while the power of a lightning strike is very high (~10GW), the overall energy isn't because it only lasts for a very short duration (apparently the duration of a lightning event is hard to define, [1] says about 0,5 seconds, other places mention much shorter durations, ~10us). So if that 10GW lasts for 0,5 seconds, the total energy is 1,4MWh, which is 1/6 to 1/10 of the electrical energy an average American household consumes in a year[2].
[1] https://amt.copernicus.org/articles/16/547/2023/ [2] https://www.eia.gov/energyexplained/use-of-energy/electricit...
Right at the bottom under Frequently Asked Questions:
How much lightning would we need to capture to power the entire U.S. electricity grid?
Merely capturing the energy from 115 lightning strikes would supply all of the U.S.'s annual electricity needs.I think we'd have a very different relationship to lightning if each of them were 2200 nuke's worth of energy.
Incidentally, this puts the US electrical power generation per year at 250,000 bombs/year, which is an intriguing way of looking at it.
[1]: https://en.wikipedia.org/wiki/Electricity_sector_of_the_Unit...
[2]: https://www.google.com/search?hl=en&q=4178%20terawatt%20hour...
[3]: https://www.justintools.com/unit-conversion/energy.php?k1=hi...
According to a quick search, a typical lightning strike carries about 1-5 billion joules of energy, equivalent to roughly 250-1500kWh; enough energy to power a typical home for 10-60 days. But larger bolts of lightning can have up to 8000kWh, almost a year's supply of electricity for a home in a single bolt!
If a single drone could service a lot of square km, then it could conceivably collect a lot of electricity. E.g. if it could service 20 square km: 20 * 100 * 8mWh = 16gWh per year. Not bad, but an upper bound, and it hinges a lot on that first parameter (service area).
That would mean 350km² just to match a single wind turbine (at 100% capture efficiency for 5GJ lightning strikes).
This is not ever gonna make economical sense.
If you wanted a single buffer for the whole 350km², you'd need transmission capability from any point (or any drone launch station) to your central buffer in the Terawatt range (currently our highest power grid links are in the ~10GW range, so this is pure fantasy already). Utilization (~ capacity factor) for the lighting capture infrastructure would also be abysmally low. You'd basically need to build a ~10TW (generous estimate!) system, where costs in a lot of components directly scale with power, just to get ~10MW of sustained power out.
There is no way you are ever gonna compete with that $100M wind turbine; you could literally have cheap, high-field, room temperature superconductors and be gifted several warehouses worth of supercapacitors, and the whole lighning capture boondoggle still would not make any economic sense.
Every wind turbine generates power while there is wind.
Will a large percentage of drones & energy capture devices be of use while there is lightning?
No, it could not. The problem is that lighning strikes are so short, that their middling amount of energy still results in an insane amount of electrical power (for a very short time). And electrical power is the primary driver of cost in most components here.
Capturing lighning is like building literally a hundred electrical substations just to run them for 50 microseconds a day, 10 days per year. Our planet simply does not have the lighning density for this to ever work out.
All that (very expensive!) capture infrastructure would basically sit uselessly for almost all the time (even in the middle of a lightning storm!).
Edit: I read past the line where they mentioned this was in the plans.
https://www.weather.gov/safety/lightning-power
https://aviation.stackexchange.com/questions/35493/are-carbo...
It's a serious problem for carbon-fiber wind turbine blades. Fiberglas is an insulator, and doesn't have lighting problems. Aluminum is a good conductor, and doesn't have lighting problems as long as there's a good a path to ground through the hub. But carbon fiber is a resistor, so conducting a lightning strike generates heat. Some copper or aluminum wire has to go into the turbine blades to bypass this.
Ordinary -CG is 30 kA / 30 C / energy of 1 t of TNT. +CG is 10x that.
Direct hits are survived all the time by lightning rods for the past 275 years.
Long, unshielded lines of any sort can induce massive transient voltage transients (low current) that need to be protected with appropriate TVS circuits that will wear more in storm-prone areas. EMI from nearby lightning in unshielded computing systems with antennas or even without antennas can also be a factor.
> we conducted artificial lightning tests on drones equipped with the lightning protection cage. The results showed that the system withstood artificial strikes of up to 150 kA—five times greater than the average natural lightning strike—without any malfunction or damage, covering over 98% of naturally occurring lightning conditions.
"In addition, we aim to not only trigger and control lightning, but also to harness its energy. Future efforts will focus on developing technologies for capturing and storing lightning energy for potential use (Figure 7)."
Also, technology continues to improve, and this isn’t a “next year” thing.
Keeping control of those charges seems like a huge challenge, as they literally contain the electrical energy of a lightning bolt. I guess for physically plausible capacitors you'd also need to step the voltage way down (by six or eight orders of magnitude!?) before it reaches the capacitors. Are there physically-plausible transformers or other devices that could do that?
Or something that somehow captures the lightning as (lots and lots of) mechanical or thermal energy and then gradually converts that back into electricity?
Lightning is ~5GJ per strike. That means you'd need ~4 lighning strikes per hour just to keep up with a single large offshore wind turbine (15MW with 40% capacity factor).
There is also no realistic way to scale the whole thing up to significant levels of power; with the wind turbines, you just build several hundred to get into the GW range. There's simply not enough lighning to achieve that.
And the whole power buffering infrastructure that you would need would be an underutilized waste of (expensive) components.
There's never been any serious attempt at harvesting lightning at scale because a single glance at the numbers reveals how (economically) pointless an exercise it is.
Not that it don't look super cook in its own way. But I just reminds me of antennas