Comment by nomilk 21 hours ago
> Future efforts will focus on developing technologies for capturing and storing lightning energy for potential use (Figure 7).
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!
Kuala Lumpur gets (generous assumption) about 100 lightning strikes per square kilometer per year [0].
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).
You need ~4 strikes per hour to keep up with a single large offshore wind turbine (15MW at 40% capacity factor).
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.
True that an offshore wind turbine can produce 15MW. But it can cost $100m+ just for 1 turbine (built and installed). If drones are going up anyway (to protect a city/citizens from strikes), then electricity generation is effectively free, and the marginal cost is equal to the hardware required to capture it (maybe relatively low).
Based on this and other comments in this HN thread, harnessing the lightning energy for potential use wouldn't be a replacement for a power plant. However, if the resources for the lightning energy capture are/become too cheap, this could be a replacement for solar panels. Instead of replacing the power plant, it would replace/complement electricity production of a single home/building. Maybe with big enough batteries that can capture this energy, it could become a viable solution?
> Maybe with big enough batteries that can capture this energy, it could become a viable solution?
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!).
8MWh is equivalent to a few hours of electricity generation of a wind turbine.