When lightning strikes: managing impacts on wind turbines
power-technology.com
power-technology.com
There is a potential difference over that height. Lightning strikes are quite overwhelming, but perhaps additional power could be gleaned from diffusing the pd across that height.
“Two types of lightning can occur, he says: one that starts in a thunderstorm and then propagates downwards, attaching to the turbine tip – called downward initiated lightning – and another, ‘upward lighting’, that happens when the turbine gets very tall and itself starts to generate lightning that wouldn’t otherwise occur.”
It would be interesting to see pictures and videos of lightning strikes.
There are plenty of such pictures. There's a big collection of lightning strike pictures for the Empire State Building, which has been used for lightning studies since 1935. It gets hit about 25 times a year.
The headache for wind turbines is carbon fiber. Fiberglas blades are good insulators. Aluminum blades are good conductors. But carbon fiber blades are resistors, so they can be heated and burnt by lightning. This is also a headache with aircraft using carbon fiber. In both cases, metal has to be embedded to provide a conductive path.
It becomes the age old problem of storage of electricity, but perhaps by firing a wire into clouds every few seconds, we can make mini-strikes that happen every few seconds, and then the storage problem might be solved with a capacitor and inductor bank.
On top of that, an individual wind turbine is unlikely to be struck often enough to actually make up for the investment of a potential capacitor bank that large.
Depending on the power, each 0.2-2 MW strike is equivalent to the energy produced in a few minutes to an hour of normal operation.
Here's the thing though: The Earth-sky system is a big capacitor, which discharges when its dialectric (air) breaks down to form lightning.
You can bleed this capacitor slowly before it discharges.
I believe that one way to do it is with lightning rods. Supposedly, the spiky tip of the rod concentrates charge, causing a strong local E-field which ionizes the air a little, letting a little current flow. One theory is that this prevents lightning from striking, by preventing too high a potential from building up.
If so, we may be able to harvest "lightning power" at relatively high voltages but low currents, using spiky, lightning-rod -type structures, say on top of wind turbines, that trickle into our own capacitors and power electronics.
Then, you would see nothing dramatic at all, but maybe, over the course of a few years, you would see a statistically-significant reduction in the number of lightning strikes. At most, maybe you'd occasionally see some St. Elmo's Fire on the spikes.
At massive scales you could imagine this messing with the nitrogen cycle -- I believe certain nitrogen compounds important to plants are made by lightning -- but that seems like a pretty far-off concern.
Actually, this is a pretty good article. Lots of good work back in the mid 1700s by people like Ben Franklin: https://en.m.wikipedia.org/wiki/Atmospheric_electricity#Hist...
Or, check out this delightful website: https://ionpowergroup.com/. Deep in the bowels of Government Science you can still find people who wear socks with sandals.
https://en.m.wikipedia.org/wiki/Harvesting_lightning_energy
I will note that it takes finesse, as one will notice from watching other attempts to lightning. .. whenther its universities or. ..not-smart people on YouTube trying to do it, the electrical situation needs to be optimal. .. and it helps if you directly charge a potential at your target area, in order to get good odds...
Otherwise, launching rockets with wire into thunderheads is not a gaurantee you will get a strike, as you might accidentally just bleed away the electrical potential, lightning rod style