That was better than most fireworks displays. I checked the second video but don't understand the German explanation. Is that just the initial effects of the massive amounts of voltage?
(the power of a lightning strike is much higher than that of a steelmaking arc furnace because it has much higher voltage, possible because the conductive path through the plasma is kilometers long instead of centimeters long)
youtube has automatically translated subtitles which worked pretty well here. the relevant yt-dlp flags are i think --write-sub --write-auto-sub --sub-lang en,es (season to taste) and then the j key in mpv cycles through the languages you chose. this is also possible from youtube's web ui but enormously more awkward
creating electricity is unfortunately somewhat less practical due to the low temperatures of the water, although there are some interesting experiments with deriving power from low-temperature geothermal resources using n-pentane-blown turbines, and you might be able to use that work. getting the furnace's water jacket hot enough to boil water would create the risk of a steam explosion as well as increase plumbing corrosion problems
i mean, it would create a larger risk than the one that already exists due to having a water jacket in a place where a furnace damage could mix water with molten steel—as it turns out, cooling water is already the major cause of fatal accidents in electric arc furnaces, causing several fatal electric arc furnace explosion accidents every year: https://www.aist.org/AIST/aist/AIST/Publications/safety%20fi... and this is stimulating a movement away from pressurized water jackets for electric arc furnaces (at least, if we can believe this marketing white paper from a company that sells non-pressurized electric arc furnace water-cooling systems)
you could conceivably use a different, higher-temperature coolant than water, such as molten salts or sodium, as is done in nuclear reactors, so you could have an unpressurized coolant loop (maybe even using a coolant that wouldn't react violently with molten steel the way water does) but these do have disadvantages; water has a really astonishing ability to transfer heat by nucleate boiling
but then you run into the cost issue: the reason coal plants are not able to produce electricity at a price that is competitive with solar farms is, as i understand it, that the steam-turbine and electromechanical generator part of the plant still cost more than solar power, even in very polar countries like germany, whose utility-scale photovoltaic capacity factor was 10% last i checked. it's not because of the cost of coal; even if coal was as free sunlight, they'd be uncompetitive. and the same cost problem would make it uneconomic to generate electricity from the waste heat from electric arc furnaces, even if you could get the heat out at a more useful temperature. every million dollars you hypothetically spend on recycling eaf waste heat into electricity would have produced more electricity if you had spent it on solar farms and wind turbines instead
district heating is a good idea tho. i wonder if witten is already doing it?
(admittedly maybe the capex for running the power lines to the facility is significant, but in the same proportion to the cost of the energy used as running transmission lines anywhere else)
there's a nice video illustrating the process at https://www.youtube.com/watch?v=T1CJ5NPW8MU. don't be alarmed, the part that looks like a major industrial accident is just what happens normally when they turn it on. a more detailed documentary with explanations, though unfortunately of an atypically large arc furnace, is in https://www.youtube.com/watch?v=eZRuVEfxIVI
in that particular case they say it runs 24/7