(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
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?
They might rely on cheaper power to lower the average cost make financial sense, but that is a different than soley utilizing excess power.
If they cant rationalize the opex running 8 hours a day, there is still a problem. My understanding is that many of these plants cant even shut down and be restarted.
Even if it is batch process, going from 24 hours to 8 hours is like tripling plant cost vs productivity.
how much do they get throttled up and down, and how frequently? i'd like to read more about this
After, to a power grid, removing large loads are functionally equivalent to adding additional generation. So if you’re operating an arc furnace, and can shutdown quickly (which arc furnaces can), then grid operators will pay you for privilege of being able to shut you down at moments notice, and then pay even more for the electricity you’re not consuming, if the grid is forced to call upon that additional “capacity” due other issues on grid.
I’m not sure if arc furnaces today vary their usage in direct response to variable electricity prices through the day, rather than only acting as emergency ballast to be jettisoned in an emergency. But I would be very surprised if they didn’t, they’re a large enough load that they’ll have coordinate the usage with their local grid, and large enough that shifting the usage pattern to avoid high cost peaks would save them a very material amount of money.
guess i failed at that
And whether you said something right or wrong I at least would have liked to see it. Especially when it gets a callout like that.
All the more reason for me to stop engaging, isn't it?
The gist of it was that nuclear power is insufficient in and of itself because it is hard to regulate output to match grid requirements, and therefore that we need both nuclear and renewable energy sources, not just one or the other. Maybe I'm wrong, maybe I'm not, I'm out of here either way.
No, I don't think so. The skepticism all comes from your initial comment, not the followups.
> The gist of it was that nuclear power is insufficient in and of itself because it is hard to regulate output to match grid requirements, and therefore that we need both nuclear and renewable energy sources, not just one or the other. Maybe I'm wrong, maybe I'm not, I'm out of here either way.
Oh well that specific point is wrong. Modern nuclear can adjust its output quickly and within a wide range if the operator wants it to. We could run a 100% nuclear grid. The fundamental issue at hand is price, not capability, because reducing output makes the cost per watt go up.
I think in California 6% of electricity demand is pumping water. I'm almost willing to go on record and say that's the California Aqueduct and the actual number is higher. Okay I'm going to look.
https://www.ppic.org/publication/water-and-energy-in-califor...
> The water system uses approximately 20% of the state’s electricity and 30% of its natural gas for business and home use, according to data from 2001—accounting for more than 5% of California’s greenhouse gas emissions.
> Heating and other energy-intensive water uses in homes and businesses make up almost 90% of water-related energy use, while treatment, pumping, and conveyance of water and wastewater account for the rest.
That's 2% for everything which isn't heating water. Pumping is some smaller fraction of that.
Water heating is basically the poster child for “demand-response” technologies. You can easily heat your water a few hours earlier than normal with basically no consequences to the user. But you need to get reasonable smart about modelling people water usage, as people don’t tend forget or forgive a cold shower.
Regardless the point is eliminating the use of natural gas in heating water is itself a benefit.
Summary the more hot water you use the smaller the win is for tankless.
Other thing I've read and seems true is gas and heat pump water heaters cost about the same to run. I installed a heat pump unit five years ago. Works okay for two people. If you had three teenage girls and a wife that likes baths a tankless would be a better choice.