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IANAMetallurgist. Arc furnaces for steel making already rely on cheaper off peak power, so utilization is already a factor.
by ahi 2y ago
IANAMetallurgist. Arc furnaces for steel making already rely on cheaper off peak power, so utilization is already a factor.
- s1artibartfast 2y agoI didn't think they varied their use pattern by time of day. 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.
- kragen 2y agothe normal kind of arc furnaces are shut down many times a day; it's a batch process, not a continuous one
- s1artibartfast 2y agoDo they operate 24/7? Even if it is batch process, going from 24 hours to 8 hours is like tripling plant cost vs productivity.
- kragen 2y agotripling capex vs. productivity, yes, but maybe if capex is small compared to opex, that's a worthwhile tradeoff. the one particular plant i was able to find the answer for does operate 24/7
- adgjlsfhk1 2y agodon't forget wind. there's lots of wind power and very low power consumption at night. it's probably more like 22 hours to 16
- bluGill 2y agoThey generally will run the cheapest electric rates. They commonly run only the overnight shift when electric is cheapest - it is worth paying the employees that extra money to work the overnight shift. They commonly shutdown the entire month of December for yearly maintenance - when Christmas lights add additional electric demand. They coordinate with the power company for other shutdowns.
- colechristensen 2y agoYou may be thinking of aluminum plants which can’t be shut down and restarted without significant damage, but they are indeed still throttled up and down. In that case it’s electrochemistry at high temperatures to strip the oxygen off of aluminum. If it gets cold the apparatus gets damaged, but it can be throttled down a significant percentage.
- kragen 2y agothank you, that is almost certainly what they were thinking of how much do they get throttled up and down, and how frequently? i'd like to read more about this
- avianlyric 2y agoArc furnaces tend to be first in line to voluntarily shutdown to deal with grid instability, or projected power shortages. Network operators will basically pay them equivalent amount of money as they would to buy electricity, if the furnace operator is happy to shutdown at a moment’s notice. 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.
- Gibbon1 2y agoThis is one of the reasons I believe 'base load' demand is more fungible than people assume. 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-california/ 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.
- samatman 2y agoDid you miss the stat directly underneath that? > 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.
- abakker 2y agoyou are right. The thing that is interesting is that pumping loads overall take a lot of the grid's energy, it's just that most pumps are refrigeration loads, not water transport.
- avianlyric 2y agoGreat thing about heating water, is that it stays hot after you’ve heated it. 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.
- practicemaths 2y agoWhat about tankless water heaters? You can eliminate greenhouse gas emissions for heating and be more efficient with energy usage overall.