3 ms·

It seems like a better solution would be batteries and/or the allowance of dirtier power generation (in emergencies). I can't even wrap my head around the regul

It seems like a better solution would be batteries and/or the allowance of dirtier power generation (in emergencies). I can't even wrap my head around the regulatory nightmare of shutting off everyone's heat at night in January.

corty 6y ago
Batteries maybe. Allowing "dirtier" non-50Hz power would make things worse, power plant turbines are optimized for 50Hz, different frequencies get inefficient quite fast. So your generation will shrink the lower you go. At the same time generators running at different frequencies will work against each other. At the same time machines will pull the frequency down even further, landing you in a vicious circle that forces the frequency toward 0Hz. No choice but to cut power before you damage too much of the grid and equipment.
cjdell 6y ago
Perhaps I don't understand the grid properly. I thought the average frequency was always maintained at 50Hz over a 24 hour period. Having the frequency dip below 49.9Hz would normally be exceptionally rare. I mean, if the alternative is a blackout, having heating turned off for a few minutes over a 24 period would be preferable to a nationwide blackout? It's not as if people would suddenly freeze to death anyway. Just curious if someone who understood this better had a good explanation for why this might be a bad idea.
formerly_proven 6y ago
Dirtier power generation doesn't work because physics. Frequency gets too high (a few Hz or so), turbogenerators/turbines blow up. Frequency gets too low, resonances destroy them. Frequency shifts quickly, massive torque and current spikes ensue. Load is dumped, frequency ramps up quickly and voltage rises very quickly. There are a number of control and monitoring systems in a power plant which ought to prevent these from happening, but in the bigger picture this means that grid power needs to be balanced continuously in order to keep nominal frequency. This becomes challenging when an interconnect fails, because this leads to very fast load changes. The reason for 50 Hz +- 0.2 Hz isn't so much about consumers; it's about being able to run the grid. In Europe there is a long-term control loop that makes it a quite accurate 50 Hz, so synchronous motor clocks work, but that has essentially nothing to do with the normal frequency control.
- johnymnemonic 6y ago
  "Dirtier power generation doesn't work because physics. Frequency gets too high (a few Hz or so), turbogenerators/turbines blow up. Frequency gets too low, resonances destroy them." You very obviously have no idea what you are talking about. Turbines blowing up because they spin a few Hz faster? Mine never did. Turbine destroyed because of "resonances" when freq too low? Mine never did that either. Not the 1100MW one at my old job, nor the two 500MW ones at the job before that and also not the 12MW one at my current job.
  - dang 6y ago
    Hey, could you please review https://news.ycombinator.com/newsguidelines.html https://news.ycombinator.com/newsguidelines.html and stick to the rules when posting here? It's not ok to attack another user like that on this site, regardless of how wrong someone is or you feel they are. It sounds like you know a lot about this topic, which is great, but please omit personal swipes—that will make it much easier for people to learn from your posts.
avianlyric 6y ago
It’s all about speed. A power grid must be perfectly balanced at all times, there no natural storage in a power grid. If large power supplier disconnects without warning, that impact propagates at the speed of light. Other suppliers will respond by reducing their frequencies to keep voltage up, this is caused by generators physically spinning slower and converting their physical momentum into electrical energy. As you can imagine the momentum of a generator is large, but the stored energy is small compared to the rate of consumption. So you need systems that can respond within milliseconds to restore some stability. Batteries are actually one of the few technologies that can do that, but mostly your looking at shedding load. Disconnecting a consumer can happen in milliseconds, after all you just need to flip a switch (admittedly they’re very large switches). Once you shed load, then you have the time you need to spin up you “dirty” power supplies. But even the fastest response suppliers take minutes (think Hydro), not milliseconds to respond. So they’re not viable for dealing with the initial shock to the grid.
tgsovlerkhgsel 6y ago
It depends on how long you shut the heat off for. If you do it for 5 minutes while the gas plants spool up, few will notice and fewer will care.

corty 6y ago

Batteries maybe. Allowing "dirtier" non-50Hz power would make things worse, power plant turbines are optimized for 50Hz, different frequencies get inefficient quite fast. So your generation will shrink the lower you go. At the same time generators running at different frequencies will work against each other. At the same time machines will pull the frequency down even further, landing you in a vicious circle that forces the frequency toward 0Hz. No choice but to cut power before you damage too much of the grid and equipment.

cjdell 6y ago

Perhaps I don't understand the grid properly. I thought the average frequency was always maintained at 50Hz over a 24 hour period. Having the frequency dip below 49.9Hz would normally be exceptionally rare. I mean, if the alternative is a blackout, having heating turned off for a few minutes over a 24 period would be preferable to a nationwide blackout? It's not as if people would suddenly freeze to death anyway. Just curious if someone who understood this better had a good explanation for why this might be a bad idea.

formerly_proven 6y ago

Dirtier power generation doesn't work because physics. Frequency gets too high (a few Hz or so), turbogenerators/turbines blow up. Frequency gets too low, resonances destroy them. Frequency shifts quickly, massive torque and current spikes ensue. Load is dumped, frequency ramps up quickly and voltage rises very quickly. There are a number of control and monitoring systems in a power plant which ought to prevent these from happening, but in the bigger picture this means that grid power needs to be balanced continuously in order to keep nominal frequency. This becomes challenging when an interconnect fails, because this leads to very fast load changes. The reason for 50 Hz +- 0.2 Hz isn't so much about consumers; it's about being able to run the grid. In Europe there is a long-term control loop that makes it a quite accurate 50 Hz, so synchronous motor clocks work, but that has essentially nothing to do with the normal frequency control.

johnymnemonic 6y ago
"Dirtier power generation doesn't work because physics. Frequency gets too high (a few Hz or so), turbogenerators/turbines blow up. Frequency gets too low, resonances destroy them." You very obviously have no idea what you are talking about. Turbines blowing up because they spin a few Hz faster? Mine never did. Turbine destroyed because of "resonances" when freq too low? Mine never did that either. Not the 1100MW one at my old job, nor the two 500MW ones at the job before that and also not the 12MW one at my current job.
- dang 6y ago
  Hey, could you please review https://news.ycombinator.com/newsguidelines.html https://news.ycombinator.com/newsguidelines.html and stick to the rules when posting here? It's not ok to attack another user like that on this site, regardless of how wrong someone is or you feel they are. It sounds like you know a lot about this topic, which is great, but please omit personal swipes—that will make it much easier for people to learn from your posts.

avianlyric 6y ago

It’s all about speed. A power grid must be perfectly balanced at all times, there no natural storage in a power grid. If large power supplier disconnects without warning, that impact propagates at the speed of light. Other suppliers will respond by reducing their frequencies to keep voltage up, this is caused by generators physically spinning slower and converting their physical momentum into electrical energy. As you can imagine the momentum of a generator is large, but the stored energy is small compared to the rate of consumption. So you need systems that can respond within milliseconds to restore some stability. Batteries are actually one of the few technologies that can do that, but mostly your looking at shedding load. Disconnecting a consumer can happen in milliseconds, after all you just need to flip a switch (admittedly they’re very large switches). Once you shed load, then you have the time you need to spin up you “dirty” power supplies. But even the fastest response suppliers take minutes (think Hydro), not milliseconds to respond. So they’re not viable for dealing with the initial shock to the grid.

tgsovlerkhgsel 6y ago

It depends on how long you shut the heat off for. If you do it for 5 minutes while the gas plants spool up, few will notice and fewer will care.