4 ms·

Probably didn't help that before the outage hit, Spain was running its grid with very little dispatchable spinning generation, and therefore not much inertia.

Probably didn't help that before the outage hit, Spain was running its grid with very little dispatchable spinning generation, and therefore not much inertia. Solar PV/thermal + wind: ~78% Nuclear: 11.5% Co-generation: 5% Gas-fired: ~3% (less than 1GW)

JumpCrisscross 2y ago
> very little dispatchable spinning generation Makes the case for favouring flywheels over batteries.
- GeoAtreides 2y ago
  flywheels are batteries, of a different kind (and density) than lithium or lead ones.
  - vel0city 2y ago
    They're usually almost more capacitators than they are batteries from an electrical standpoint. They're there to rapidly smooth out the smaller jitters.
  - loeg 2y ago
    You know what he meant. Respond to the charitable interpretation of the comment, etc.
- tonyedgecombe 2y ago
  That's part of the UK's plan: https://www.proactiveinvestors.co.uk/companies/news/1057463/energy-grid-blackouts-to-be-warded-off-with-flywheel-storage-1057463.html https://www.proactiveinvestors.co.uk/companies/news/1057463/...
  - padjo 2y ago
    Same all over, apparently we had the biggest in the world a few years back, I’d imagine it’s been overtaken by now https://www.siemens-energy.com/global/en/home/stories/irelands-great-grid-stabilizer.html https://www.siemens-energy.com/global/en/home/stories/irelan...
    - tonyedgecombe 2y ago
      Together, the flywheel and the synchronous condenser have an inertia of 4,000 megawatt-second That's insane, imagine if it let go.
      - HPsquared 2y ago
        In electrical terms 4 GJ is 1,111 kWh. That's about 15 EV batteries' worth, or about £220 worth of retail electricity (at 20p/kWh). So it's a lot compared to the usual domestic things people are used to, but not much in grid terms. Or if you consider the Irish grid (average consumption around 5 GW) that's enough energy to power the grid for about 0.8 seconds (obviously it's not going to have enough instantaneous power output to do that, but again for a sense of scale). If Ireland had 10 of them, that'd be 8 grid-seconds worth of energy. Although, of course, actual disturbances aren't going to be that large. A few percent imbalance perhaps? So if the whole grid had an instantaneous 10% imbalance, one of those units could carry it for 8 seconds. (EDIT: changed energy numbers to fit the appropriate power grid)
- tonyarkles 2y ago
  Just to clarify this a little bit… flywheels are cool for absorbing transients and providing short-term hold-over during a blip but don’t have great long-term capacity. http://claverton-energy.com/active-power-article-flywheel-energy-storage.html http://claverton-energy.com/active-power-article-flywheel-en... as a smaller scale example. $330/kW but at that price it only has 15 seconds of carry-over, basically just enough to get the diesel generator fired up. Spinning reserve in the grid is equipment that capable of long-term generation very quickly. In the case of hydroelectric dams, they will often cut off the water supply to some of the turbines and use air pressure to push the water out of the way; the generator attached to the turning essentially turns into a motor and keeps the turbine spinning. If you need to bring it online, you open the water valve and let the air out. Similar situation with natural gas-fired simple cycle turbines. They’re sitting there running at low output. Need more? Just add fuel. For combined cycle it might take a bit for the boiler to warm up for full output but having the first stage running full tilt will get it warmed up fast.
  - alexey-salmin 2y ago
    Yeah, but the angular momentum of turbines/flywheels gives you a few seconds to cutoff consumers before the grid collapses. In a solar grid you probably have milliseconds instead of seconds, this could be the reason why the automation failed in this case.
- rcxdude 2y ago
  flywheels don't really work synchronously, though. Or at least, if so, they're not very useful as storage. Inverters can simulate inertia just fine, in fact they can simulate a much larger inertia than the corresponding power of spinning generation, leading to greater grid stability (whether connected to batteries or solar/wind, though without batteries its a little 'brittle' if you run near 100% output, as the power needed may suddenly disappear, so this is probably not good practice for the system as a whole. And you still need some give in your inertia so the grid can actually communicate about supply and demand)
pjc50 2y ago
> Solar PV/thermal + wind: ~78% This is (a) incredibly impressive to achieve and (b) definitely the point at which the battery infrastructure needs to catch up in order to reduce the risk of such incidents.
- jandrese 2y ago
  I was just thinking that grid scale batteries could be extremely useful in a black start situation.
- alexey-salmin 2y ago
  > battery infrastructure needs to catch up This non-existent technology will surely catch up very soon, I wonder what takes them so long. The only battery available at this scale is hydro and it doesn't do very well in Spain because of droughts.
  - pjc50 2y ago
    It definitely does exist, I don't know why people are weird about this: https://www.solarpowerportal.co.uk/zenobe-200mw-bess-operational-first-to-provide-stability-services-for-neso/ https://www.solarpowerportal.co.uk/zenobe-200mw-bess-operati...

JumpCrisscross 2y ago

> very little dispatchable spinning generation Makes the case for favouring flywheels over batteries.

GeoAtreides 2y ago
flywheels are batteries, of a different kind (and density) than lithium or lead ones.
- vel0city 2y ago
  They're usually almost more capacitators than they are batteries from an electrical standpoint. They're there to rapidly smooth out the smaller jitters.
- loeg 2y ago
  You know what he meant. Respond to the charitable interpretation of the comment, etc.
tonyedgecombe 2y ago
That's part of the UK's plan: https://www.proactiveinvestors.co.uk/companies/news/1057463/energy-grid-blackouts-to-be-warded-off-with-flywheel-storage-1057463.html https://www.proactiveinvestors.co.uk/companies/news/1057463/...
- padjo 2y ago
  Same all over, apparently we had the biggest in the world a few years back, I’d imagine it’s been overtaken by now https://www.siemens-energy.com/global/en/home/stories/irelands-great-grid-stabilizer.html https://www.siemens-energy.com/global/en/home/stories/irelan...
  - tonyedgecombe 2y ago
    Together, the flywheel and the synchronous condenser have an inertia of 4,000 megawatt-second That's insane, imagine if it let go.
    - HPsquared 2y ago
      In electrical terms 4 GJ is 1,111 kWh. That's about 15 EV batteries' worth, or about £220 worth of retail electricity (at 20p/kWh). So it's a lot compared to the usual domestic things people are used to, but not much in grid terms. Or if you consider the Irish grid (average consumption around 5 GW) that's enough energy to power the grid for about 0.8 seconds (obviously it's not going to have enough instantaneous power output to do that, but again for a sense of scale). If Ireland had 10 of them, that'd be 8 grid-seconds worth of energy. Although, of course, actual disturbances aren't going to be that large. A few percent imbalance perhaps? So if the whole grid had an instantaneous 10% imbalance, one of those units could carry it for 8 seconds. (EDIT: changed energy numbers to fit the appropriate power grid)
tonyarkles 2y ago
Just to clarify this a little bit… flywheels are cool for absorbing transients and providing short-term hold-over during a blip but don’t have great long-term capacity. http://claverton-energy.com/active-power-article-flywheel-energy-storage.html http://claverton-energy.com/active-power-article-flywheel-en... as a smaller scale example. $330/kW but at that price it only has 15 seconds of carry-over, basically just enough to get the diesel generator fired up. Spinning reserve in the grid is equipment that capable of long-term generation very quickly. In the case of hydroelectric dams, they will often cut off the water supply to some of the turbines and use air pressure to push the water out of the way; the generator attached to the turning essentially turns into a motor and keeps the turbine spinning. If you need to bring it online, you open the water valve and let the air out. Similar situation with natural gas-fired simple cycle turbines. They’re sitting there running at low output. Need more? Just add fuel. For combined cycle it might take a bit for the boiler to warm up for full output but having the first stage running full tilt will get it warmed up fast.
- alexey-salmin 2y ago
  Yeah, but the angular momentum of turbines/flywheels gives you a few seconds to cutoff consumers before the grid collapses. In a solar grid you probably have milliseconds instead of seconds, this could be the reason why the automation failed in this case.
rcxdude 2y ago
flywheels don't really work synchronously, though. Or at least, if so, they're not very useful as storage. Inverters can simulate inertia just fine, in fact they can simulate a much larger inertia than the corresponding power of spinning generation, leading to greater grid stability (whether connected to batteries or solar/wind, though without batteries its a little 'brittle' if you run near 100% output, as the power needed may suddenly disappear, so this is probably not good practice for the system as a whole. And you still need some give in your inertia so the grid can actually communicate about supply and demand)

pjc50 2y ago

> Solar PV/thermal + wind: ~78% This is (a) incredibly impressive to achieve and (b) definitely the point at which the battery infrastructure needs to catch up in order to reduce the risk of such incidents.

jandrese 2y ago
I was just thinking that grid scale batteries could be extremely useful in a black start situation.
alexey-salmin 2y ago
> battery infrastructure needs to catch up This non-existent technology will surely catch up very soon, I wonder what takes them so long. The only battery available at this scale is hydro and it doesn't do very well in Spain because of droughts.
- pjc50 2y ago
  It definitely does exist, I don't know why people are weird about this: https://www.solarpowerportal.co.uk/zenobe-200mw-bess-operational-first-to-provide-stability-services-for-neso/ https://www.solarpowerportal.co.uk/zenobe-200mw-bess-operati...