What is shows is that the cost of intermittent renewable energy sources is higher than we have been told because you either need significant amounts of storage which is massively expensive, or redundant non-intermittent capacity that sits in standby, or most likely both. Renewable energy can and probably should be part of the mix, but when it gets over a certain threshold, the costs to ensure stability of the network will increase beyond an acceptable level in most countries.
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The article‘s still only loads of handwaving, speculation and FUD.
What we do know: Some 15 GW of generation suddenly disappeared on shortest notice. As of yet, nobody knows what happened there (there are some valid reasons to speculate a certain root cause, see below). These 15 GWs are hard to compensate on such shortest notice: What definitely is *not* sufficient is inertia of power plant generator equipment! Way too little energy stores in there to make a dent. Yet the article loudly whines about lacking inertia:
„Traditional power stations provide stability through massive spinning turbines that help regulate frequency. Renewables, in contrast, do not naturally contribute this stabilizing inertia.“
Again, what a load of horse manure.
When the Australian Victoria big battery has already proven over and over again that inverters (battery storage systems in that case) can provide grid stabilization and regulation services much faster than these „massive spinning turbines“ – so much so that iVictoria big battery effectively shut out these generator plants from regulation market.
So what was more likely the culprit?
Bad PV system inverter trip settings.
For safety and stability reasons, inverters (or also big generation systems like plants) will ‚trip‘ and shut off if frequency deviation becomes too big.
In earlier days, for solar or wind power systems, the limit was often 0.2 Hz deviation. Which means if due to instability, over generation or under generation, the frequency rose above 50.2 Hz or fell below 49.8 Hz, the inverters would shout off.
Which was ok as long as solar, wind generation was only a small part of overall power generation.
In Germany e.g., all larger old systems had to be retrofitted to allow larger deviations (and also to have a wider distribution of different trip settings, so that not all systems behaved the same at the same time).
Turning to the Spain blackout:
Irrespective of whether the root cause was the French-Spanish interconnect failing, or a rare atmospheric effect, the net showed a sudden spike-like drop in frequency to 49.85 Hz, as reported by gridradar.net. Taking into account reporting, sampling limitations, the actual drop in some net regions was most likely more.
Which brings is to 49.8 Hz trip settings.
If enough generation capacity was triggered to trip, this will have started a cascade effect.
Which would explain how the huge amount of 15 GW generation can disappear on short notice.
Is this really the reason?
At present: Who knows. But similar (although smaller) incidents have been observed in the past, so it looks plausible. And we will certainly learn in due time what it really was.
What can be done to improve net stability?
Irrespective of the as yet to be determined real reason:
Check trip settings, reconsider existing ordinances and standards fir trip settings to make sure there is no 50.2 Hz problem (or similar).
Add ‚inertia‘ to the net. But not as physical inertia of generators or flywheels, but as synthetic inertia: More easily referred to as grid connected battery storage. Which also helps to time shift generation to later hours.
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What is shows is that the cost of intermittent renewable energy sources is higher than we have been told because you either need significant amounts of storage which is massively expensive, or redundant non-intermittent capacity that sits in standby, or most likely both. Renewable energy can and probably should be part of the mix, but when it gets over a certain threshold, the costs to ensure stability of the network will increase beyond an acceptable level in most countries.
The article‘s still only loads of handwaving, speculation and FUD.
What we do know: Some 15 GW of generation suddenly disappeared on shortest notice. As of yet, nobody knows what happened there (there are some valid reasons to speculate a certain root cause, see below). These 15 GWs are hard to compensate on such shortest notice: What definitely is *not* sufficient is inertia of power plant generator equipment! Way too little energy stores in there to make a dent. Yet the article loudly whines about lacking inertia:
„Traditional power stations provide stability through massive spinning turbines that help regulate frequency. Renewables, in contrast, do not naturally contribute this stabilizing inertia.“
Again, what a load of horse manure.
When the Australian Victoria big battery has already proven over and over again that inverters (battery storage systems in that case) can provide grid stabilization and regulation services much faster than these „massive spinning turbines“ – so much so that iVictoria big battery effectively shut out these generator plants from regulation market.
So what was more likely the culprit?
Bad PV system inverter trip settings.
For safety and stability reasons, inverters (or also big generation systems like plants) will ‚trip‘ and shut off if frequency deviation becomes too big.
In earlier days, for solar or wind power systems, the limit was often 0.2 Hz deviation. Which means if due to instability, over generation or under generation, the frequency rose above 50.2 Hz or fell below 49.8 Hz, the inverters would shout off.
Which was ok as long as solar, wind generation was only a small part of overall power generation.
But became a problem with rising share.
Called the 50.2 Hz problem.
https://www.nsenergybusiness.com/analysis/featuredealing-with-the-50-2-hz-problem/
In Germany e.g., all larger old systems had to be retrofitted to allow larger deviations (and also to have a wider distribution of different trip settings, so that not all systems behaved the same at the same time).
Turning to the Spain blackout:
Irrespective of whether the root cause was the French-Spanish interconnect failing, or a rare atmospheric effect, the net showed a sudden spike-like drop in frequency to 49.85 Hz, as reported by gridradar.net. Taking into account reporting, sampling limitations, the actual drop in some net regions was most likely more.
Which brings is to 49.8 Hz trip settings.
If enough generation capacity was triggered to trip, this will have started a cascade effect.
Which would explain how the huge amount of 15 GW generation can disappear on short notice.
Is this really the reason?
At present: Who knows. But similar (although smaller) incidents have been observed in the past, so it looks plausible. And we will certainly learn in due time what it really was.
What can be done to improve net stability?
Irrespective of the as yet to be determined real reason:
Check trip settings, reconsider existing ordinances and standards fir trip settings to make sure there is no 50.2 Hz problem (or similar).
Add ‚inertia‘ to the net. But not as physical inertia of generators or flywheels, but as synthetic inertia: More easily referred to as grid connected battery storage. Which also helps to time shift generation to later hours.