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Temporary negative prices have been caused by the renewable generation which exceeded the grid demand at the time, which then evolved into the nasty feedback lo

by fuoqi 1y ago

Temporary negative prices have been caused by the renewable generation which exceeded the grid demand at the time, which then evolved into the nasty feedback loop caused by the reaction of renewable generation to those conditions. You simply do not get such situation with traditional generation, it's the direct consequence of the intermittent nature of renewables and its high ratio in the total generation. Also, have you read after the market part? Please watch this video https://www.youtube.com/watch?v=7G4ipM2qjfw https://www.youtube.com/watch?v=7G4ipM2qjfw if the last quote is gibberish to you. It discusses somewhat different issues, but the point still stands.

pkilgore 1y ago
Where is the market for someone to get paid to pump water into a reservoir and let it fall down later for $$$?
- pdpi 1y ago
  That market exists, but the window of time here is like twenty minutes. Pumps have inertia and take time to spin up, you can't HFT load and generation.
  - gusgus01 1y ago
    I'm not fully informed about pumped storage, but twenty minutes is more than enough for most hydroelectric plants to go from 0 to full power, and that's probably the case for pumped storage as well. Eg, In the case of Cruachan Power Station: “It takes just two minutes for a turbine to run up from rest to generate mode,” says Martin McGhie, Operations and Maintenance Manager at the power station. “It takes slightly longer for the turbines to run down from generate to rest, but whatever function the turbines are performing, they can reach it within a matter of minutes.” https://www.drax.com/power-generation/in-energy-storage-timing-is-everything/ https://www.drax.com/power-generation/in-energy-storage-timi...
- plorg 1y ago
  If you read the report there was a significant amount of solar being produced at low prices and being pumped for storage. Further, the pumped hydro is the first load to be disconnected to balance demand on their system.
- ncruces 1y ago
  Partly the neighboring country. Between Spain and Portugal there's 10 GW (~20% or peak load) and 100 GWh of storage (enough for a day's worth of consumption). But that takes time and requires some rebalancing, because much of that capacity is not closest to the producers. It also requires water, which becomes scarcer in the autumn (not the case here). So the price can and does become negative for a window. “High frequency trading” the spot prices probably contributed to the problem.
eldaisfish 1y ago
you are correct, but your analysis is not popular here. You will soon be presented with several reasons as to why renewable energy is not the problem and how batteries are the one true solution to these problems. The reality is that electricity is complex and that renewable energy presents a new set of problems, problems to which we do not yet have complete solutions.
floatrock 1y ago
So an incredibly cheap source of supply exceeded the demand, and the market rules and some trips caused cascading failures. Why is the problem the cheap source of supply rather than the market rules and incentives that made everything act the way it did? Your comment suggests move back to good ol' expensive fossil generation instead of looking at how to bring the market rules up to date with evolving technologies.
- martinald 1y ago
  Because the only reason that solar is still generating power at negative prices is because they are getting subsidies to do it. Otherwise they would disconnect themselves apart from in extreme scenarios (control system down or something), and I bet when you are paying many tens of thousands of euro an hour you'd get someone to fix/manually turn it off sharpish. Looks like there are a multitude of schemes of various vintages in Spain, which tl;dr basically give you a guaranteed price per MWh you generate. So imagine you get a 100eur/MWh subsidy for a (legacy) solar plant. The market price is €-20/MWh. You will still continue to produce power until the price reaches -100MW/h. Even worse are some contracts for difference (poorly thought through) which give you a guaranteed price regardless of what the market is at. So even if the price was -1,000eur/MWh the government or grid operator would still give you your €50/MWh (and the subsidy would be 1,050/MWh!). The problem is if you reform this (and it is happening worldwide) solar is much, much less appealing. Because suddenly your solar plant which was getting (say) a guaranteed 70/MWh all year round suddenly does not make money for 6 months of the year at least at peak sun hours. On top of all this, you have a lot of domestic solar in places like Spain. The grid operator _cannot_ control these assets in nearly all circumstances. They will continue to dump power into the grid regardless of the market price. This again will change but it requires an awful lot of work to retrofit invertors with remote control capability OR a lot of public backlash for charging end customers who bought solar in "good faith" now getting hit with peak time negative prices (so they change their behaviour). I think my core message would be _any_ negative power prices is a sign of market failure. Acceptable in rare extreme occurrences, but the fact most of europe has highly negative prices very frequently is telling you the grid and market design is not able to handle what is going on.
  - 1y ago
jakewins 1y ago
> caused by the reaction of renewable generation to those conditions No, that is not what the report says. It says, just like you say, that renewables reacted to market prices, causing a generation drop. It then says explicitly that synchronous generation caused oscillation, while PV plants showed a flat non-oscillating pattern. From your comments I worry there are emotional factors clouding how you're reading the report - this was a systemic failure involving many separate technologies: - Market signals - negative prices - caused a drop in PV generation (as frequently occurs) - Synchronous plants caused oscillations as a side effect - Plants procured to dampen exactly those oscillations did not deliver as requested - TSO then took measures using interconnections to stabilize via other balance area - This caused - presumed - overvoltages in distribution grids - PV inverters then shut off, as mandatory by regulatory requirement in response to over voltage You're absolutely right that PV played a large role here, but that point is diminished by making it out that PV is both the source of the initial generation drop and the source of the oscillations; it is neither. The market design caused the generation drop, synchronous generators caused the oscillations, TSO action caused distribution overvoltages and regulatory requirements on PV firmware design in response to overvoltage caused the final blackout.

by fuoqi 1y ago

pkilgore 1y ago

Where is the market for someone to get paid to pump water into a reservoir and let it fall down later for $$$?

pdpi 1y ago
That market exists, but the window of time here is like twenty minutes. Pumps have inertia and take time to spin up, you can't HFT load and generation.
- gusgus01 1y ago
  I'm not fully informed about pumped storage, but twenty minutes is more than enough for most hydroelectric plants to go from 0 to full power, and that's probably the case for pumped storage as well. Eg, In the case of Cruachan Power Station: “It takes just two minutes for a turbine to run up from rest to generate mode,” says Martin McGhie, Operations and Maintenance Manager at the power station. “It takes slightly longer for the turbines to run down from generate to rest, but whatever function the turbines are performing, they can reach it within a matter of minutes.” https://www.drax.com/power-generation/in-energy-storage-timing-is-everything/ https://www.drax.com/power-generation/in-energy-storage-timi...
plorg 1y ago
If you read the report there was a significant amount of solar being produced at low prices and being pumped for storage. Further, the pumped hydro is the first load to be disconnected to balance demand on their system.
ncruces 1y ago
Partly the neighboring country. Between Spain and Portugal there's 10 GW (~20% or peak load) and 100 GWh of storage (enough for a day's worth of consumption). But that takes time and requires some rebalancing, because much of that capacity is not closest to the producers. It also requires water, which becomes scarcer in the autumn (not the case here). So the price can and does become negative for a window. “High frequency trading” the spot prices probably contributed to the problem.

eldaisfish 1y ago

you are correct, but your analysis is not popular here. You will soon be presented with several reasons as to why renewable energy is not the problem and how batteries are the one true solution to these problems. The reality is that electricity is complex and that renewable energy presents a new set of problems, problems to which we do not yet have complete solutions.

floatrock 1y ago

So an incredibly cheap source of supply exceeded the demand, and the market rules and some trips caused cascading failures. Why is the problem the cheap source of supply rather than the market rules and incentives that made everything act the way it did? Your comment suggests move back to good ol' expensive fossil generation instead of looking at how to bring the market rules up to date with evolving technologies.

martinald 1y ago
Because the only reason that solar is still generating power at negative prices is because they are getting subsidies to do it. Otherwise they would disconnect themselves apart from in extreme scenarios (control system down or something), and I bet when you are paying many tens of thousands of euro an hour you'd get someone to fix/manually turn it off sharpish. Looks like there are a multitude of schemes of various vintages in Spain, which tl;dr basically give you a guaranteed price per MWh you generate. So imagine you get a 100eur/MWh subsidy for a (legacy) solar plant. The market price is €-20/MWh. You will still continue to produce power until the price reaches -100MW/h. Even worse are some contracts for difference (poorly thought through) which give you a guaranteed price regardless of what the market is at. So even if the price was -1,000eur/MWh the government or grid operator would still give you your €50/MWh (and the subsidy would be 1,050/MWh!). The problem is if you reform this (and it is happening worldwide) solar is much, much less appealing. Because suddenly your solar plant which was getting (say) a guaranteed 70/MWh all year round suddenly does not make money for 6 months of the year at least at peak sun hours. On top of all this, you have a lot of domestic solar in places like Spain. The grid operator _cannot_ control these assets in nearly all circumstances. They will continue to dump power into the grid regardless of the market price. This again will change but it requires an awful lot of work to retrofit invertors with remote control capability OR a lot of public backlash for charging end customers who bought solar in "good faith" now getting hit with peak time negative prices (so they change their behaviour). I think my core message would be _any_ negative power prices is a sign of market failure. Acceptable in rare extreme occurrences, but the fact most of europe has highly negative prices very frequently is telling you the grid and market design is not able to handle what is going on.
- 1y ago

jakewins 1y ago

> caused by the reaction of renewable generation to those conditions No, that is not what the report says. It says, just like you say, that renewables reacted to market prices, causing a generation drop. It then says explicitly that synchronous generation caused oscillation, while PV plants showed a flat non-oscillating pattern. From your comments I worry there are emotional factors clouding how you're reading the report - this was a systemic failure involving many separate technologies: - Market signals - negative prices - caused a drop in PV generation (as frequently occurs) - Synchronous plants caused oscillations as a side effect - Plants procured to dampen exactly those oscillations did not deliver as requested - TSO then took measures using interconnections to stabilize via other balance area - This caused - presumed - overvoltages in distribution grids - PV inverters then shut off, as mandatory by regulatory requirement in response to over voltage You're absolutely right that PV played a large role here, but that point is diminished by making it out that PV is both the source of the initial generation drop and the source of the oscillations; it is neither. The market design caused the generation drop, synchronous generators caused the oscillations, TSO action caused distribution overvoltages and regulatory requirements on PV firmware design in response to overvoltage caused the final blackout.