5 ms·

I wouldn't be so quick to dismiss timerol's point as nonsense. I live in Belgium. I was doing some electrical work in my home recently. On the 29th of May, I

I wouldn't be so quick to dismiss timerol's point as nonsense. I live in Belgium. I was doing some electrical work in my home recently. On the 29th of May, I noticed two out of three phases were close to 250V instead of the intended 230V. This is the limit where inverters of solar installations switch themselves of; it indicates more solar power was being produced than could be absorbed by the grid. It turns out the day-ahead electricity market prices on that day were negative for 8 hours. As I noticed with my voltage meter, such price signals are trying to tell us something. Shielding market participants from those signals (e.g. by net metering) will cause real technical problems. I already try to be part of the solution by charging my EV around solar noon, even tough I don't have solar panels. And I will switch to dynamic hourly pricing soon. But one person voluntarily acting on price signals is not going to be enough.

jacquesm 3y ago
I already documented precisely this in another comment. Inverters switching off means that everything works exactly as designed. Negative prices are mostly on account of those producers that don't switch themselves off, such as nuclear power stations and baseline load providers that are too slow to adjust to demand or supply peaks. With 50 panels on my property (a good 12.5 KW of generating capacity based on the nameplate power of one inverter and the peak capacity provided by the other) I probably am on the large size for a domestic installation. But you don't install solar power for peak capacity, you install it for average days and not so average days when you're going to need every Watt produced. And on those days (when power is scarce) you'll find that you are still consuming from the grid. That's the only issue with solar: when you need it most it isn't there. And so everybody gets to be happy: less CO2 emitted, fewer fossil fuel tonnage burned as if there is no tomorrow and some cash back for those that invested in solar. In the long run everybody wins, in the short term some parties may have to review their spreadsheets. But those traditional suppliers definitely aren't losing money, in fact they made out like bandits over the last year or two.
jacquesm 3y ago
Oh, and as for the 'intended 230 V' -> grid voltage can be between 228 and 252 inclusive without violating the standard. Nominally it is 240 V, not 230 V. The way inverters inject power into the grid is by syncing to it and then leading the phases a bit to cause current to flow. The RMS voltage will rise as a consequence of that.
- wcoenen 3y ago
  Did you catch the "Belgium" in my comment? Here in the EU, the grid voltage is targeting 230 volt (± 10%). (Either between the two phases in a two phase system, or between phase and neutral in 3 phase systems.) This is specified by the EN 50160 standard: https://www.se.com/ww/library/SCHNEIDER_ELECTRIC/SE_LOCAL/APS/204836_1312/DraftStandard0026rev2-DraftEN501602005-05.pdf https://www.se.com/ww/library/SCHNEIDER_ELECTRIC/SE_LOCAL/AP... The range you specified sounds like the US tolerances.
  - jacquesm 3y ago
    Fair enough, but I've never seen it drop below 228 and I've never seen it go above 253 and 240 is the rough midpoint between the two. I suspect this was to accomodate the UK which did have nominal 240V so that all of Europe could be 'one standard' without the requirement for gear to have many different voltage selections. So now the only time you see 230 is when the sun isn't shining the rest of the day you're much closer to 240. Incidentally: this is also why a bunch of older appliances are at risk of burning out. If they were marginal when we were still nominally 220V then 230V was already pushing it and 253 V (still within EU tolerance, 230 x 1.1 is 253!) will definitely cause damage. Newer gear is more forgiving about this. Hence the spike in business at white goods stores during days with lots of sunshine... Older appliances typically had a whole raft of supply voltages to choose from 100, 110, 115, 120, 200, 220, 240 and sometimes even 127 and 245 and I'm pretty sure I've seen even weirder ones (150, 185 iirc). Now it's just 120 or 240 for regular consumer gear. BTW, brownouts are more of a risk than overvoltage, with brownouts a powersupply that autoranges might accidentally pick the lower voltage and then when the brownout ends magic smoke comes out.

jacquesm 3y ago

I already documented precisely this in another comment. Inverters switching off means that everything works exactly as designed. Negative prices are mostly on account of those producers that don't switch themselves off, such as nuclear power stations and baseline load providers that are too slow to adjust to demand or supply peaks. With 50 panels on my property (a good 12.5 KW of generating capacity based on the nameplate power of one inverter and the peak capacity provided by the other) I probably am on the large size for a domestic installation. But you don't install solar power for peak capacity, you install it for average days and not so average days when you're going to need every Watt produced. And on those days (when power is scarce) you'll find that you are still consuming from the grid. That's the only issue with solar: when you need it most it isn't there. And so everybody gets to be happy: less CO2 emitted, fewer fossil fuel tonnage burned as if there is no tomorrow and some cash back for those that invested in solar. In the long run everybody wins, in the short term some parties may have to review their spreadsheets. But those traditional suppliers definitely aren't losing money, in fact they made out like bandits over the last year or two.

jacquesm 3y ago

Oh, and as for the 'intended 230 V' -> grid voltage can be between 228 and 252 inclusive without violating the standard. Nominally it is 240 V, not 230 V. The way inverters inject power into the grid is by syncing to it and then leading the phases a bit to cause current to flow. The RMS voltage will rise as a consequence of that.

wcoenen 3y ago
Did you catch the "Belgium" in my comment? Here in the EU, the grid voltage is targeting 230 volt (± 10%). (Either between the two phases in a two phase system, or between phase and neutral in 3 phase systems.) This is specified by the EN 50160 standard: https://www.se.com/ww/library/SCHNEIDER_ELECTRIC/SE_LOCAL/APS/204836_1312/DraftStandard0026rev2-DraftEN501602005-05.pdf https://www.se.com/ww/library/SCHNEIDER_ELECTRIC/SE_LOCAL/AP... The range you specified sounds like the US tolerances.
- jacquesm 3y ago
  Fair enough, but I've never seen it drop below 228 and I've never seen it go above 253 and 240 is the rough midpoint between the two. I suspect this was to accomodate the UK which did have nominal 240V so that all of Europe could be 'one standard' without the requirement for gear to have many different voltage selections. So now the only time you see 230 is when the sun isn't shining the rest of the day you're much closer to 240. Incidentally: this is also why a bunch of older appliances are at risk of burning out. If they were marginal when we were still nominally 220V then 230V was already pushing it and 253 V (still within EU tolerance, 230 x 1.1 is 253!) will definitely cause damage. Newer gear is more forgiving about this. Hence the spike in business at white goods stores during days with lots of sunshine... Older appliances typically had a whole raft of supply voltages to choose from 100, 110, 115, 120, 200, 220, 240 and sometimes even 127 and 245 and I'm pretty sure I've seen even weirder ones (150, 185 iirc). Now it's just 120 or 240 for regular consumer gear. BTW, brownouts are more of a risk than overvoltage, with brownouts a powersupply that autoranges might accidentally pick the lower voltage and then when the brownout ends magic smoke comes out.