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Germany outfitted half a million balconies with solar panels

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Re: Germany outfitted half a million balconies with solar panels

#121

Post by ssl-3 »

sowbug wrote: post #81
geor9e wrote: post #20

Earlier quoted context omitted.

Anti‑islanding detects the power frequency and constantly tries to shift it. If the grid is on, its frequency won't budge, so the anti‑islanding doesn't trip. If the grid is off, the frequency shifts and it shuts off. A second one would just make it shut off faster.

Curious: is anti-islanding an actual feature, or a necessary behavior of any power source that adds power to the grid? I can't imagine how a second power source would work at all if it weren't syncing to the main source's AC phase. So it seems that if you implement the syncing, you get anti-islanding for free (assuming you handle the case of a missing main source phase by not providing power at all). This is a newbie…

If the question is "is it an 'actual feature' or is it 'necessary behavior'" then the answer is: Yes.

Simple grid-tied microinverters are completely incapable of doing anything without a grid to work with, and this is necessary: A non-synchronized AC generation source can't survive long before becoming an expensive puff of smoke instead.

Anti-islanding is an actual feature that is also inherent in the design of grid-tied inverters: When there is nothing for them to sync to, they output nothing.

Re: Germany outfitted half a million balconies with solar panels

#122

Post by hedora »

vineyardmike wrote: post #75
SoftTalker wrote: post #63

Earlier quoted context omitted.

[flagged]

I don’t understand this sentiment at all. They didn’t sacrifice their balcony, and this is electricity that the central utility organizations couldn’t generate. Many parts of the world don’t even allow this kind of solar panel to be used by individuals, so its legality is actually a policy success. Generally, balcony panels are hung off the side of the railing, so no space was lost. If this was blocking out windows o…

People often forget that installation costs dwarf panel and battery costs at this point. A gizmo that had 3kwh of battery (and a fan) sitting behind a well matched solar panel would sell like hotcakes, especially if it supported daisy chaining and back feeding into the grid (with safety interlocks for power outages).

Re: Germany outfitted half a million balconies with solar panels

#123

Post by kragen »

plantain wrote: post #100
GaggiX wrote: post #82

Earlier quoted context omitted.

You are completely ignoring the biggest cost: land. In a dense country like Germany, using millions of existing, "free" rooftops is vastly more efficient and economical than buying and dedicating scarce, expensive land for an industrial-scale farm. Also rooftop solar generates power at the point of consumption. This significantly reduces the need for new, expensive high-voltage transmission lines.

A hectare of land is a few hundred euros per year to rent - https://ec.europa.eu/eurostat/statistics-explained/index.php... Power consumption in the EU has flatlined and is even falling. New HV transmission lines are not needed - put the solar farms next to some of the shut down nuclear plants (as we now do with big batteries in Australia and decrepit coal plants).

For context, a hectare (10000 m²) directly facing the sun receives 10 megawatts of sunlight at 1kW/m². The city of Kiel is at 54°19' north, so at the equinox a hectare near it receives about cos(54°19') ≈ 58% of that: 5.8 megawatts. If you were to cover the whole field with horizontal solar panels with a mainstream 22% efficiency, the peak electrical power generated that day would be 1.28 megawatts. But you'd need 2.20 peak megawatts of solar modules to do it, because the modules are rated based on directly facing the sun and getting 1kW/m² of sunlight, which they could never do in this situation. According to the prices on https://www.solarserver.de/photovoltaik-preis-pv-modul-preis... those modules are currently 0.100€/Wp, so that's 280 kiloeuros of solar panels. This is about an order of magnitude more expensive than the land under them.

The average produced would only be on the order of 100–200kW, because Germany's capacity factor is for shit. Kiel is in an especially terrible place, with only about 2.7kWh/m² per day on average, according to https://solargis.com/resources/free-maps-and-gis-data?locali....

In real life people tilt the panels in a solar farm toward the sun and leave space between rows of panels so they don't shade each other even in the winter. That is because, even at today's historically record low prices, the panels cost enormously more than the land they're sitting on, so it makes sense to economize a bit on panels even at the cost of needing more land.

Re: Germany outfitted half a million balconies with solar panels

#124

Post by slow_typist »

cycomanic wrote: post #97
slow_typist wrote: post #88

Earlier quoted context omitted.

True, the cut of 19% VAT on panels, inverters (which is applicable to any household PV installation, not only on the balcony) are a subsidy but in the meantime prices came down so much that it’s not really relevant anymore. (440 Wp panels go for 60 EURO a piece and a 800 W Hoymiles inverter for around 120 so total subsidy is around 50 EURO.) Other subsidies paid for by the communal bodies are long gone. Cutting the V…

While I sort of agree that VAT exemption is a sort of subsidy it's important to remember that all other power generation typically receives the same "subsidy" because it's done by companies which don't pay VAT.

By definition, only the end customer pays VAT. But also on grid power in Germany. So no subsidy here.

Re: Germany outfitted half a million balconies with solar panels

#125

Post by kragen »

hedora wrote: post #117
melasadra wrote: post #19

Some people laugh at the 800W output. However, in Indonesia, roughly half of the 300 million people live in homes with an electricity capacity of 900W or less. Wish these kind of panels were available at that price here. We have pretty much 12 hours of sunlight every single day but household solar panel is discouraged by the state owned utilities.

The sunlight is going to follow a bell curve. Assume 800W at noon, and pessimistically approximate the curve with a triangle. That’s 400W * 12 hours. That’s 4.8 kwh per day. If your house is provisioned for 900W peak, you aren’t running a furnace, a/c, electric heat, or an EV. 4.8 kWh will go a long way in those circumstances. (It’d handle a fridge or two if you could time shift the power, or got one that’s designed…

Indonesia gets a great deal more sunlight than Germany, almost twice as much: https://solargis.com/resources/free-maps-and-gis-data?locali...

Legality can be a funny thing. Governments can make anything they want illegal. Here in Argentina it's illegal to import used capital equipment that hasn't been refurbished by the original manufacturer or to import maps that say that the Malvinas Islands aren't part of Argentina. In Thailand it's illegal to step on paper currency because the king's face is on it.

Re: Germany outfitted half a million balconies with solar panels

#126

Post by kragen »

AnthonyMouse wrote: post #113
gpm wrote: post #107

Earlier quoted context omitted.

I agree there shouldn't be, but I don't think it's surprising that in many places there are . It takes active work for the regulator to look at the product and say "this design is sound, we're sure it won't kill anyone".

It takes active work to do that but not to manually approve zillions of individual installations?

The zillions of individual installations probably aren't actually getting approved, manually or otherwise.

Re: Germany outfitted half a million balconies with solar panels

#127

Post by hedora »

kragen wrote: post #95
SoftTalker wrote: post #63

Earlier quoted context omitted.

[flagged]

Balcony solar panels isn't necessarily a bad outcome. It's enormously more resilient to natural disasters and warfare than centralized power stations, it's potentially more responsive to individual power needs than an electric regulator, and it may not even be inefficient—while solar panels in a utility-scale solar farm will have a higher capacity factor than balcony solar panels, that only saves you money on solar p…

People are still paying $10K’s for rooftop solar in the 10KW range in the US.

The numbers you quote suggest there’s going to be a black market for diy house-scale solar soon.

Re: Germany outfitted half a million balconies with solar panels

#128

Post by kragen »

slow_typist wrote: post #116
kragen wrote: post #96

Earlier quoted context omitted.

Are those retail prices? Are you buying them in a store, or what? 440Wp/60€ is only 0.136€/Wp, which is higher than the wholesale 0.100€/Wp price reported on Solarserver, but only barely. The word "diffusion" does get used in this way in English, but many native English speakers may be unfamiliar with it.

Yeah retail prices. And yes you can buy them in a store like home depot or order them on the internet but shipping is prohibitively expensive for small amounts. Cheapest source are local firms that install PV professionally and sell via kleinanzeigen.de as a side business or to get rid of excess stock. Thanks for the clarification, also on the use of the word diffusion. In social sciences it is common though, there i…

Thank you very much! Yes, it's more than a book, it's a whole intellectual movement, although maybe not a very lively one anymore.

Re: Germany outfitted half a million balconies with solar panels

#129

Post by hedora »

ssl-3 wrote: post #121
sowbug wrote: post #81

Earlier quoted context omitted.

Curious: is anti-islanding an actual feature, or a necessary behavior of any power source that adds power to the grid? I can't imagine how a second power source would work at all if it weren't syncing to the main source's AC phase. So it seems that if you implement the syncing, you get anti-islanding for free (assuming you handle the case of a missing main source phase by not providing power at all). This is a newbie…

If the question is "is it an 'actual feature' or is it 'necessary behavior'" then the answer is: Yes. Simple grid-tied microinverters are completely incapable of doing anything without a grid to work with, and this is necessary: A non-synchronized AC generation source can't survive long before becoming an expensive puff of smoke instead. Anti-islanding is an actual feature that is also inherent in the design of grid-…

It’s not necessary in that the inverters need to support it (they could just do randomly staged power ons, and the first one could pick the phase).

However, there’s a problem in addition to electrocuting utility workers (the ones around here assume islanding during outages, so that’s less of an issue now).

Say you plug the microinverter into a 16A 120V outlet in the US, and the power goes out while you’re running a 240V 40A clothes dryer. The island is definitely going to collapse at that point, and might do bad stuff on the way down.

Re: Germany outfitted half a million balconies with solar panels

#130

Post by kragen »

hedora wrote: post #127
kragen wrote: post #95

Earlier quoted context omitted.

Balcony solar panels isn't necessarily a bad outcome. It's enormously more resilient to natural disasters and warfare than centralized power stations, it's potentially more responsive to individual power needs than an electric regulator, and it may not even be inefficient—while solar panels in a utility-scale solar farm will have a higher capacity factor than balcony solar panels, that only saves you money on solar p…

People are still paying $10K’s for rooftop solar in the 10KW range in the US. The numbers you quote suggest there’s going to be a black market for diy house-scale solar soon.

I'm imagining autonomous intercontinental narcosubs full of solar panels navigating upriver and mooring under trees on a rainy night, met by hard-boiled crews of heavily tattooed solar panel installers with gold teeth toting AK-47s, who load the illicit panels into a beer delivery truck.
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