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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

#101

Post by plantain »

Kim_Bruning wrote: post #86
plantain wrote: post #65

Earlier quoted context omitted.

You grow herbs at home because it's kitsch, fun, or even convenient, not to save money. Store harvested herbs die in the fridge, electricity does not. In Australia, our government massively subsidizes putting solar panels on our roof, and batteries in our garages, for a $/kWh price wildly higher than could be achieved with economies of scale in an industrial installation. Batteries are even more egregious than solar,…

The subsidy question is interesting, but in Germany these balcony panels are ~ €600 unsubsidized (depending on the exact kit; see my numbers elsewhere in this discussion) and still pay back in 5 years. The economics work with and/or without government help.

The fact the economics of DIY make sense, is the evidence of the market/state failure. (whether they really do make sense without fanciful efficiency calculations, I leave to you).

https://www.investigativeeconomics.org/p/solar-is-only-cheap...

Re: Germany outfitted half a million balconies with solar panels

#102

Post by kragen »

echoangle wrote: post #47
paulmist wrote: post #41

Meanwhile China projected to add ~300GW of solar capacity in 2025. Germany renewables capacity for 2023 was 165GW. https://www.reuters.com/sustainability/climate-energy/chinas...

China is also 30 times larger in area than germany.

Yes, but until recently, Germany produced more electricity than China did.

Re: Germany outfitted half a million balconies with solar panels

#103

Post by kragen »

slaw wrote: post #79
paulmist wrote: post #49

Earlier quoted context omitted.

It is! Their biggest solar farms are also in the Inner Mongolia where the irradiance is twice what you get in Germany. That said the sheer scale is crazy!

Inner Mongolia is so far from populated areas that China build 2000 km electric power lines, as long as a car drive from Munich to Sicily.

The Messina Strait Bridge doesn't actually exist. Perhaps you are driving a hovercraft.

Re: Germany outfitted half a million balconies with solar panels

#104

Post by kragen »

lm28469 wrote: post #2

I'm in Germany and keep seeing these, I always wonder what a 400w poorly oriented panel getting like 3 hours of sun a day is good for. If they weren't basically free thanks to tax reduction and other tricks I assume no one would get them

That's mostly true, but you're mistaken about the reason they're basically free: it's because the costs of manufacturing them have been dropping dramatically for 20 years, thanks to (in large part Chinese) manufacturing innovations, not because of things like tax reduction.

Re: Germany outfitted half a million balconies with solar panels

#105

Post by kragen »

Kim_Bruning wrote: post #27
monero-xmr wrote: post #11

Earlier quoted context omitted.

Maybe these can pull 700 watts on a sunny day? And you’d need a battery to store it. Would likely make 50 cents a day or less in electricity, on perfect days. The cost for a battery, panels, and install would be ~1000 euro (or more if it’s a bureaucratic mess).

I just did some modelling with the help of claude (which can write 200LOC+ numpy code faster than I can) 300 Euros crappy setup, 600 euros mid-range setup, 1200 with storage. (Extra) regulations is zilch, it's legal to plug and play these things up to 800W nameplate capacity. I went with numbers for mid-range, vertical south orientation and offsetting 200W (without battery, any overproduction is wasted). This nets yo…

16–20% yearly return on investment is a hell of a lot better than the stock market.

Re: Germany outfitted half a million balconies with solar panels

#106

Post by lucb1e »

lucb1e wrote: post #12
lm28469 wrote: post #2

I'm in Germany and keep seeing these, I always wonder what a 400w poorly oriented panel getting like 3 hours of sun a day is good for. If they weren't basically free thanks to tax reduction and other tricks I assume no one would get them

Article cites manufacturers as saying that > installing a couple of 300-watt panels will give savings of up to 30% on a typical household’s electricity bill, but there are lots of variables that come with that claim. It depends on which direction the balcony faces and whether the panels are shaded part of the day. My german electricity bill is around 1200 euros a year. Sign me up for a one-time purchase of 426€ to sa…

(I'm too late and can't edit anymore, but I just noticed upon re-rereading that it says "couple of 300W panels" in the quote and not just "a 300W panel". My math (though done with a 450W panel for an example sales price) is likely off in the wrong direction. Sorry about that.)

Re: Germany outfitted half a million balconies with solar panels

#107

Post by gpm »

AnthonyMouse wrote: post #99
gpm wrote: post #89

Earlier quoted context omitted.

The systems discussed in the article aren't necessarily selling excess power back to the grid, but they are sending it back to the grid (possibly for free). Because they work by pumping power into a wall socket. They do so responsibly (fancy electronics that turn them off when the grid goes down). But it is the case where you are acknowledging that extra regulatory criteria make sense.

But in that case the regulations would only have to apply to plugging in something that doesn't do that. There shouldn't be any forms or approvals or fees for someone who buys a product that does.

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".

Re: Germany outfitted half a million balconies with solar panels

#108

Post by kragen »

lucb1e wrote: post #8
ViewTrick1002 wrote: post #7

Earlier quoted context omitted.

Storage isn’t free. But when you have it the marginal cost of an extra cycle is very low. Germany’s battery storage-related grid connection requests swell beyond 500 GW https://www.ess-news.com/2025/09/01/germanys-battery-storage...

That's like saying the cost of taking an additional bite from your food is very low once you have already bought it, if I'm understanding the continued use of marginal correctly in context?

When I buy food, the marginal cost of a bite from the food is very close to the average cost of a bite, because if I eat 5% more food this week, I have to buy 5% more food next week.

Contrast this with the case of listening to music on my stereo: if I listen to 5% more music on the stereo, I don't have to buy 5% more music, and I don't have to replace the stereo 5% sooner. The marginal cost is near zero: just the small amount of electricity the stereo uses, plus a tiny amount of wear and tear. Maybe I only listen to music three hours a week and the stereo cost me $313 and lasts for 20 years, so the average cost per hour is $0.10. But the marginal cost of listening for an additional hour this week is much lower than that.

Utility-scale batteries are more like the stereo than the food.

Re: Germany outfitted half a million balconies with solar panels

#109

Post by kragen »

lucb1e wrote: post #24
ViewTrick1002 wrote: post #14

Earlier quoted context omitted.

Assuming you have an endless supply of food but can only take one bite per day and it means tomorrows bite will be a bit smaller. These storage systems are generally warrantied as 5000-10000 cycles with 85% capacity remaining in 20 years time. Guaranteed money today is better than saving a few cycles to maybe make money in 20 years time. Now also factor in discounting the risk etc. and the calculation is given. But t…

Okay, I can follow that. I've noticed on electricitymaps.com that, for Germany, the coal component never disappears, no matter if you have optimal wind+solar conditions near the summer solstice and prices are far into the negatives. Apparently it's cheaper to let it run the power plant at negative prices for days , than to make it stop burning coal for those days. That renewables with storage would make that finally…

Typically ramping a coal plant up or down only takes a day or so, so if the prices stay negative for entire days, probably there's some kind of perverse incentive where the coal plant operator is getting paid to run the plant by someone else who is also having to pay a consumer to consume the energy generated.

Re: Germany outfitted half a million balconies with solar panels

#110

Post by kragen »

plantain wrote: post #55

This is such a total failure of state capacity. Why can the government or industry not build solar power at an industrial scale, and then bring it to people's homes via the existing infrastructure at a price that makes this kind of micro-scale setup completely uneconomical? It's bad enough when we have to put solar panels on actual roofs to reduce electricity bills. This is just absurd. Where are the economies of sca…

It may be actually better (in the welfare-economics sense) to build the micro-scale setups because the economies of scale may actually be inverted by cheap solar panels. See my analysis in https://news.ycombinator.com/item?id=45487051.
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