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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

#541

Post by marcosdumay »

plantain wrote: post #276
marcosdumay wrote: post #119

Earlier quoted context omitted.

The cost of solar power is close to independent of scale, so the benefit of doing those industrial scale plants is often smaller than the one for repurposing some bit of underused land. There's nothing absurd about it.

It's 10x more expensive. https://www.investigativeeconomics.org/p/solar-is-only-cheap...

From your source, it's "at least 4 times more expensive", while at the same time it doubts the correctness of the numbers on large-scale plants and thinks it's too low.

Besides, it's all numbers from 4 years ago, when people weren't all putting solar panels on their balconies. And the report about gains from scale mention things like the lack of tracking in small scale installations, that the large-scale ones haven't used for many years now. So propose that your numbers are all wrong.

Re: Germany outfitted half a million balconies with solar panels

#542

Post by nidskee »

qwertox wrote: post #537
grumpy-de-sre wrote: post #271

Earlier quoted context omitted.

Not a bad legacy for Robert Habeck (along with the wind reforms), the leader we needed but didn't deserve [1][2]. Interestingly he's recently dropped out of politics and taken a teaching role at UC Berkeley. 1. https://www.youtube.com/watch?v=oxwVR5JF8Ok 2. https://www.youtube.com/watch?v=NxnnVPO9GFU

What his enemies (CDU/AfD) don't mention is that even they wouldn't have been able to undo the stop. But being in the opposition must be a fun thing since you can say the most beautiful sounding things and never have to actually deliver anything. AfD even goes a step beyond raw stupidity because they want to destroy all the wind turbines. So not just stop the ones already delivering energy, but destroy them. They jus…

That and the long running demographic issues (that one is global).

Re: Germany outfitted half a million balconies with solar panels

#543

Post by p2detar »

stephen_g wrote: post #480
p2detar wrote: post #458

Earlier quoted context omitted.

> The only good reason to go nuclear these days is if you want the bomb, like Iran. I‘m sorry but this is just absolute nonsense. Nuclear energy is the most dense energy type humanity ever produced. To put it in one line with coal and oil is not serious. Not to mention it’s far less hazardous to human health, again compared to fossil fuels. Here is a basic comparison: > With a complete combustion or fission, approx.…

Who really cares about density? The biggest thing that means is that blowing up two or three substations can cripple an entire country’s grid. Distributed energy generation and storage is actually quite strategic for national security. It’s also massive cherry-picking to just look at refined fuel. For example, H how many tonnes of ore do you need to mine and process to produce that 1kg of uranium (at least 2.5 tonnes…

> Who really cares about density?

Everyone. If you don’t, then you need to scale. Case in point with renewables. It’s also not cherry-picking, but a well-known fact in physics. Do yourself a favor and look at the source link I posted above.

The thing about blowing up things I will just skip, because it’s not serious. If things go that far, there will be far greater problems than just that. Besides, if that’s your worry why don’t use SMRs then? Russia does.

To your 4000-5000 kWh point, you are not burning silicon here, are you? And a PV is not energy fuel, it’s a device composed of many different materials. I don’t understand your point and I can’t say more than that - my reply to GP was about fossil fuels and nuclear anyway. Not sure why you decided to jump into renewables here.

Re: Germany outfitted half a million balconies with solar panels

#544

Post by Slartie »

alexey-salmin wrote: post #525
Slartie wrote: post #457

Earlier quoted context omitted.

> Today solar panels make sense in terms of money ROI but not in terms of KWh ROI That is clearly wrong. Even the worst-case embodied energy assumptions for solar panels estimate the cost of producing a square meter of solar panel area at 2000 kWh (the best cases are around 300, see https://en.wikipedia.org/wiki/Energy_return_on_investment#Ph... ). A square meter of solar panel area produces an average of 200 kWh of…

30 years lifetime (if there are no heavy storms), 5-10 years to recoup energy, that's 3-6 EROI. Then you also need to include inverters which are energy-heavy. If we're talking of any meaningful scale, then you also need to include batteries because without them panels get shut down during sunny hours lowering the EROI even further. In the end you're lucky if you get EROI of 1.5-3. That's an extremely bad deal. All o…

> Then you also need to include inverters which are energy-heavy.

Scientific publications say otherwise. It's quite hard to come by any numbers, but page 11 of https://www.wisdomlib.org/uploads/journals/mdpi-sust/2025-vo... says that typical solar inverters require about 15 MJ/kW of power for their production in total, which would amount to approx. 4 kWh per kW of inverter power. A solar panel square meter produces about 200-250 watts of peak power, so it needs inverter power that cost about 1 kWh to build. Let's triple that, because inverters have a typical lifetime of 10 years in contrast to the 30 years of solar panels. 3 kWh for the inverter is negligible when compared with 300-2000 kWh for the panel itself. So we can just ignore that.

Batteries are interesting. According to https://www.mdpi.com/2076-3298/12/1/24, it takes about 35 kWh in total to produce 1 kWh of battery capacity. Let's say we'll need 250 Wh of capacity for our 250 WPeak solar panel square meter (the rule of 1 kWh capacity for each 1 kWp is a typical estimate applied when sizing solar installations for residential homes). That makes up about 8 or 9 kWh to produce this battery capacity. Admittedly that doesn't include the raw materials, of which the cell requires quite a few expensive ones. Unfortunately I wasn't able to find a good resource on that, so I resorted to asking ChatGPT for a rough calculation, and it came up with about 140 kWh for our 250 Wh LFP cell, which doesn't sound entirely wrong, as it assumed a cell weight of 1,5 kg and splitted that up into different materials. The weight matches what I would expect from personal experience with LFP batteries.

Basically, we can just ignore the inverter and must add about 150 kWh for the battery to our 300-2000 kWh for the panel. That does not substantially impact an EROI calculated from a 1000 kWh assumption for the panel alone.

And this is a calculation based on Germany. Again: weather conditions are far from optimal for solar in Germany. It's much better in many regions in China, where solar panels are made. They can easily achieve EROIs of 20+ with solar there, which is probably the reason why China installs absolutely HUGE numbers of panels. But according to you, they must be "delusional" over there.

Re: Germany outfitted half a million balconies with solar panels

#545

Post by LunaSea »

forty wrote: post #505
LunaSea wrote: post #483

Earlier quoted context omitted.

> Nuclear technology is a dead end. You should look at CO2 / kWh in Germany vs. France

You can also decide to look at countries which went 100% renewable and have even better CO2/kWh rating than France (Iceland, Norway, Albania for example).

Iceland has massive volcanoes and a small population.

Norway has lots of hydropower and a a small population.

Not super familiar with Albania but they seem to be in the same situation as Norway.

France already implemented hydropower wherever it was possible years ago, so that's not an option.

Also France seems to have pretty much the same CO2 / kWh than Norway.

Re: Germany outfitted half a million balconies with solar panels

#546

Post by pyrale »

toomuchtodo wrote: post #503
pyrale wrote: post #499

Earlier quoted context omitted.

Balcony solar is likely to make this worse, given Germany has low/zero electricity market prices when the sun shines. Balcony solar production means Germans don't buy solar from their utility when utility costs are low, and they do want to buy some when utility costs are high. Unsurprisingly, fixed contract prices are bound to be an average of electricity price at different times. With balcony solar, the times where…

Germany needs more battery storage, full stop. It is rapidly declining in cost, it is fast to deploy, and it will soak up excess low carbon energy (both domestic and imported from interconnectors) versus curtailment as more generation comes online. > Germany’s solar industry calls for 100 GWh 2030 grid battery target https://www.cleanenergywire.org/news/germanys-solar-industry... > German battery storage hits 22.1 GW…

Yup. Flexibility should be the thing that’s subsidized. However, I would advise against "balcony" battery subsidies, and I assume balcony solar is an electoral strategy more than an energy strategy.

Re: Germany outfitted half a million balconies with solar panels

#547

Post by forty »

LunaSea wrote: post #545
forty wrote: post #505

Earlier quoted context omitted.

You can also decide to look at countries which went 100% renewable and have even better CO2/kWh rating than France (Iceland, Norway, Albania for example).

Iceland has massive volcanoes and a small population. Norway has lots of hydropower and a a small population. Not super familiar with Albania but they seem to be in the same situation as Norway. France already implemented hydropower wherever it was possible years ago, so that's not an option. Also France seems to have pretty much the same CO2 / kWh than Norway.

Yes, situations are different I agree :) my point was just that you can pick and choose what you want to look at. We'll see how things evolve, but it's not very fair to compare the situation of France which did their switch to low carbon energy many years ago, to Germany which is currently doing it. When we have more countries with finished transition to full/mostly renewable, we can compare again.

Re: Germany outfitted half a million balconies with solar panels

#548

Post by kharak »

okucu wrote: post #530
kharak wrote: post #523

Earlier quoted context omitted.

He has been well received among left-green voters, civil servants and alike. He communicated without the usual empty political phrases, that alone brought him sympathies. He also managed the Ukraine crisis well, for instance, he was involved in quickly finding alternative gas sources after one of the Nord Stream pipelines had been destroyed. I'd say he embodied the values, policies and mannerism of his electorate bet…

>he was involved in quickly finding alternative gas sources after one of the Nord Stream pipelines The very same pipeline he helped to cover that their own ally destroyed Also what the hell is your argumentation? "Actually the people who voted him, liked him" no shit. The very same people are more in favor of war than the average Nazi back in the 30s

I made no argument, merely tried to explain why he is viewed favourably by some. I could have left out the second and last paragraph, that was more about me showing that I didn’t agree with his performance either.

Re: Germany outfitted half a million balconies with solar panels

#549

Post by Scea91 »

Pfeil wrote: post #535
Scea91 wrote: post #526

Earlier quoted context omitted.

Right at this moment Germany's electricity mix has 364gCO2eq/kWh carbon intensity, France is at 21. That is because 37% of Germany's production comes from gas and coal. Even from an environmental standpoint, France is doing much better than Germany and that is thanks to nuclear. Also, by closing operating power plants, Germany weakened European energy production at the time when we geopolitically need it the most. ht…

Still not Habecks legacy. This was decided under Merkel. Besides, CO2eq are often wrongly measured with nuclear energy, ignoring building emissions and effect on the water temperature in rivers (every summer more and more plants need to shut down because of this), etc. Even if this would be done right, there are again and again longer periods where Germany exports energy to France because their reactors are often in…

> Only a well done mix makes you resiliant.

I agree on this point, me not being anti-Nuclear doesn't mean I am anti-wind or solar. Every country has different circumstances, I live in a landlocked country with mild mountains, temperate climate and modest rivers. In our case nuclear energy seems like the most reliable and scalable option. For countries with huge coastline off-shore wind absolutely makes sense, simialrly with solar.

> Besides, CO2eq are often wrongly measured with nuclear energy, ignoring building emissions.

I think this point is overestimated. Based on a brief search, studies show nuclear carbon intensity around 6-12g, and the building emissions just around 13% of total lifetime emissions [1].

> there are again and again longer periods where Germany exports energy to France because their reactors are often in maintenance.

Valid point but the 2022 French nuclear "disaster" hasn't repeated at that scale so far. In recent years France is a net exporter to Germany. I can imagine that as with many problems in renewables having technical solutions the water temperature problem is also solvable technically.

[1] https://www.frontiersin.org/journals/energy-research/article...

Re: Germany outfitted half a million balconies with solar panels

#550

Post by toomuchtodo »

pyrale wrote: post #546
toomuchtodo wrote: post #503

Earlier quoted context omitted.

Germany needs more battery storage, full stop. It is rapidly declining in cost, it is fast to deploy, and it will soak up excess low carbon energy (both domestic and imported from interconnectors) versus curtailment as more generation comes online. > Germany’s solar industry calls for 100 GWh 2030 grid battery target https://www.cleanenergywire.org/news/germanys-solar-industry... > German battery storage hits 22.1 GW…

Yup. Flexibility should be the thing that’s subsidized. However, I would advise against "balcony" battery subsidies, and I assume balcony solar is an electoral strategy more than an energy strategy.

Lots of residential batteries being installed, as mentioned in the link https://www.ess-news.com/2025/07/18/german-battery-storage-r... above.

> By the end of the first half of 2025, Germany’s official registry of energy installations recorded nearly two million battery storage systems in operation. This figure, now unofficially but safely surpassed into July , includes a gross power capacity of 14.535 gigawatts (GW) and a usable storage capacity of nearly 22.1 gigawatt-hours (GWh).

> Photovoltaic home storage systems constitute the majority of these installations, with 1.967 million small battery storage units (up to 20 kilowatts) accounting for 11.5 GW of gross power and almost 18.3 GWh of usable capacity.

> Small photovoltaic home storage units made up the bulk of new additions, with 251,948 systems providing 1.34 GW and almost 2.7 GWh. In the medium segment, 2,418 new systems added 117.7 MW of power and 160 MWh of capacity.

> The expansion of battery storage is driven by increasing demand, highlighted by 389 hours of negative wholesale electricity prices in the first half of the year. Germany has also significantly expanded its solar power generation, with approximately 107.4 GW of photovoltaic capacity installed and over 7 GW added in the first six months of 2025.

The future of electrification is distributed, broadly speaking. Distributed assets can be orchestrated to optimize for both cost and grid stability ("VPP" aka virtual power plants). Get generation and storage as close to the load as you can.

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