1d ago

‘If 1.5m Germans have them there must be something in it’: how balcony solar is taking off

www.theguardian.com ‘If 1.5m Germans have them there must be something in it’: how balcony solar is taking off

Balcony solar panels can save 30% on a typical household’s electricity bill and, with vertical surface area in cities larger than roof space, the appeal is clear

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2mo ago

‘If 1.5m Germans have them there must be something in it’: how balcony solar is taking off

www.theguardian.com /environment/2024/dec/18/if-a-million-germans-have-them-there-must-be-something-in-it-how-balcony-solar-is-taking-off

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2mo ago

‘If 1.5m Germans have them there must be something in it’: how balcony solar is taking off

www.theguardian.com /environment/2024/dec/18/if-a-million-germans-have-them-there-must-be-something-in-it-how-balcony-solar-is-taking-off

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2mo ago

‘If 1.5m Germans have them there must be something in it’: how balcony solar is taking off

www.theguardian.com /environment/2024/dec/18/if-a-million-germans-have-them-there-must-be-something-in-it-how-balcony-solar-is-taking-off

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“Plug-in solar is part of the whole array of options,”
I don't understand how this works? For our system we need an inverter that cost about $3000.- (half if it doesn't have to handle a battery), and it needs to be installed by an authorized electrician.
For a small system as the one shown, the price of panels are peanuts, the 2 panels shown should cost less than $150 combined. While the cost of inverter and getting it connected is way way higher. There's a lot more to this than not being on the roof!?! But which isn't disclosed.
The article says nothing about how the power from those panels is made usable.
- Balcony solar is a set of diy technologies that require no utility permissions.
  In Germany, NL, you can just plug it into socket and it works somehow.
  In us you can use powerstations and also adapters that sync draw from battery as it charges from ac in house.
  It pays for itself even with more expensive equipment, by not needed license, permission, that can lead to cheap efficient panels costing over 3$ per watt. Small systems that just offset use instead of selling back, have higher revenue offsets in high per kwh priced markets.
  
  In Germany, NL, you can just plug it into socket and it works somehow.
  This is incredibly dangerous as it will feed power into the grid even when the grid is down. You might say 'that is great!', yeah, well, the line technicians who cannot work on damaged cables because you are energizing them think otherwise.
  One of the reasons home solar grid-feeding systems are expensive in the US is they have extra equipment to disconnect the system from the grid if the grid goes down. Your house can still have local power, but you won't be energizing powerlines technicians are trying to fix.
  
  These plugin systems shut down automatically when there's a power outage. To make sure that they really do shut down when needed, in Belgium only plugin systems that have been approved by the network management organisation may be used. The other countries that allow these probably have similar precautions.
- The "balcony" bit isn't the defining characteristic, it shouldn't be taken literally. Some people do have their "balcony solar power" on their roofs.
  What defines it is limitation to 800 W and inverters that come with a normal Euro Type F ("Schuko") plug and no legal requirement for professional installation. A layman can literally plug it in to an existing wall socket. Given that they are capped at 800 Watts, the inverters are also the simplest type and dirt cheap (although often they are literally just software-capped and identical to higher power ones, make of that what you will). Complete systems (2 panels, cabling, inverter) cost between 299€ and 800€ depending on quality. You genuinely only have to buy a fixture that suits your needs and a mate to help you install it.
  Proper several-Kilowatt-systems are very expensive in Germany too.
  
  Thanks really good info. 👍😀
  A layman can literally plug it in to an existing wall socket
  That's amazing, I had no idea that is possible??? Is that special for Germany? (sorry for keeping on with new questions). 😋 I've never heard of that option here in Denmark.
  cost between 299€ and 800€
  No wonder it's a popular option, our system is of course bigger with 11.2 kWh and 7.5 kWh battery. but it was $17000 1½ year ago. Prices have dropped to $12500 for a similar system, but still such an 800W system is dirt cheap by comparison.
  
  Clearly not special for Germany, since the entire article is... entirely about Spain, actually.
  The option highlighted here is very interesting, but as a test of reacting to headlines vs clicking through it's an amazing case study. The German thing is a quote from a Spanish seller of this tech explaining why he's confident it will take off.
  
  I had no idea that is possible??? Is that special for Germany?
  I mean, the regulation seems to be, but there's no fancy tech going on. I'm not an electrician but I think I can explain, as I have recently tried to understand myself. To understand why it's possible it's best to understand why the limit is at 800 W precisely.
  So German wall outlets usually have a 16 A fuse and the wiring in the walls is dimensioned to accommodate slightly higher current (I think they are 2.5mm² gauge allowing up to 20 A but don't quote me on that particular part) for safety reasons. I suppose it would be the same or very similar in Denmark, or maybe most of Europe that uses 230V/50Hz AC.
  Now, normally, if you have dangerously powerful load that would melt your wires, let's say 5 kW, and you plug it in to an outlet the fuse will just pop and you're safe. If however you have a 2 kW PV system connected to a wall outlet nearby, it would theoretically be possible that your 5 kW load draws 13 A (3 kW) from the mains through the fuse and another 8.7 A (2 kW) from the PV system over the same wire in the wall that is only rated at 20 A but now carries 21.7 A. And the fuse would never pop at 13 A, making it a huge fire hazard. 800 W is basically just what will always comfortably fit into the safety margin of the wiring in German houses. All systems above 800 W need to be hardwired by professionals "behind" the fuse box so that every Amp from your PV goes through a typical 16 A fuse.
  still such an 800W system is dirt cheap by comparison
  Absolutely. I guess the low threshold for installation allows some kind of mass market economy of scale whereas systems like yours are homeowners' luxury goods.
  
  Great post! Thanks for doing the math and explaining the concepts!
  
  There are already a few requirements for operating the balcony panels, At least here in Germany:
  You need a suitable electricity meter
  You have to register with a relevant authority and inform the electricity provider that you are operating a “balcony power plant”.
  The microconverter should run on its own secured circuit. (“Should”, will certainly do very few) But technically it is simple:
  Set up panels
  Connecting necessary plugs
  Microconverter to the socket
  Be happy that you produce up to 800 watts of your own electricity
  I think it's almost irrelevant how many panels you ultimately split up. However, no more than 800 watts may be fed in.But if you have panels with, let's say, 2000 watts, you can of course charge various batteries with them beforehand. Nobody can say anything against it.
  
  Just for your information : belgium is allowing the balcony solar panels this year, but they have put limits on which you can install. The power supplier needs to have approved the kit you install. This is just to prevent people from getting cheap crap from the internet.
  Other than that, same rules!
  
  Wait really? I didn't know we finally caught up with the neighbors!
  
  Officially it's allowed after April 17th, but there's already an extensive list of approved devices.
  https://www.test-aankoop.be/woning-energie/hernieuwbare-energie/nieuws/plug-and-play-zonnepaneel
  There's probably a french version of that article as well, but test- achats/aankoop hasn't made it easy to switch languages :)
  
  You need a suitable electricity meter
  That makes sense, we also needed new meter, and that was about €200.- with installation. Not a big deal for a big installation, but for a system that can cost only €300.- an extra 200.- would be pretty significant.
- There are two main inverter approaches. One big inverter that takes the DC from a bunch of panels and converts it into AC and micro inverters where each panel gets it's own small one placed directly under the panel.
  The micro inverters cost around $150 each. So you need around 10 panels before the single inverter becomes a good choice.
  Installers love the micro because the install is easier. However as a owner with say 30 panels you now have 30 points of possible failure instead of the 1.
  
  Oh boy, apparently there's a lot I don't know. It's really cool there are those cheaper options now.
- Have a look here: https://en.m.wikipedia.org/wiki/Balcony_solar_power
  
  OK thanks, so they are indeed complete systems including inverter, so it can be connected to the grid.
  I suppose they've made some cheap low power inverters then, but the power still needs to have stable voltage an frequency and synchronization. So I wonder how cheap it's possible to make?
  I also suppose it still needs an authorized electrician to connect it? Unless Germany has some fancy system that is prepared for "plug in" connection of a local power source.
  
  In the EU, as long as it's under 800W it can be plugged directly into an outlet in your home without any kind of installation, back-feeding the grid that way.
  You're not getting paid anything for the power you send back into the grid so anything you don't use you lose.
  
  Still very cool, because selling surplus power is almost completely worthless anyway. (at least it is here)
  In the summer when you can sell, prices are generally extremely low, we have sold about twice what we use, but the value of selling is only about 5-10% on average, compared to the savings of using it ourselves. That's because the price often drop to close to zero in the middle of the day, and sometimes even below.
  Electricity itself is dirt cheap, the reason the prices are high are transportation and taxes, and short peak prices in the evening. Here transportation alone is more than the electricity itself during winter.
  And we are only paid the pure electricity price here, which I suppose is the case most places.
  
  It literally plugs into the wall.
  
  That's amazing. 😀
- If you pay 3000€ for an inverter then that's probably included installing and whatnot. You can get a cheap 50€ 4kW inverter on aliexpress, or an expensive 500€ 10kW one.
  
  No the price was not including installation, We have 11.2 kW panels and 7.5 kWh batteries. Installation was almost $5000.- !! That was probably mostly the 28 panels on the roof. But we had one installer handling everything, who was also responsible for the electrician.
  
  That's a massive installation though! Wow!
  Also, you got a biig roof!
  
  When we bought the house, that was one of the parameters on our list for "the perfect house". So the roof to the garden is also almost perfectly towards the south. 😀
  Even in January we've made 41% of our power consumption from the solar panels. 😎 You are right that it is a bit oversized according to "normal" recommendations which are 8 kWh for a house the size of ours, but we went a bit bigger in preparation for air to water heat pump, so warming the house will be electric, (currently wood pellets), and also we plan to buy an electric car within the next 2 years.
  Also it was a bit for fun, because of the movie spinal tap, so our panels go to 11 instead of just 10, because we need that little bit extra. 😋
  
  Smart planning! Thanks for the story, are you planning to go off grid or is it just to be economically free? Any batteries in the future? Excellent reference, and implementation, I'm giving you an 11 out of ten!
  
  Thanks. 😀
  Going off grid was absolutely a consideration, but only for a very short while. There are too many downsides. We would need twice as much solar capacity, and a way bigger battery, and batteries are still pretty expensive, but even with that, we would still need a generator. And we wouldn't be able to sell surplus energy. It would more than double the cost, and only provide 25% better self sufficiency for the whole year than we have now.
  We live in Denmark, and we can risk to have to go through almost all of December with only a few days sun. Running a diesel generator for power would be both noisy and smelly, It would also require more work to maintain, and it would actually cost slightly more to us a generator than to simply buy the electricity from the grid.
  Remember doubling our capacity will not bring us from 41 to 82% self sufficiency. Because there is some loss in storage, and even double our battery capacity would not be enough to store 48 kWh like we made today in the span of only 7 hours. (Today was the best day of the year yet. 😎)
  Even in January on a perfect day, we can make twice what we use, but such days are rare in January. (we use about 15 kWh per day.)
  The final problem with a generator is that we would never be able to achieve remotely the stability we have with the grid. We've been living here for 6½ year, and the power has only been out once!!!
  The problem with making it bigger than we have at all, is that after you've reached a point of above 50% self sufficiency, you are entering the area of diminishing returns quickly. On a yearly basis we are about 72% self sufficient. To reach that extra 22% probably cost 50% extra.
  This is if you live as high north as we do, because the extra capacity is only usable in the winter, in the summer it's all surplus, and you get so little for selling the power it's basically irrelevant. There is too much solar now, so when solar panels have high yields, prices often go down to almost zero.
  Going off grid is a lot easier if you live further south.
- I wonder if a whole building could use one or two inverters?
  I feel that'll make the cost reasonable
  
  For apartment buildings I don't think that's possible, since electricity is a per household connection with separate meter.

116 comments