7 ms·

Germans turn to balcony solar panels to save money

66 points by vinni2 2y ago

euroderf 2y ago
I very much want one of these in Finland, but our provider KSOY said no no no. Posing the question, is there a valid technical reason or is it just institutional conservatism and inertia ?
- Lichtso 2y ago
  Operating electrical power grids requires a very careful balance between production and consumption. Long term trends are regulated on the consumption side through pricing, short term jitter is regulated on the production side through switching power plants on and off. Traditionally, a power grid only had medium and large power plants, and they are not only connected to the power grid but also a control network. Adding many small power generators poses a problem in how you communicate and coordinate with them. "Connecting Solar to the Grid is Harder Than You Think" https://www.youtube.com/watch?v=7G4ipM2qjfw https://www.youtube.com/watch?v=7G4ipM2qjfw
  - Gasp0de 2y ago
    Although 800w per household shouldn't make a difference for the grid.
    - bluGill 2y ago
      800w for your house won't make a difference. Multiply by millions of households and that is real power that will make a difference.
      - tweepy 2y ago
        You could think the other way around: what prevent every citizen from a region to switch ON or OFF a 7kW load at the same time (such as an EV)
      - Gasp0de 2y ago
        800w is the maximum being produced, and not all of it will be fed into the grid. And it is unlikely that millions of households have all installed powerplants which are all oriented in the same direction and not shaded.
        bluGill 2y ago
        Germany is 84 million people. If 1% have solar and they currently average to 400 watts (half capacity from their 800 watts because of positional and shading issues) that is 33 Gigawatts. That much power if not managed will cause problems for any grid.
        Gasp0de 2y ago
        No, if 1% of them produce 400w that is actually only 320 Megawatts.
- rjsw 2y ago
  I got the feeling that people were just not telling their electricity provider that they were doing this.
- Trellmor 2y ago
  These things just plug into a power outlet. Requirement for Austria is a Smart Powermeter, because the old, analog ones would run in reverse if the solar panels produced more then you are currently using. They may not exceed 800W and are required to turn off if no power grid is detected, e.g. during a power outage. Apart from that, just institutional conservatism and inertia as far as I know.
- Ekaros 2y ago
  Because they are potentially deadly in certain failure states. Normally system you expect system to be dead when main switch is turned off. But in this case something might be feeding in power. Same goes for over current protection. You really do not want power when you expect there to be none. Even if you should always check.
  - floitsch 2y ago
    Balcony solar requires the 50Hz of the energy grid. If you turn off the main power they will stop feeding into the system.
    - tengbretson 2y ago
      So if enough of your neighbors have these panels then the grid never gets turned off.
      - WJW 2y ago
        Technically probably yes, provided you had millions of neighbors, the sun never sets and all big users like kettles and heat pumps kindly switch off as well. If either of those conditions stops being true, then either the frequency or the voltage will drop too much and the panels turn themselves off. In practice these balcony panels are not sufficient in the slightest to power a house, let alone an entire apartment building, and they will turn off almost instantly.
  - Limeray 2y ago
    [dead]
  - the-unknown-dev 2y ago
    This is not really an issue. The inverters used in these cases rely on an existing power supply for synchronization with the electrical grid. If there is no power on the socket, the inverter has no means to generate a sine wave on its own and does not provide power on its cable. This is true (as far as I know) for ALL inverters, apart from "off grid" solutions, so workers can turn off power on a street level. If that wasn't the case, there would be no way for technical staff to make sure that lines going to multiple homes (with solar) are powered off.
- InDubioProRubio 2y ago
  Have your cake and eat it ? https://solarbringer.de/solar-inselanlage-mit-netzunterstuetzung/ https://solarbringer.de/solar-inselanlage-mit-netzunterstuet...
  - ccozan 2y ago
    Yes, this is exactly my configuration! 3.5kw panels, 9kwh battery. Saves at least 1/2 of the daily power usage.
- thefz 2y ago
  In any given moment the power grid must be 1:1 for production and consumption, and lots of smaller renewables pose a problem for big operators because they need to forecast and balance.
sheepscreek 2y ago
It’s puzzling. Just the other day, it was reported that their power surplus was so significant that rates were even negative. So, why are end-users still paying high prices? Is it because of the distribution costs?
- maccard 2y ago
  The high prices people pay is the cost of having power when it’s not windy/sunny
  - patall 2y ago
    The prices were already high before wind and solar power came to be (and for quite many years grid prices where among the lowest in EU, while consumer prices where among the highest). The high consumer prices for electricity in Germany are a result of grid fees, taxes, taxes on grid fees, taxes on taxes, and a lack of political will to lower those.
    - lyu07282 2y ago
      It's a give and take between profits and taxes, a wonderful symbiosis of neoliberal politics and the oligopoly.
    - maccard 2y ago
      I live in the UK where we people point at the rest of Europe and say "why are our prices so high here when we have 50+% of our power coming from wind". > The high consumer prices for electricity in Germany are a result of grid fees Grid fees are a coverall for "making sure the whole thing runs", which in my mind covers "making sure there's gas (at least that's what we use in the UK) to cover the shortfall when it's not windy". The Gas stations need to be able to spin up to handle the demand, so it's an abritrage where you really want to maximise the amount of wind you use, while paying as little overhead to keep the gas ready to go. It's like being on-call, and having your on-call pay amortized into your regular pay.
- dagw 2y ago
goda90 2y ago
> the panels simply plug into power sockets Is there something about German electrical systems that let's this just work? I feel like everything I've read about solar for the US isn't this simple.
- dx034 2y ago
  It would work anywhere, but only with small amounts of current. In Germany the max is set to 800W. Won’t affect the grid much and standard wiring can easily handle 800W flowing „backwards“. Germany has many rented apartments compared to eg the US. If you own a house, those systems make little sense. But for Germany, where many rent an apartment, it’s attractive for many. And the only way for many to ever profit from solar.
- khafra 2y ago
  It would work with American electric systems; it's simply illegal to do that (ostensibly for safety reasons, actually for protectionist reasons (ok, maybe also because utilities don't want to build out grid-scale batteries and other smoothing solutions)).
  - InDubioProRubio 2y ago
    Which could be privatized too, if the incentives were provided. The safety reasons are actually valid. You can not safely turn off a power-topology with a N-to-N setup. The providers just cant life without that power..
  - WJW 2y ago
    The safety reasons are real though: when linesmen need to do work on the grid, it has to be depowered. This used to be easy to accomplish: just make sure the line is switched off from at the substation and you can be reasonably certain that the line is safe to work on. If Joe Random decides to send his solar power directly into the depowered grid, that would be a Bad Time for the worker involved. "Protectionist reasons" sounds nice to people who already hate big corporations, but it doesn't make a lot of sense. When the grid is down, it's down. There is no revenue to protect at that point. The actual thing they might want to protect against is big solar farms competing away revenue from fossil fuel plants, but as you'll notice such solar farms are entirely legal.
venky180 2y ago
In india, atleast in my state, they let us add solar to our roof and let us give excess energy back to the grid. And they pay us back for the energy that is sent back to the grid
- Maakuth 2y ago
  In Germany I believe the tradeoff is that you don't need to do any paperwork with your grid operator when you add a balcony powerplant, but then you're not reimbursed for the power you sell either. If you would do the paperwork, you would be paid with the excess power and could install bigger plant too. The _balcony_ implies that this is for small scale.
- nuancebydefault 2y ago
  I believe that is such almost everywhere in the world. Alternatives for excess of energy tend to be much more expensive, unless there is no grid to connect to.
  - bluGill 2y ago
    Places where they happens a lot run into issues since the sun doesn't always shine when people want power. People generally want to have a power bill of zero after installing these, but that cannot work out - they still need to pay for their share of the grid, plus whatever plan the grid as in place for nights. Depending on how many are doing this, it is possible to be in a point where there is more power than needed on the grid.
  - marcosdumay 2y ago
    That's common on places where there isn't a lot of solar back-feeding the grid. When the amount gets big enough, it short-circuits the grid's cash-flow way before it becomes a nuisance electrically, and the rules change.
jakub_g 2y ago
Related article from 3w ago: https://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 https://www.theguardian.com/environment/2024/dec/18/if-a-mil...
Gasp0de 2y ago
I'm German, and have installed a small (1.8kWp, 800W inverter) system myself. It's really pretty cool. It was really cheap (our system cost 750€ including installation material for the roof) and saves a lot of money (130€ since September). Ours will have recovered the upfront investment cost within the next 2 years. Our meter is currently turning backwards when we feed in, but will be replaced by a meter that doesn't (then, energy we feed back into the grid will be given away to the grid operator for free).
- Gasp0de 2y ago
  I forgot the coolest thing about this: We are currently transitioning from a demand-driven grid to a supply-driven grid. Previously, when more power was consumed, power plants upped their production by burning more coal, oil or gas. Now, the consumption needs to be upped when power is available via solar or wind, and reduced when it isn't. Balcony power plants do a very good job of educating and motivating people to do this.
- hagbard_c 2y ago
  Don't give energy away to the operator, they don't (want to) give you energy for free either. Get something which can soak up excess energy - a battery, an electric water heater, whatever - and run that on whatever excess energy you have. Assuming you don't invest too much money in such a project you'll end up saving a bit more money and you'll avoid being fined for pushing energy into an already overloaded network once everyone and his dog have installed solar which pushes up the voltage from nominal 230VAC to somewhere around 245-250VAC (250VAC is the usual cutoff for inverters where I live (Sweden)). I installed 14.5 kW of PV panels on the barn roof a few years ago and hooked them up to a 10 kW hybrid inverter. Hybrid inverters can divert energy (from the PV panels or from the net) to a battery which can be used at a later stage to feed consumers in the local installation or to backfeed to the net. Since we currently have a contract which allows us to sell energy at market rates we do not have a battery yet but I don't know yet what the next contract (in 2 years) will look like. Assuming that we can no longer sell at market rates I'll install around 60-80 kWh in battery capacity to soak up excess production and dump the rest in the water heater etc. If we ever get a hybrid or electric car/tractor/whatever I'll add battery capacity so as to be able to charge those with excess energy. By that time we'll be close to ready to go off-grid which is fine by me, electricity prices here in Sweden have skyrocketed due to the demand from (mostly) Germany for excess capacity since you shut down your nuclear power plants. The more transmission capacity is built in the Baltic, the higher our prices get.
starlite-5008 2y ago
[dead]
deleted 2y ago
[deleted]
jnsie 2y ago
Live in an apartment in NYC and would love some way of turning our windows into solar panels. They only thing I've seen is a ~$100 device from a company called grouphug (no affiliation) whereby a small solar panel is stuck to a window via suction cup and can charge a phone (I believe it has a small in-built battery). Laudable but I wonder if it would return the investment.
- Gasp0de 2y ago
  It won't. These systems are quite large (a single solar panel is approximately 1.2m by 1.7m (4 to 6 ft ?) and even if you put it outside with direct southern exposure and no shade it takes 2-5 years to recoup the investment cost. In the US, you pay less for electricity (in most places) so it would take longer. Behind a window, generated energy will be way less.
TacticalCoder 2y ago
A friend of mine put solar panels on the roof of his house in France. He's got a 42U rack with shitloads of servers / more than 200 TB of disks / several 4090 GPUsrendering AI stuff etc., quite the beefy setup and yet at times, on certain days and for a few hours, the solar panel are powering it all (not just the 42U rack but the entire house, including the HVAC). Quite nice.
xnx 2y ago
This seems about the perfect energy technology: affordable, self install, clear ROI, no permits necessary, no distorting subsidies.

66 points by vinni2 2y ago

I very much want one of these in Finland, but our provider KSOY said no no no. Posing the question, is there a valid technical reason or is it just institutional conservatism and inertia ?

Lichtso 2y ago
Operating electrical power grids requires a very careful balance between production and consumption. Long term trends are regulated on the consumption side through pricing, short term jitter is regulated on the production side through switching power plants on and off. Traditionally, a power grid only had medium and large power plants, and they are not only connected to the power grid but also a control network. Adding many small power generators poses a problem in how you communicate and coordinate with them. "Connecting Solar to the Grid is Harder Than You Think" https://www.youtube.com/watch?v=7G4ipM2qjfw https://www.youtube.com/watch?v=7G4ipM2qjfw
- Gasp0de 2y ago
  Although 800w per household shouldn't make a difference for the grid.
  - bluGill 2y ago
    800w for your house won't make a difference. Multiply by millions of households and that is real power that will make a difference.
    - tweepy 2y ago
      You could think the other way around: what prevent every citizen from a region to switch ON or OFF a 7kW load at the same time (such as an EV)
    - Gasp0de 2y ago
      800w is the maximum being produced, and not all of it will be fed into the grid. And it is unlikely that millions of households have all installed powerplants which are all oriented in the same direction and not shaded.
      - bluGill 2y ago
        Germany is 84 million people. If 1% have solar and they currently average to 400 watts (half capacity from their 800 watts because of positional and shading issues) that is 33 Gigawatts. That much power if not managed will cause problems for any grid.
        Gasp0de 2y ago
        No, if 1% of them produce 400w that is actually only 320 Megawatts.
rjsw 2y ago
I got the feeling that people were just not telling their electricity provider that they were doing this.
Trellmor 2y ago
These things just plug into a power outlet. Requirement for Austria is a Smart Powermeter, because the old, analog ones would run in reverse if the solar panels produced more then you are currently using. They may not exceed 800W and are required to turn off if no power grid is detected, e.g. during a power outage. Apart from that, just institutional conservatism and inertia as far as I know.
Ekaros 2y ago
Because they are potentially deadly in certain failure states. Normally system you expect system to be dead when main switch is turned off. But in this case something might be feeding in power. Same goes for over current protection. You really do not want power when you expect there to be none. Even if you should always check.
- floitsch 2y ago
  Balcony solar requires the 50Hz of the energy grid. If you turn off the main power they will stop feeding into the system.
  - tengbretson 2y ago
    So if enough of your neighbors have these panels then the grid never gets turned off.
    - WJW 2y ago
      Technically probably yes, provided you had millions of neighbors, the sun never sets and all big users like kettles and heat pumps kindly switch off as well. If either of those conditions stops being true, then either the frequency or the voltage will drop too much and the panels turn themselves off. In practice these balcony panels are not sufficient in the slightest to power a house, let alone an entire apartment building, and they will turn off almost instantly.
- Limeray 2y ago
  [dead]
- the-unknown-dev 2y ago
  This is not really an issue. The inverters used in these cases rely on an existing power supply for synchronization with the electrical grid. If there is no power on the socket, the inverter has no means to generate a sine wave on its own and does not provide power on its cable. This is true (as far as I know) for ALL inverters, apart from "off grid" solutions, so workers can turn off power on a street level. If that wasn't the case, there would be no way for technical staff to make sure that lines going to multiple homes (with solar) are powered off.
InDubioProRubio 2y ago
Have your cake and eat it ? https://solarbringer.de/solar-inselanlage-mit-netzunterstuetzung/ https://solarbringer.de/solar-inselanlage-mit-netzunterstuet...
- ccozan 2y ago
  Yes, this is exactly my configuration! 3.5kw panels, 9kwh battery. Saves at least 1/2 of the daily power usage.
thefz 2y ago
In any given moment the power grid must be 1:1 for production and consumption, and lots of smaller renewables pose a problem for big operators because they need to forecast and balance.

sheepscreek 2y ago

It’s puzzling. Just the other day, it was reported that their power surplus was so significant that rates were even negative. So, why are end-users still paying high prices? Is it because of the distribution costs?

maccard 2y ago
The high prices people pay is the cost of having power when it’s not windy/sunny
- patall 2y ago
  The prices were already high before wind and solar power came to be (and for quite many years grid prices where among the lowest in EU, while consumer prices where among the highest). The high consumer prices for electricity in Germany are a result of grid fees, taxes, taxes on grid fees, taxes on taxes, and a lack of political will to lower those.
  - lyu07282 2y ago
    It's a give and take between profits and taxes, a wonderful symbiosis of neoliberal politics and the oligopoly.
  - maccard 2y ago
    I live in the UK where we people point at the rest of Europe and say "why are our prices so high here when we have 50+% of our power coming from wind". > The high consumer prices for electricity in Germany are a result of grid fees Grid fees are a coverall for "making sure the whole thing runs", which in my mind covers "making sure there's gas (at least that's what we use in the UK) to cover the shortfall when it's not windy". The Gas stations need to be able to spin up to handle the demand, so it's an abritrage where you really want to maximise the amount of wind you use, while paying as little overhead to keep the gas ready to go. It's like being on-call, and having your on-call pay amortized into your regular pay.
dagw 2y ago

goda90 2y ago

> the panels simply plug into power sockets Is there something about German electrical systems that let's this just work? I feel like everything I've read about solar for the US isn't this simple.

dx034 2y ago
It would work anywhere, but only with small amounts of current. In Germany the max is set to 800W. Won’t affect the grid much and standard wiring can easily handle 800W flowing „backwards“. Germany has many rented apartments compared to eg the US. If you own a house, those systems make little sense. But for Germany, where many rent an apartment, it’s attractive for many. And the only way for many to ever profit from solar.
khafra 2y ago
It would work with American electric systems; it's simply illegal to do that (ostensibly for safety reasons, actually for protectionist reasons (ok, maybe also because utilities don't want to build out grid-scale batteries and other smoothing solutions)).
- InDubioProRubio 2y ago
  Which could be privatized too, if the incentives were provided. The safety reasons are actually valid. You can not safely turn off a power-topology with a N-to-N setup. The providers just cant life without that power..
- WJW 2y ago
  The safety reasons are real though: when linesmen need to do work on the grid, it has to be depowered. This used to be easy to accomplish: just make sure the line is switched off from at the substation and you can be reasonably certain that the line is safe to work on. If Joe Random decides to send his solar power directly into the depowered grid, that would be a Bad Time for the worker involved. "Protectionist reasons" sounds nice to people who already hate big corporations, but it doesn't make a lot of sense. When the grid is down, it's down. There is no revenue to protect at that point. The actual thing they might want to protect against is big solar farms competing away revenue from fossil fuel plants, but as you'll notice such solar farms are entirely legal.

venky180 2y ago

In india, atleast in my state, they let us add solar to our roof and let us give excess energy back to the grid. And they pay us back for the energy that is sent back to the grid

Maakuth 2y ago
In Germany I believe the tradeoff is that you don't need to do any paperwork with your grid operator when you add a balcony powerplant, but then you're not reimbursed for the power you sell either. If you would do the paperwork, you would be paid with the excess power and could install bigger plant too. The _balcony_ implies that this is for small scale.
nuancebydefault 2y ago
I believe that is such almost everywhere in the world. Alternatives for excess of energy tend to be much more expensive, unless there is no grid to connect to.
- bluGill 2y ago
  Places where they happens a lot run into issues since the sun doesn't always shine when people want power. People generally want to have a power bill of zero after installing these, but that cannot work out - they still need to pay for their share of the grid, plus whatever plan the grid as in place for nights. Depending on how many are doing this, it is possible to be in a point where there is more power than needed on the grid.
- marcosdumay 2y ago
  That's common on places where there isn't a lot of solar back-feeding the grid. When the amount gets big enough, it short-circuits the grid's cash-flow way before it becomes a nuisance electrically, and the rules change.

jakub_g 2y ago

Related article from 3w ago: https://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 https://www.theguardian.com/environment/2024/dec/18/if-a-mil...

Gasp0de 2y ago

I'm German, and have installed a small (1.8kWp, 800W inverter) system myself. It's really pretty cool. It was really cheap (our system cost 750€ including installation material for the roof) and saves a lot of money (130€ since September). Ours will have recovered the upfront investment cost within the next 2 years. Our meter is currently turning backwards when we feed in, but will be replaced by a meter that doesn't (then, energy we feed back into the grid will be given away to the grid operator for free).

Gasp0de 2y ago
I forgot the coolest thing about this: We are currently transitioning from a demand-driven grid to a supply-driven grid. Previously, when more power was consumed, power plants upped their production by burning more coal, oil or gas. Now, the consumption needs to be upped when power is available via solar or wind, and reduced when it isn't. Balcony power plants do a very good job of educating and motivating people to do this.
hagbard_c 2y ago
Don't give energy away to the operator, they don't (want to) give you energy for free either. Get something which can soak up excess energy - a battery, an electric water heater, whatever - and run that on whatever excess energy you have. Assuming you don't invest too much money in such a project you'll end up saving a bit more money and you'll avoid being fined for pushing energy into an already overloaded network once everyone and his dog have installed solar which pushes up the voltage from nominal 230VAC to somewhere around 245-250VAC (250VAC is the usual cutoff for inverters where I live (Sweden)). I installed 14.5 kW of PV panels on the barn roof a few years ago and hooked them up to a 10 kW hybrid inverter. Hybrid inverters can divert energy (from the PV panels or from the net) to a battery which can be used at a later stage to feed consumers in the local installation or to backfeed to the net. Since we currently have a contract which allows us to sell energy at market rates we do not have a battery yet but I don't know yet what the next contract (in 2 years) will look like. Assuming that we can no longer sell at market rates I'll install around 60-80 kWh in battery capacity to soak up excess production and dump the rest in the water heater etc. If we ever get a hybrid or electric car/tractor/whatever I'll add battery capacity so as to be able to charge those with excess energy. By that time we'll be close to ready to go off-grid which is fine by me, electricity prices here in Sweden have skyrocketed due to the demand from (mostly) Germany for excess capacity since you shut down your nuclear power plants. The more transmission capacity is built in the Baltic, the higher our prices get.

starlite-5008 2y ago

[dead]

deleted 2y ago

[deleted]

jnsie 2y ago

Live in an apartment in NYC and would love some way of turning our windows into solar panels. They only thing I've seen is a ~$100 device from a company called grouphug (no affiliation) whereby a small solar panel is stuck to a window via suction cup and can charge a phone (I believe it has a small in-built battery). Laudable but I wonder if it would return the investment.

Gasp0de 2y ago
It won't. These systems are quite large (a single solar panel is approximately 1.2m by 1.7m (4 to 6 ft ?) and even if you put it outside with direct southern exposure and no shade it takes 2-5 years to recoup the investment cost. In the US, you pay less for electricity (in most places) so it would take longer. Behind a window, generated energy will be way less.

TacticalCoder 2y ago

A friend of mine put solar panels on the roof of his house in France. He's got a 42U rack with shitloads of servers / more than 200 TB of disks / several 4090 GPUsrendering AI stuff etc., quite the beefy setup and yet at times, on certain days and for a few hours, the solar panel are powering it all (not just the 42U rack but the entire house, including the HVAC). Quite nice.

xnx 2y ago

This seems about the perfect energy technology: affordable, self install, clear ROI, no permits necessary, no distorting subsidies.