> And don't let perfect be the enemy of good. Yes there are times when solar doesn't produce energy, but there are also times where it OVERproduces.
When solar OVERproduces you have to literally pay someone to consume that energy, most probably wind farms, which could be producing energy instead. So you pay actually twice. When the solar underproduces, you need to bring in alternative sources, but those now have to cover all their fixed costs and generate return on investment over this limited timeframe, which means the actual backup prices hit stratospheric levels.
What's the actual cost of solar with actual net-billing?
I'm every day more convinced that the only reasonable future of energy production is distributed solar and storage with microgrids at the neighbourhood level or so.
Anything bigger in scale is prone to being shittified to the limit by public entities.
Rooftop solar is incredibly popular here in Australia. I think it’s something like 33% of houses have it. We also have a great climate for it.
I have solar on my house and am seeing around 50% self sufficiency overall. Of course with this much saturation, the rate you get paid for feeding back to the grid is quickly dropping to zero. So self use is the game now.
The problem is now shifting to home batteries and storage. Because peak power household use times are in the evening when the sun is not shining.
The UK previously didn't allow small plug in solar panels (the kind that you just plug in to a mains socket) due to, I believe, safety reasons. This has changed within the last few days https://energysavingtrust.org.uk/solar-roadmap/
I believe it’s only legal in Utah so far in the US: they legislated it last year, and apparently half the country is expected to pass a copy-paste version in their next sessions
There is a real safety issue with plug-in solar panels and plug-in batteries. Things go wrong if other loads are on the same circuit, which is almost unavoidable with a plug-in system.
Consider a circuit in a home, designed to carry 16A like a common EU/UK circuit, protected by a 16A breaker. Then plug in solar or a battery that delivers just a small 10A. Now in case some other thing on that circuit draws 26A, the breaker doesn't stop it and the circuit is overloaded.
If that same solar was installed as a fixed setup on its own circuit with no other loads on it, it would be safe and protected by the 16A breaker in the switchboard. It's the combination with other loads that causes issues.
My understanding is that is why they are limiting to 800w (~4A) at least in the UK's BS 7671 Amendment, which they consider well within the designed safety margins.
So the danger comes when you plug the solar into a wall socket but there are other devices connected to the same fuse of circuit breaker. So...
Instead of the solar having a plug that goes into a wall socket, why not have a plug on it that screws directly into the fusebox ? Then you know that it is the ONLY device on the circuit.
"Many consumers want to know how long it will take them to make back the upfront costs of solar"
my answer is that the payback is imediate, right from the first moment watching as energy is generated out of thin air, and the sudden relief from getting off the energy angst missery-go-round, and the sheer borring inertness of solar pv as it does the thing with zero detectable effort, is gratifying and relaxing in a way that money never gives.
I will add that solar pv is increadably robust, and damage tollerant as well, you can drive a claw hammer through a panel, and while it does not improve the performance, the degradation is actualy not that much, and it will continue to function for years
The mindset shift towards “how many hours of computer usage did that one panel enable” is like the mindset shift from learning calculus, in some ways. Not quite a paradigm shift, but you gain a new appreciation for conservation of use when it’s a difference between choice of $/kW/hr and “wow, the panel powered that for most of the day”.
At the same time, many people will just use a solar calculator or watch or yard lights etc, oblivious to it all.
Show people a solar powered laptop, a solar powered phone, or a solar powered tablet, then they will be impressed.
Remember the craze about solar powered car competitions?
permacompute + solar would make for quite the $100 laptop competition.
Is it immediate? Sure, there is satisfaction that you are using 'free' electricity. But it does have an upfront cost. I calculated that it would take over 11 years to recoup the investment based on our current usage. Given we already get cheap night-time rates to charge the car and run appliances, it is hard to justify.
Like many UK houses, we have gas central heating too. I guess if we had a battery too (more investment) then we could switch to using electric oil-filled radiators, though they would not heat the whole house. And we could install a hot water tank.
I guess for new builds there is a real opportunity, but for an existing household I'm struggling to see how it works - and I want it to!
>> "Many consumers want to know how long it will take them to make back the upfront costs of solar"
> my answer is that the payback is imediate,
So if I pay $35k for an install, I get a $35k check the first time I connect it to the grid? Pretty sure it doesn't work that way. But it would be a nice subsidy from the government if they were really motivated.
I guess you're saying you start to feel good and validated to have spent the money by seeing _some_ savings every billing period. It's hard to argue with feelings of course, but that's not not the original concern. People want to know how long is it going to take: 1, 5, 10 years or ... never (if panels degrade or break before it will never pay off) to pay off their investment.
We just got solar panels and a battery installed on our house. I try to be hard-headed about the economics when planning, but I have to say the _experience_ of having done it is exactly as you describe.
The other thing it made me is angry at the political morass that these things seem to be in.
At a technical level I understand the ‘base load’ arguments, but we are throwing away _so much energy_ that’s just there for the taking by not having these everywhere. On most days, our house (in Western North Carolina) gets enough energy from the sun that we net-export to the grid - and we have an EV! There’s just no need for the massive amounts of carbon we are spewing into the air - the energy is just falling onto us!
In the future, providing we’re still around, we’ll look back at a time when we could’ve been getting all our energy needs from just the sun (and wind etc.) and shake our heads in disbelief at those who fought against the idea that we should even think about efficiently using it so viscerally.
It’s already possible for consumers to know that, I worked on the software that powers the tools that tell US consumers this at Genability ca 2015.
As far as I know, they never cracked the European market, so if you’re interested in working on that, I’m currently available for hire! Info in profile :)
I once read an article that in Berlin the sewage system is flushed with fresh water because too many people have installed water saving toilet flushers. So plenty of people bought these water savers and now the price of water has gone up because the water that is directly flushed needs to be paid too.
The 'balcony power stations' are the same thing. They get subsidised, and you even get a fixed kWh price when pushing into the grid.
The problem is that in the end it will become more expensive for everybody because at times you have a surplus driving the whole sale electricity prices into the negative while still paying fixed prices for injection into the grid.
To make this economically viable, you have to have everyone paying spot prices. Everything else is just green ideology driven inefficiency.
Just to make it clear, I think renewables are an important option for the future. But to make them a viable option of the electricity energy mix, supply and demand, storage and grid capacity need to be taken into account.
Last not least, there is plenty of low hanging fruit to drive CO2 emissions down: drive up the truck tolls. Currently you have potatoes farmed in Germany, driven to Poland to get washed, transported to Italy to be converted to french fries and transferred back to Germany into the super markets.
Same goes for home office, during Covid it was possible for many workers to continue with their work. Does an accountant need to drive to an office every day? Nope. How many business trips could be replaced by a video call?
If the CO2 emissions problem is to be solved rather sooner than later, the money has to be spend efficiently as there isn't enough of it.
As soon as everybody is paying spot prices, balcony power stations are not economically viable anymore. Even today, on a sunny day, spot prices for electricity are either very low or even negative. The more solar power is available, the lower these prices will be. So your balcony power station is replacing electricity you could get for free anyway. At night, when you are not producing electricity, you still need to buy the expensive electricity from fossil plants.
The reason why personal solar installations are profitable is that you can buy electricity for fixed prices from your local power company. You pay the average of the vastly different low (or negative) prices during the day and the extremely expensive prices on windstill nights. Solar allows you to use your own electricity when the average is below spot prices, and get power for much less when the price you pay is cheaper than spot prices. It's like a state-approved scheme to play the market in the name of decarbonization while actually increasing everybody else's prices and possibly even CO2 emissions.
The price of water has gone up for a multitude of factors. One of them is water savings in general, but not primarily because the sewage system requires regular flushes. The reason is that water gets paid per qubic meter and includes a fresh water and a waster water component. The assumption is that almost all fresh water you use ends up as waste water. Now, the grid has a very substantial fixed-price component that's largely independent from the actual current volume being used. Putting pipes in the ground and maintaining them there is an actual costly endeavour. If water use now drops, and the baseline cost remains stable, then it's entirely expected that the price per volume rises. It's simple math. The same baseline cost needs to be brought in via less volume.
This will also happen to people that use residential gas. As less and less people use residential gas, the maintenance of the gas network gets distributed among less and less customers.
> The 'balcony power stations' are the same thing. They get subsidised, and you even get a fixed kWh price when pushing into the grid.
They are subsidized on purchase, but the price they get when pushing energy into the grid is by default fixed at 0. The network accepts the power, but there's no payment. It's also capped at 800W delivery, meaning that at peak power generation, you'd earn a whopping 5 cent an hour with the current subsidy for full scale solar power. So in practice, the only benefit owners have is that they draw less power from the net which is much more attractive because of the pricing structure. You can, optionally, register your balcony power station as a regular solar power plant, but then you're subject to a whole bunch of rules and regulations (for example you need a suitable elctricity meter etc.). This option is generally not attractive for such small power generations.
Fundamentally, though, the same issue as with the water and gas network exists with all localized (solar) power generation. If more and more people use the grid only as a backup, or for winter energy needs, then the overhead of maintaining the grid will have a larger cost contribution to the total cost of electricity.
And exactly as soon as your prediction comes true, it will become obvious for people to buy battery banks that perform temporal arbitrage. Which will then mostly solve the issue.
(I note that in the alternate universe where Ed Miliband became PM because he didn't eat a bacon sandwich, we could have had this a decade ago. It is embarrassing to be beaten on environmentalist regulatory efficiency by Germany)
> I note that in the alternate universe where Ed Miliband became PM because he didn't eat a bacon sandwich, we could have had this a decade ago
I read what is happening in exactly the opposite way. To me it shows that Milliand and the government at large do very little with no strategic thinking and no plan (same as the guys before in fairness but this government was supposed to be soo different...) and, in this case, is only reacting in a panic after almost 2 years in office to the pressure of "doing something" because of the Iran war, while also being told (slight mitigating circumstances for Milliband) that it mustn't cost anything. I always picture scenes from The Thick of It/ In the Loop when I imagine how they come up with 'ideas'.
I find it fascinating how this comment comes up with a whole theory of what happened, along with implications about how the government, and Ed Miliband in particular, think and act, and it’s based entirely on just dreaming up what the facts are, when in reality the facts can be looked up trivially, including the fact that this was in the manifesto, or other facts that are known by anyone who has any knowledge about how govt (especially the UK govt that is designed to be conservative and slow moving) works.
Like you just invented a story and made massive implications based on the invented story, with absolutely no hesitation. And you’re probably in at least the 50th percentile of intelligence.
He also removed the effective ban on onshore wind construction that was introduced a month after he lost the election, restarting after a decade of lost opportunity.
This Trump-level idiocy that is just never mentioned, even as people blame the gas burned in england on windy days as a cost of wind curtailment, when the curtailment is more a like a third of the cost. Burning gas to power people who chose not to build turbines is the other 2/3rds.
In the alternate world that is tens of billions of gas costs avoided to date and tens of billions more in future.
I always blew my mind that people don't mention this more. The UK is blessed with some of the most plentiful and reliable wind resources on earth, and mediocre solar resources at best.
Banning onshore wind turbines was just insanity. Despite the insanity, the UK has made great steps with offshore wind, but offshore wind is expensive and has all sorts of accompanying headaches. Onshore is super cheap and quick to build per unit power by comparison.
Onshore wind turbines are going to be much more important to the future of UK energy independence than balcony solar.
British industry and standards bodies think this is an unsafe plan.
Of course they would because it's work being taken away from them but it would be allowing people to plug generators into ring finals with unidirectional breakers. It's not even guaranteed that the circuit is protected by anything newer than fuse wire or an MCB. No guaranteed earth leakage detection. No guaranteed surge protection. Relying on the cheapest inverters to sync frequency accurately. And
I have more faith in German standards and work ethic than our own.
In the US, Utah has allowed balcony solar since May 2025 and Virginia is expected to allow it starting in January 2027 (awaiting the governor's signature).
Can anybody explain how these plug-in solar panels work? I am suprised that it's possible to just plug them in to your wall socket.
For instance, isn't it complicated to have their output be in perfect sync with the frequency that comes in via the electricity net? Because to me it seems that if they won't, you will have lower benefits or even a net minus after plugging it in.
"Suddenly" is horrific evidence that the government has no idea how to do long-term plans.
Wait until you tell them you can run cars entirely on electricity from a solar farming. I'm sure they will ignore you until the price of diesel reaches four-digit territory. 1000p today? If only we didn't have to pay these incredible prices, what a miracle that would be..
For european individuals, yes. For european nations, not in the least. They try to avoid independent consumers and producers of energy with all the regulations they can throw to them.
Several recent HN posts about "time" and these correlate superbly in relation to the now obvious, to nearly all, global energy issues. Those proactive in a reactive world are often mocked and laughed at until as such passage of time is achieved for those only reactive to learn of the proactive's hindsight choices. For those in the United States aware of the 'behind the scenes' energy grid issues this insight reflects that prices will not be dropping for those electrons we all so depressively require daily just like our air and water. Energy grid decentralization is occurring with the actions of each individual and this article supports exactly that because no one alive can survive in our modern world without those electrons. "Necessity is the mother of invention" only now resonates for some while the futurists here that acted long ago acutely understand this growing trend.
i have been looking on this for an year+.. Here some current (online-shops) prices in Bulgaria.. say shop.chepakov.com / kameasolar.com
- panel 490Wp 2sq.m chinese = ~80E
- battery 5kwh Li chinese = ~1200E , non-chinese ~2000E+
- hybrid invertor+charger 4kw = ~800E chinese , ~2000E non-chinese
- grid and regulations:
-- day price: 0.15E/kWh, night: 0.09E/kWh
-- no such thing as spot prices - summer or winter, peak sun or midnight, no difference
-- can install anything AS LONG AS Nothing goes back into grid - and does not break other city/dwelling rules
if one gets the electronics from Germany - geizheis.de - prices are half, coz a) no VAT, b) less middlemen . Even some smaller things come with free postage - from Germany to Bulgaria ; i did buy several smaller chargers/inverters (5kg), while local sellers here have no such ideas. But anyway.
The (proven) efficiency one can get is about 50-60% per Wp (if there is sun). So.. it depends how much panels one can install as that is the monie-source, all else is monie-sink :/
Rough Napkin math, electronics with german prices, ~5 hours per day sun on average: 10 panels (1000E) + 2 batteries (2000E) + inverter (1000E) ~~4000E yielding on average 440kwh/month i.e. pay itself in 5-7+ years, mostly for summer loads. While 5 panels + 1 battery + inverter ~2500E -> ~220kwh/month -> 6-8+ years
BUT only IF you can use that much electricity, otherwise it will take much longer to repay. And, batteries have to be replaced probably in 5-7 years, depending on depth-of-discharge.
In most places here everything is electrical. i have convectors, boilers, stove, etc. No A/C. (all other electrics is maybe under 2kw in total). i use like day/night 400/250kWh in summer, 1400/800 kWh in winter. Some people have noisy heat pumps but doubt that changes things much.
If it was a separate house - i would have done it long ago. But it's a block of flats.
So... small Balcony stuff makes no sense (a very expensive UPS?), big balcony stuff (like putting those 5 panels as balcony's shade.. a) probably won't be allowed, b) only a short balcony faces south-ish.
The roof of the building is empty - 250sq.m - and can hold about 75 panels - but dividing that into 15 (or 50+ in higher buildings).. is not pretty. a) Making one single farm and splitting the bill/output seems the only reasonable way but does not work without completely rewiring the building's grid input and measurings; not doable without bunch of permissions/certifications ; while b) making 15 separate 5-panels-packs - is not much economical, plus few kilometers of cables.. And c) If only few people want panels on roof, maybe some form of renting the roof space from others who don't want.. may work for a while but as any renting, may go crazy.
So.. been sitting and thinking.. and recently seems only sitting..
In the US, Distribution costs (the separate charge outside of your energy cost on your utility bill) are also incredibly high and going to keep rising as infrastructure costs mount. In my area, my distribution costs is actually more than my energy cost so the only way I ever think about solar is if I can decouple from the grid completely and get rid of those distribution costs. Got a long lo no ways to go
Practical...if you ignore hot water. Once you add that into the mix, you either need a lot of space for a large hot water tank, or a very big battery. Peak charges make tankless resistive water heaters very expensive to run.
Heck, I don't even have anywhere to place a heatpump, let alone a hot water tank.
I live in Germany, installed a micro solar system in September 2024. Since then, we've been producing 45% of our electricity consumption ourselves. This has saved us 550€, while the initial cost was around 800€. So this September, after 2 years, the system will have paid for itself.
60 comments
[ 3.4 ms ] story [ 65.7 ms ] threadEvery solar farm doesn't need to be China Size - it doesn't even need to be a "farm", just put them on roofs.
And don't let perfect be the enemy of good. Yes there are times when solar doesn't produce energy, but there are also times where it OVERproduces.
When solar OVERproduces you have to literally pay someone to consume that energy, most probably wind farms, which could be producing energy instead. So you pay actually twice. When the solar underproduces, you need to bring in alternative sources, but those now have to cover all their fixed costs and generate return on investment over this limited timeframe, which means the actual backup prices hit stratospheric levels.
What's the actual cost of solar with actual net-billing?
Anything bigger in scale is prone to being shittified to the limit by public entities.
I have solar on my house and am seeing around 50% self sufficiency overall. Of course with this much saturation, the rate you get paid for feeding back to the grid is quickly dropping to zero. So self use is the game now.
The problem is now shifting to home batteries and storage. Because peak power household use times are in the evening when the sun is not shining.
Consider a circuit in a home, designed to carry 16A like a common EU/UK circuit, protected by a 16A breaker. Then plug in solar or a battery that delivers just a small 10A. Now in case some other thing on that circuit draws 26A, the breaker doesn't stop it and the circuit is overloaded.
If that same solar was installed as a fixed setup on its own circuit with no other loads on it, it would be safe and protected by the 16A breaker in the switchboard. It's the combination with other loads that causes issues.
Instead of the solar having a plug that goes into a wall socket, why not have a plug on it that screws directly into the fusebox ? Then you know that it is the ONLY device on the circuit.
"Many consumers want to know how long it will take them to make back the upfront costs of solar"
my answer is that the payback is imediate, right from the first moment watching as energy is generated out of thin air, and the sudden relief from getting off the energy angst missery-go-round, and the sheer borring inertness of solar pv as it does the thing with zero detectable effort, is gratifying and relaxing in a way that money never gives.
I will add that solar pv is increadably robust, and damage tollerant as well, you can drive a claw hammer through a panel, and while it does not improve the performance, the degradation is actualy not that much, and it will continue to function for years
At the same time, many people will just use a solar calculator or watch or yard lights etc, oblivious to it all.
Show people a solar powered laptop, a solar powered phone, or a solar powered tablet, then they will be impressed.
Remember the craze about solar powered car competitions?
permacompute + solar would make for quite the $100 laptop competition.
Like many UK houses, we have gas central heating too. I guess if we had a battery too (more investment) then we could switch to using electric oil-filled radiators, though they would not heat the whole house. And we could install a hot water tank.
I guess for new builds there is a real opportunity, but for an existing household I'm struggling to see how it works - and I want it to!
> my answer is that the payback is imediate,
So if I pay $35k for an install, I get a $35k check the first time I connect it to the grid? Pretty sure it doesn't work that way. But it would be a nice subsidy from the government if they were really motivated.
I guess you're saying you start to feel good and validated to have spent the money by seeing _some_ savings every billing period. It's hard to argue with feelings of course, but that's not not the original concern. People want to know how long is it going to take: 1, 5, 10 years or ... never (if panels degrade or break before it will never pay off) to pay off their investment.
The other thing it made me is angry at the political morass that these things seem to be in.
At a technical level I understand the ‘base load’ arguments, but we are throwing away _so much energy_ that’s just there for the taking by not having these everywhere. On most days, our house (in Western North Carolina) gets enough energy from the sun that we net-export to the grid - and we have an EV! There’s just no need for the massive amounts of carbon we are spewing into the air - the energy is just falling onto us!
In the future, providing we’re still around, we’ll look back at a time when we could’ve been getting all our energy needs from just the sun (and wind etc.) and shake our heads in disbelief at those who fought against the idea that we should even think about efficiently using it so viscerally.
As far as I know, they never cracked the European market, so if you’re interested in working on that, I’m currently available for hire! Info in profile :)
The 'balcony power stations' are the same thing. They get subsidised, and you even get a fixed kWh price when pushing into the grid.
The problem is that in the end it will become more expensive for everybody because at times you have a surplus driving the whole sale electricity prices into the negative while still paying fixed prices for injection into the grid.
To make this economically viable, you have to have everyone paying spot prices. Everything else is just green ideology driven inefficiency.
Just to make it clear, I think renewables are an important option for the future. But to make them a viable option of the electricity energy mix, supply and demand, storage and grid capacity need to be taken into account.
Last not least, there is plenty of low hanging fruit to drive CO2 emissions down: drive up the truck tolls. Currently you have potatoes farmed in Germany, driven to Poland to get washed, transported to Italy to be converted to french fries and transferred back to Germany into the super markets.
Same goes for home office, during Covid it was possible for many workers to continue with their work. Does an accountant need to drive to an office every day? Nope. How many business trips could be replaced by a video call?
If the CO2 emissions problem is to be solved rather sooner than later, the money has to be spend efficiently as there isn't enough of it.
The reason why personal solar installations are profitable is that you can buy electricity for fixed prices from your local power company. You pay the average of the vastly different low (or negative) prices during the day and the extremely expensive prices on windstill nights. Solar allows you to use your own electricity when the average is below spot prices, and get power for much less when the price you pay is cheaper than spot prices. It's like a state-approved scheme to play the market in the name of decarbonization while actually increasing everybody else's prices and possibly even CO2 emissions.
This will also happen to people that use residential gas. As less and less people use residential gas, the maintenance of the gas network gets distributed among less and less customers.
> The 'balcony power stations' are the same thing. They get subsidised, and you even get a fixed kWh price when pushing into the grid.
They are subsidized on purchase, but the price they get when pushing energy into the grid is by default fixed at 0. The network accepts the power, but there's no payment. It's also capped at 800W delivery, meaning that at peak power generation, you'd earn a whopping 5 cent an hour with the current subsidy for full scale solar power. So in practice, the only benefit owners have is that they draw less power from the net which is much more attractive because of the pricing structure. You can, optionally, register your balcony power station as a regular solar power plant, but then you're subject to a whole bunch of rules and regulations (for example you need a suitable elctricity meter etc.). This option is generally not attractive for such small power generations.
Fundamentally, though, the same issue as with the water and gas network exists with all localized (solar) power generation. If more and more people use the grid only as a backup, or for winter energy needs, then the overhead of maintaining the grid will have a larger cost contribution to the total cost of electricity.
Government press release with a long list of pull quotes: https://www.gov.uk/government/news/government-to-make-plug-i...
(I note that in the alternate universe where Ed Miliband became PM because he didn't eat a bacon sandwich, we could have had this a decade ago. It is embarrassing to be beaten on environmentalist regulatory efficiency by Germany)
I read what is happening in exactly the opposite way. To me it shows that Milliand and the government at large do very little with no strategic thinking and no plan (same as the guys before in fairness but this government was supposed to be soo different...) and, in this case, is only reacting in a panic after almost 2 years in office to the pressure of "doing something" because of the Iran war, while also being told (slight mitigating circumstances for Milliband) that it mustn't cost anything. I always picture scenes from The Thick of It/ In the Loop when I imagine how they come up with 'ideas'.
Like you just invented a story and made massive implications based on the invented story, with absolutely no hesitation. And you’re probably in at least the 50th percentile of intelligence.
This is why we’re screwed.
This Trump-level idiocy that is just never mentioned, even as people blame the gas burned in england on windy days as a cost of wind curtailment, when the curtailment is more a like a third of the cost. Burning gas to power people who chose not to build turbines is the other 2/3rds.
In the alternate world that is tens of billions of gas costs avoided to date and tens of billions more in future.
Banning onshore wind turbines was just insanity. Despite the insanity, the UK has made great steps with offshore wind, but offshore wind is expensive and has all sorts of accompanying headaches. Onshore is super cheap and quick to build per unit power by comparison.
Onshore wind turbines are going to be much more important to the future of UK energy independence than balcony solar.
Of course they would because it's work being taken away from them but it would be allowing people to plug generators into ring finals with unidirectional breakers. It's not even guaranteed that the circuit is protected by anything newer than fuse wire or an MCB. No guaranteed earth leakage detection. No guaranteed surge protection. Relying on the cheapest inverters to sync frequency accurately. And
I have more faith in German standards and work ethic than our own.
What do you mean by "guaranteed surge protection"? Are you an electrician to write like that?
And it is of course home-counties obsessed thinking. They can both afford these toys and also have more sun
For instance, isn't it complicated to have their output be in perfect sync with the frequency that comes in via the electricity net? Because to me it seems that if they won't, you will have lower benefits or even a net minus after plugging it in.
https://www.swissinfo.ch/eng/climate-adaptation/switzerland-...
Wait until you tell them you can run cars entirely on electricity from a solar farming. I'm sure they will ignore you until the price of diesel reaches four-digit territory. 1000p today? If only we didn't have to pay these incredible prices, what a miracle that would be..
The (proven) efficiency one can get is about 50-60% per Wp (if there is sun). So.. it depends how much panels one can install as that is the monie-source, all else is monie-sink :/
Rough Napkin math, electronics with german prices, ~5 hours per day sun on average: 10 panels (1000E) + 2 batteries (2000E) + inverter (1000E) ~~4000E yielding on average 440kwh/month i.e. pay itself in 5-7+ years, mostly for summer loads. While 5 panels + 1 battery + inverter ~2500E -> ~220kwh/month -> 6-8+ years
BUT only IF you can use that much electricity, otherwise it will take much longer to repay. And, batteries have to be replaced probably in 5-7 years, depending on depth-of-discharge.
In most places here everything is electrical. i have convectors, boilers, stove, etc. No A/C. (all other electrics is maybe under 2kw in total). i use like day/night 400/250kWh in summer, 1400/800 kWh in winter. Some people have noisy heat pumps but doubt that changes things much.
If it was a separate house - i would have done it long ago. But it's a block of flats.
So... small Balcony stuff makes no sense (a very expensive UPS?), big balcony stuff (like putting those 5 panels as balcony's shade.. a) probably won't be allowed, b) only a short balcony faces south-ish.
The roof of the building is empty - 250sq.m - and can hold about 75 panels - but dividing that into 15 (or 50+ in higher buildings).. is not pretty. a) Making one single farm and splitting the bill/output seems the only reasonable way but does not work without completely rewiring the building's grid input and measurings; not doable without bunch of permissions/certifications ; while b) making 15 separate 5-panels-packs - is not much economical, plus few kilometers of cables.. And c) If only few people want panels on roof, maybe some form of renting the roof space from others who don't want.. may work for a while but as any renting, may go crazy.
So.. been sitting and thinking.. and recently seems only sitting..
America - "I'mma roll coal and scream about birds and windmills."
Heck, I don't even have anywhere to place a heatpump, let alone a hot water tank.