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Comment by harmmonica | Hacker News Reader

Question for those in the know... See lots of press about balcony solar in Germany, and California recently introduced a bill to allow it (I'm guessing other states already allow it; not sure if the CA bill has a chance of becoming law). But how far are we from a more plug and play home solar system that becomes a primary energy source as opposed to a limited secondary source? And what are the issues with it actually becoming a reality? Is it primarily regulatory where government, utilities, installers would fight it tooth and nail to protect revenue and/or the grid? Is it a legit safety issue? I have to imagine safety could be easily addressed in terms of the power management between grid and solar (obviously these balcony units are relatively safe, but tiny in comparison). Installation perhaps has more safety issues (e.g., installing panels on a roof), but I just wonder if it's reasonable to think that a more robust plug and play option will become available or is even already available in certain places.

And I feel the need to say this, but this is the type of question I'd immediately turn to an LLM to answer, and I probably will ultimately, but I "still" like getting peoples' on-the-ground experience/expertise.

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It can't be more or much more than the 800W as currently done in Germany because it would not be safe with the way electricity is delivered to a home.

The reason is: when you pull electricity from the grid, the fuse would blow if you tried to pull too much current (e.g. you connect four hair dryers on the same outlet). It blows to prevent the wiring in your home from overheating and catching on fire. With balcony solar, you plug it in your home outlet which is already behind the fuse, which means the fuse cannot react and cut off power if you try to feed in more than the capacity allows. You could be maxing out on the current you are pulling from the grid, and then on top of that you would be adding your balcony solar.

Why it's allowed at all in Germany and other places is because the fuse will blow above 10A and the wiring in the house is 16A, so there was always a buffer or overcapacity in the wiring, presumably just in case. So they allowed 800W of balcony solar which is roughly 3.5A and still there is some wiggle room left.

Also why pull from the grid at all: your appliances actually just use the electricity from the grid. In Germany and I guess most of Europe they run a three phase system, so your balcony solar might not be in the same physical circuit as your appliances in use. With balcony solar your meter just offsets your consumption with whatever you are feeding it at the moment. From the grid standpoint if you are running something using 800W and feeding in 800W, it's 0.

Of course it can work without this too, but this defeats the purpose of balcony solar, which is plug it in and it works simplicity.

This is very interesting and helpful info! I guess my fantasy is that a standard electrical panel would eventually have a literal plug on it where you could plug a larger system in, just as you would an outlet in the balcony situation, and then it would I think be, using your word, in "front" of the "fuse" (using quotes because I'm not sure I have the behind/in front of language correct, and when you use fuse here in the states it would be a breaker, I guess, not an actual fuse). This solution would of course have to mitigate things like fire risk, or blowing up the house or grid itself. I'm just hopeful it's coming because I think the install rate would go through the, pardon me, roof.

The post you replied to isn't fully correct. I'll tell you how you could do this in many ways that prevents the fuse problem.

There's 3 ways to run solar.

Grid tied, grid backed and off grid.

I live on a farm and am off grid. The solar inverter is my "utility". After the inverter I have my main breaker. The inverter makes 5 kW max at 230 volts, so my fuse is 5000/230 = 20 amps.

I'm outside the US, regulation is a suggestion here everyone ignores. So many many houses have solar panels here to offset grid costs ($0.60 per kWh).

The main way we do it is make it grid backed. This means the inverter creates power that is in no way mixed with grid power. It forms a microgrid within the home. All ac's are connected to this. This can be done in the electrical panel as its just rerouting wires to fuses.

So then you have your 20A fuse behind the inverter, and smaller fuses (which you should already have) to your house loads. Btw you guys run 110v so your fuses are probably double the rating of ours.

When you do grid backed a battery is nice, since it helps prevent using the grid when a cloud passes by, it forms a bit of buffer. A 5kWh battery already helps. At night the grid powers the loads.

Grid-tied is the one nobody here uses, so you can feed back to the grid. This involves complicated electrical stuff so you don't electrocute the line workers. Plus it gets complicated with split phases and such.

Not to mention utilities pay less than what they ask you for the same kWh.

In the case of balcony solar you can feed the inverter utility power and connect your AC to the inverter. It uses solar power first and takes the needed diff from utility.

Know you don't want to dox yourself, but .6 is... rough. Like super rough. Would love to know where this is, but no pressure. Thankfully you're not relying on it completely. And oh what I wouldn't give to know the incidence of deadly maybe very-damaging electrical fires there given your well put "regulation is a suggestion here everyone ignores." Because if the incident rate is no worse than here you can make some assumptions that the regulations here are overly burdensome. I'd be remiss if I didn't say that regulations are oftentimes written in blood; it's true in the case of electrical generation, distribution, installation, but it's also a glib way to stand in the way of solutions that improve peoples' lives.

I think it's the reason why we ignore regulation. It's not really malice or greed, local government is just a mess. It takes months of waiting.

And when we "break the rules" we consider the rules and break them in a way that minimizes our liability.

Like the reason for the certified install is to protect the line workers. I live on an island, so that's basically my neighbours. Nobody wants them dead. Likewise nobody wants to go through bureaucratic hell.

Solution: grid-backed installs that doesn't interact with the grid. Which any Juan or Pedro can do if you don't want to do it yourself. It runs around $200 to add a new "electric group" to your house.

And to be fair the standard rate is 0.38 cents per kWh and some fixed rate. But the poor they force on the pre-paid package which has no fixed rate, but runs at that higher rate.

And so when you can't afford to buy the electricity you end up in the dark without giving the utility any moral obligations.

I live in the "Caribbean Netherlands", the largest island of the 3.

Worth noting that in the US mains is split phase so we get in 240 V with 2 supply lines (large appliances can use 240 V) that give us 2 120 V lines

I imagine it could be done like thus, but it is not, there's no infrastructure like this, so it's a moot point. Balcony solar was allowed so it's a hassle free DIY solution. You also don't get any money for feeding into the grid, but because you save a lot of money on installation costs it's still worth it.

Another limitation is the transport capacity of each power line and each transformer (power lines and transformers don't care for the direction of the electricity, only for the amount of electricity).

For example if each house in a city would have 25A fuse and all the houses would simultaneously draw 25A, or simultaneously supply 25A the grid would collapse.

Usually the Diversity Factor for apartment block electric grids is around 35%.

https://www.geeksforgeeks.org/electrical-engineering/diversi...

https://ecalpro.com/compare/demand-diversity-100-apartments

i think it’s kind of the opposite: balcony solar is good for power companies in the same way that them asking you to turn off your lights is good for power companies: if each customer is using less overall power they can serve more customers with existing infra.

that obviously depends on time of use and the sun etc, but balcony solar in the USA can’t come fast enough. my electricity in NYC is almost $.40/kWh, a limited secondary source is still huge

it makes a lot of sense to me as someone who has casually researched as a way to make the load of an A/C vanish from the perspective of my utility, but i can’t see regulations catching up nationwide soon.

any real microinverters can detect the grid being down and shut off to prevent zapping people working on power lines, but the complexities of split-phase power (you can consume on one leg but backfeed on the other leg rather than consume what you generate, which is bad for billing etc) and risks of intra-circuit overload will all freak out americans.

we put outlets absolutely everywhere because of how scared we are of extension cords, there’s an education and “am i going to start an electrical file” consumer sentiment obstacle to widespread adoption in the US

Have you seen this? Free battery in NYC if you charge it with off-peak power

https://everyelectric.com/

i think that is an overly simplistic axiom: the utilities must cover a fixed asset base (poles and wires and transformers), pretty much regardless of how much or whether a household consumes from the grid.

the less the utility recoups via billing for energy usage, the bigger the deficit to cover their fixed network costs.

they are frequently interested in having you consume energy, to help defray those costs, especially where the marginal cost of the energy is very low.

the more users who disconnect, the more the fixed costs must be recouped from a shrinking customer base, triggering more incentive to leave the network. this is called the death spiral.

In addition, things like balcony solar don't save them cost: it introduces complexity because they need to safely manage that load, they need to be able to predict and measure it; in my experience working with utilities and network operators for many years, they flat out don't want these distributed generation sources unless they have a lot of say in how they are added to the grid, and how users can be charged for the privilege of generating their own power. that is often a very significant barrier to regulatory change.

that’s true, i was considering only the perspective of the major city i live in rather than networks with lower ratepayer densities where the economics are probably totally different

i do think “fully consumed or gated to never backfeed balcony solar at scale” is all i’m referring to, which i naively hope is a smaller regulatory change than backfeeding

Everything I have seen about balcony solar requires it to be grid dependent and cannot backfeed.

> I do think “fully consumed or gated to never backfeed balcony solar at scale” is all i’m referring to, which i naively hope is a smaller regulatory change than backfeeding

I though the point of these systems was you plug them in to your wall socket and they lower your electricity bill. If you want to avoid tieing to the grid you can't have such a simple deployment.

That definitely sounds reasonable for balcony, but I was trying to ask if you were able to generate the lion's share of your usage from a DIY or plug and play system would the utilities be against that? I would think so because that would eat into their profits. If enough people were knocking several cents per kWh off their bills, would they just end up charging more for the infrastructure to make up for the loss? I'm sure there's some happy medium where they'd be happy, as you say, but at some number I'm guessing they'd fight back against too much adoption.

> my electricity in NYC is almost $.40/kWh, a limited secondary source is still huge

This alone would be incredible from wider adoption of balcony (incredible for the consumer I mean). If you knock a few cents per kWh off, which I think you can do with daytime/early evening usage (when the panels are still producing some energy so no storage required) that would be fantastic. Baby steps to a full system that you can DIY without anyone objecting.

Yes. The utilities want every household to pay them every month.

Here in California, PG&E has a "base service fee" of $24/month. That you owe even if they sell you no (as in ZERO) electricity:

https://www.pge.com/en/account/billing-and-assistance/base-s...

Yep, totally, and I'd personally be overjoyed if I could pay PG&E (hypothetically; they're not my utility) $24/month to keep the grid afloat, but no more than that because I'm producing all I need locally (at the risk of repeating myself, I know this is possible today. Just hopeful that over time it becomes possible to do that install in a plug and play fashion just like you can do with the balcony solar, but at whole-house scale (or at least some material fraction of the whole house usage)).

Seems reasonable if you want to be connected to it.

The grid costs a significant amount of money to build and maintain, and maintaining the available capacity to serve you electricity even if you only use it a couple months of the year (or even a couple days of the year) still costs money.

If you don't want to be connected to it at all - then I mostly feel you shouldn't be mandated to be.

If demand upon infrastructure decreases, then the infrastructure itself can also decrease.

We don't need to solve that problem in advance.

Hope this ends up being true, and that solving it in advance is not required because that would mean the utilities would not have pushed back. I just feel like they will unfortunately. But baby steps with the balcony seems like we're heading in the right direction. Just wish we'd move faster.

But then you have that week or 3 when you need all the infrastructure.`

Sure. Shit happens.

The system we have now is imperfect. The system we will have in 10 or 20 or 100 years surely will be imperfect, as well.

We must not let perfect be the enemy of good: If we do, then we'll never get anything done at all.

In power grids the system must be able to handle peak loads for weeks at a time. Either it will shed loads (aka shut off electricity) or things will explode. A black start cannot be allowed to happen as it would be catastrophic

Peaks don't last for weeks, but yes: Load must sometimes be shed.

That happens today. It will happen tomorrow. It's imperfect. This imperfect nature doesn't mean that progress must cease, or that all things must be forever maximalized in search of perfection.

> If enough people were knocking several cents per kWh off their bills, would they just end up charging more for the infrastructure to make up for the loss?

Traditional residential electric utility billing puts a lot of emphasis on usage, but when there's a lot more residential solar, that ends up not reflecting the costs very well. I think, over time, you'll see things where you pay a distribution fee per kWh in either direction, and then also pay for energy input and get paid for energy output. You might also see a demand charge that scales with your connection size or your maximum load/generation. If you don't have local generation with export, everything kind of mushes into the usage charge, especially if it's tiered... but when you exporting with net metering, you pay the same bill for exporting 950kWh and importing 1000kWh as someone who imports 100kWh and exports 50kWh, but one customer is using the grid a lot more than the other.

You see something like that with California's NEM 3.0 tarrif setting export price to the 'avoided cost' instead of offsetting import one for one. Under NEM 3.0, the utility is disincentivizing using production credits as long term storage. They prefer you use or store your energy onsite; if you can export while costs are high, that's nice too.

>how far are we from a more plug and play home solar system that becomes a primary energy source as opposed to a limited secondary source?

We don't need a more plug and play system. A zero agreement interconnection for whatever UL certified 300W-ish scale is fine and should be widely deployed.

There needing to be interconnection agreements with your utility and an inspection is not a blocker that needs to be removed. Most places require a licensed electrician for complex work, having the electrician fill out a form and having a utility inspection is how things should be.

Apologies if my reply here is not understanding you, but this is counter to my experience. Plenty of people still want to handle their own energy production even if they have grid access. I've built off-grid houses. Most of the utility production is already renewable. Many people still choose to live off grid even though that's the case. It would be epic if there was a plug and play, house-scale option because the cost of installation today is... epic (so epic in fact that the overall cost of install has actually gone up even though material costs have come down). Admittedly off-grid installs are a tiny fraction of places on the planet, but it's the trigger that led me to ask about this.

Perhaps you're just responding because I brought up grid tie (fair!), but I'm wondering why not aspire to remove the blocker, which would mean de-risking the installation so that laypeople could do it without having to get an electrician involved (which is what's so amazing about balcony).

If you want grid tie-in, a certified professional needs to be in the loop to verify all of the rules are being followed because incorrect setups are dangerous to other people. Also insurance probably doesn't want to insure your home if someone with questionable knowledge is setting up wiring and energy production.

Outside of cities, outside of grid tie, setting up your own micro-grid often can be done without any external intervention. You have to know things to do it though, I don't think it is a desirable state of things for just blind plug and play.

What you say is true, but do you not think there's a way to make it so that the risk is taken out of it so you can expand the number of people who are capable of doing the install? I mean, I personally think there is, but I respect you don't feel the same. I just end up with a $10,000 bill, for the labor, to do what seems to me like a very straightforward problem to solve.

It's not straightforward. If you do it wrong you kill people. Your house burns down, you burn your neighborhood down, you electrocute utility workers doing maintenance, you contribute to grid instability which is already a tight balancing act.

Can you make plug and play possible? Sure but you're just shifting the verification to a different layer and then you have to make it illegal to posses or sell any thing but the safe engineered products and you have to spend a bunch on enforcement to make sure only the safe stuff gets put in practice (not to mention replacing all the existing hardware and making it illegal to maintain)...

Modern consumer products and safety rules insulate people so much from the dangerous parts of existence that people get bothered when everything isn't like that and then want to go pet the big stripey orange and black kitty... not realizing that guardrails and safety nets aren't everywhere in existence.

And putting up those guardrails is EXPENSIVE. You want those instead of professional installation costs? Sure but the solar system you bought just got 10x as expensive as a result saving you nothing.

A house costs what... $250-500k to build these days? $10k for a major update to the build is nothing. Requiring expertise to verify dangerous things are done correctly is appropriate.

I'm 100% certain you can do it yourself.

We get Chinese solar panels here. $175 and produces 550 watt.

We then get Chinese MPTT inverters, always 2 if you run your fridge on it lol. $350 ish for one. The 5kW model. It's all one and the same.

You need a minimum of 3 panels.

So for less than $1000 you have 1.5 kWh with no storage.

Connecting the panels requires some care to ensure you stay within the parameters all GPTs know. Two pictures is all it takes. The spec label of your panel and that of your inverter.

I can't stress enough how easy it is.

The output of your inverter is 1 phase power. You can route that anywhere in your house safely since houses have.. circuits. So once the circuited is moved to the inverters grid, its seperated.. at the circuit breaker.

The scariest part was driving a screw through my roof.

Regulation aside, a significant issue is physical area. Most people won’t have access to enough area in the right direction to make it a primary source.

There’s a legit grid stability issue for solar in general, balcony or no.

Usage varies second by second, so the grid relies on physical inertia in the form of rotating turbines. Panels have no inertia; therefore, the more you have the less stable the grid gets.

That is however something which can be fixed by grid-scale batteries. Or home systems, for that matter, if they have batteries and some equivalent of Victron’s PowerAssist.

(Which limits the rate at which power draw can change. Very useful when you use a house-sized generator; it amounts to synthetic inertia. I have a 7kW generator, but a 7kW step load would stall it.)

Plus /actual/ flywheels to compensate for non-synchronous generation: https://www.esbinternational.ie/case-studies/details/moneypo...

You would need supercapacitors, but you can make an inverter emulate inertia almost as well as flywheels, and more than well enough to not make a difference once you push the energy into a few kilometers of non-zero impedance grid.

supercapacitors are quite difficult because they can explode

I have some news about flywheels...

Ah, this is why I come here. I had no idea that was the case. I feel like there was a story going around recently about how hard it is to restart some power generator if it gets knocked offline. Maybe it was about Hoover Dam now that I think about it (i.e., how bad it would be if the Colorado gets too low).

Utah passed a balcony solar bill; I think they're the only ones so far. Oregon tried in the short session last year, but it got shut down by fire marshall type people, sadly.

Interesting on Utah. Re Oregon, was the fire Marshall acting in good faith in that scenario? Recently reading about fire-truck size in the US I start wondering what the motivation is for some views about things around fire safety (amongst a million other things). Maybe good faith is too cynical. Maybe just hard-to-change attitudes.

Hah - I was going to mention all the other types of things the fire people seem to be blocking, but decided to stay focused. But yeah, it seemed like 'aversion to change'. "Firefighters might trip over solar panels on balconies" or something kind of far-fetched sounding.

This is funny. You might notice that I write insanely-long comments because these types of things pop into my head every time on HN (better get ahead of it because people will pick apart my quick comment if I don't cover as many bases as possible in the original comment!). Your method is better! I have to learn how to be more "focused" and let folks just do their thing and then reply succinctly like you did here.

Good plan.

Firefighters are infamous for creating elevator regulations that require being able to rotate a stretcher, which lead to less elevators duet to the immense costs, which is both completely unnecessary and defeats the entire purpose of the regulations for safety since now they have to drag injured people down stairs

They are also dragging their feet on 'single stair' reform, despite single stair being perfectly safe with adequate construction techniques

https://www.pew.org/en/research-and-analysis/reports/2025/02...

Its especially egregious because 2 stair builds are easily and often designed with more distance between stairs and rooms than single stair builds are.

I saw that Virginia and Maine have a little bit of momentum towards balcony solar. This is the video I saw that in: https://youtu.be/2RqhK2w8rrA

A standard rooftop solar install with micro inverters is already pretty much plug and play. Wiring it up is the easy part.

Even a more complex system with large centralized inverters and battery backup can be about as plug and play as a desktop computer if you use an all-in-one inverter/charger/controller.

The challenge is scale. You can't take 10kW of solar and plug it into an outlet. It requires more hardware and wiring than that.

but you CAN just plug all of your stuff into the inverter.

It’s primarily a regulatory issue, and more states in the US will approve it over the coming years.

I don't see anyone replying to you here, and I don't know what your background is in this, but I think and hope you're spot on here. The more I've read replies in this thread the more I think this is mostly regulatory and maybe slightly a hardware issue (hardware issue is that there needs to be some kind of plug on an electrical panel that would remove the risks of having to pull the face off the panel, install a new breaker and connect the inverter).

I've worked in clean energy for about a decade, building analytics software for DER providers (solar, batteries) and EV companies, and I build large-scale portable battery and solar systems as a hobby. I keep up with the industry and the regulatory environment closely via podcasts, newsletters, and conferences.

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