I mean, it makes sense to me that consumers can’t be pumping energy into the grid with no way to cut it off, but I’m not a lineman or some sort of civil engineer or whatever.
But if I were a lawmaker, I’d be on the phone with the Germans, who have 1.2M of these connected, and figuring out if and how they’re doing it safely. But lawmakers seem to be somehow incapable of reaching out to people who know fuck all about anything.
The microinverters stop feeding in if grid goes down. So it’s safe.
Hmmm, I wonder how this would affect things in the future where this is widely used.
I.E. if you had both widespread solar usage and some kind of large blackout, would it be hard to get all your solar back online because it’s all in the “waiting for the grid” state? And the grid can’t come back at capacity because all the solar it’s expecting is out?
I assume people smarter than me have this figured out, but just a random thought if anyone knows more.
You turn on parts of the grid at a time.
What happens when someone makes an unsafe backfeed into a downed grid and then other nearby inverters detect the current and bring themselves back online? Is there a way to detect if the load is being delivered from the utility vs from incorrectly configured solar or generator installations?
Some others are arguing back and forth about this elsewhere in the thread and I see the reasoning: unpermitted systems could accidentally energize isolated portions of the grid during downtime, which might trick properly installed systems to also come back online, and you have a runaway effect where there is enough current present to allow addition safety systems to be fooled.
There isn’t any data transmission over the wires; there either is current, or there isn’t. Arguing over permitting is moot - either safety systems can handle this scenario already, or they can’t.
All paperwork does is slow the relief of dependence on the utility, which hurts their profits.
The same thing that currently happens when somebody does that with a gas generator? Linepersons get zapped… people get sued… etc…
There isn’t any data transmission over the wires…
That’s very wrong. Not only can you extend Ethernet in your own home using your power outlets, the power companies have been reading meters this way for decades.
Linepersons get zapped… people get sued… etc…
Kinda seems like something you might want to avoid…
Obviously. I was just pointing out that it isn’t an issue unique to solar.
It is unique to “balcony solar”. Typical solar systems require permits and inspections before connecting.
No it isn’t. The same thing happens with the kind of gas generators you can get from your local hardware store all the time.
How do you know? In a typical solar system, you have to have a permit, which requires an inspector to come out and ensure everything is configured correctly and safely. These don’t require any permits, which is great for making them more affordable and accessible, but there’s also no one coming around to make sure that anyone is doing it safely.
I know it because it’s in the spec necessary for licensing. It shuts off in under 20 ms so you can’t even get shocked by the prongs of the plug if pulled out.
What license? Who is coming to verify your license?
It is a commercial product, connected to the grid via a standard schuko plug, sold in Germany. It has to be compliant with the local law to be sold legally.
It all shouldn’t be so difficult to understand.
It has to be compliant with the local law to be sold legally.
So you can’t buy raw solar panels or inverters in Germany?
It all shouldn’t be so difficult to understand.
It’s not, which is why I’m not sure why you’re struggling.
So you can’t buy raw solar panels or inverters in Germany?
Sure you can. Solar panels will be fried by grid voltage more or less immediately if you connect them directly to a wall socket and become useless.
You cannot buy a PV inverter in Germany (entire EU really) that doesn’t automatically shut off if it doesn’t detect a frequency to sync against from it’s AC side, unless it can run off-grid in which case it has to disble the grid connection within the same 20ms.
Inverters in the US are all listed to UL1741-SB which dictates that they shall cease to energize their AC outputs if they sense an absence of grid voltage.
Now, one thing people are ignoring is that UL1741-SB allows for islanding protection, and the disablement of it. If an inverter has its settings changed such that islanding protection is OFF, then the inverter will keep sending power to the “grid” because it thinks it’s operating on a microgrid that was previously disconnected from the larger grid via a Microgrid Interconnection Device (MID).
The settings these inverters have are user-settable, which means they need to be checked by a qualified person, either a contractor, engineer, or inspector. These settings must also often be checked by the utility you’re interconnecting to before they allow you to energize, so usually all of these parties have eyes on the inverters’ settings and can stop work before energization until things are corrected.
Ultimately I agree with you. If we don’t want to have to need inspections for every solar installation, especially residential ones and especially where plug-and-play solar modules are used, then inverters need to have their settings pre-configured for the grid code in the factory that then cannot be changed by the user or operator in the field. That would be a way to shoe-in this kind of installation.
Hard setting grid codes into inverters prior to shipping to site might be overly conservative though, especially as utilities change their grid codes over time. You need to have a way to update those settings, which could be using a wireless portal hosted by the inverter OEM with credentials made only available to the OEM. Problem with this is that then you shift the burden of configuration to the manufacturer which already has a ton of other UL standards as well as rules and regulations to follow.
What do y’all think?
I agree with everything you said except shoe-in, because it’s shoo-in.
But you articulated (better than I was going to) the number one issue. Power companies need insurance and their insurance will be affected if ordinance permits basically unchecked generators being plugged into the grid. And before anyone says it, you are not allowed to just plug your generator into your house. Does it happen? Yeah, people have been dumb since day one.
But there are transfer switches that allow for this operation in a safe manner, and the easiest way to deal with this is to have them installed by default in new construction, and to provide incentive for upgrading your panel to include one.
Inverters in the US are all listed to UL1741-SB which dictates that they shall cease to energize their AC outputs if they sense an absence of grid voltage.
No, they are absolutely not. I don’t know where people are getting this idea. Many inverters aren’t even UL listed. There is absolutely no requirement for them to be. If that were the case, off-grid inverters wouldn’t even be allowed to exist. I own several that do not have this capability and are not UL listed.
they need to be checked by a qualified person
Not in the case of Utah’s new “balcony solar” laws. That’s the problem.
which could be using a wireless portal hosted by the inverter OEM with credentials made only available to the OEM
Oh goodie, I’ve always wanted DRM for my inverter.
What do y’all think?
I think it should just require a permit, like every other solar installation. Unless we can provide data to show that it’s not a problem in existing areas where this is common, and we research and follow their regulations.
Many inverters aren’t even UL listed.
Yes but many inspectors and insurance companies won’t want you to install electrical equipment on “real property” or buildings if it isn’t UL as that falls into the scope of AHJs and insurance providers. If there’s something that has the potential to start a fire, you need to have safety certifications so operating the system not only reduces the risk of fire, but also selling the house in the future to a new owner doesn’t come with excess burden on behalf of the next insurer.
If your solar system is off-grid AND off-building, I see no reason that you need to have a UL listed system.
This is of course dependent on local AHJs and utilities, but UL 1741 covers both standalone (off-grid) and grid-interactive (on-grid) inverters. If you’re choosing an inverter manufacturer that makes non-UL listed off-grid inverters, I would probably be suspect of their products’ quality as it’s easier to gain UL listing regardless of how the inverter is used: off-grid or grid-interactive.
That’s the problem.
That is a problem. Off-grid inverters that aren’t certified to UL 1741-SB aren’t required to have anti-islanding protection that cuts the inverters off if there’s an absence of grid voltage. If a “balcony solar” inverter were to NOT cease to energize upon loss of grid and stay islanded, then voltage is introduced to the building’s/community’s shared local distribution system. If work were to be done on that portion of the distribution system or grid where lineman and wireman expect conductors to be de-energized, then you might have injuries as a result. Now, you may be able to say that lineman and wireman should always test for presence of voltage prior to doing work, and as a solar engineer I would absolutely expect folks to do this, but that’s not always the case. People cut corners. And in the event that certain crews cut corners, don’t check for voltage and investigate where the voltage source is, and start touching wires and introducing paths to ground, people can get seriously injured or die.
You may think that because solar panels are current-limited that this fact protects workers in the event of becoming exposed to live voltage, but any combination of voltage and current can kill.
I’ve always wanted DRM for my inverter.
In the context of safety, this is a good thing. Skirting DRM on movies or TVs won’t mean you injure yourself or others or worse. Skirting inverter settings can cause inverters to operate in ways that are unintended, and could hurt people. These things are not the same, and it’s concerning that you can’t see the difference.
Also, having locks on settings means that other bad actors are deterred from changing those settings maliciously, whether intentional or not.
There is not substitute for a qualified person operating and maintaining an electrical system, regardless of voltage.
I think it should just require a permit
Agreed
Yes but many inspectors and insurance companies won’t want you
…why would anyone care what those people want?
if there’s something that has the potential to start a fire, you need to have safety certifications
No you don’t.
If your solar system is off-grid AND off-building, I see no reason that you need to have a UL listed system.
You’re missing the point. Nothing is stopping anyone from installing off-grid inverters (or any inverter at all) in an on-grid system.
I would probably be suspect of their products’ quality
Have you ever looked at “top sellers” on Amazon? Most people do not care about quality, they just buy the cheapest shit possible.
These things are not the same, and it’s concerning that you can’t see the difference.
I see the difference, I just don’t care. It’s concerning that you can’t see the potential for exploitation, both from corporations and governments.
Easy check, grab a voltmeter and do it yourself.
Pull the plug, set voltmeter to AC, and read the voltage across the prongs. If you get anything over the usual float voltage you get from just holding the probes ungrounded, then you have a problem.By “you” I did not mean your personal solar system. I mean how does the utility know that other users that have systems connected are doing so safely?
The PRODUCT is designed to stop feeding OUT the plug if it doesn’t detect CURRENT from the socket. AC is alternating current so it pulses on and off so the solar system is doing the same. It’s turning on and off quickly and seeing if it gets power back and if it detects no power incoming it shuts off the power from the solar. It’s quite simple and ingenious.
I am not asking how the technology works. I am asking how the utility verifies that people are using compliant products.
“The utility” has never had a way to prevent you from doing something dangerous with your wiring or with the electricity they send you. The best we’ve managed has been to encourage appliance manufacturers to design their products with safety in mind, through the UL program (which is voluntary). This is why the writer talked to the “vice president of engineering at UL Solutions.”
It is more than just the concern around back-feeding the grid. These simple balcony setups connect to your home grid via a single outlet. Most US outlets/circuits are 15 AMP or roughly 1500 watts max capacity. These single circuits can only carry that much current total at any one time so if you have it loaded up with incoming power AND use anything else on the circuit at the same time … no bueno. To make this setup work best/safely you would ideally want a dedicated circuit for it which is basically non-existent today.
The safety issues really do need to be addressed because the folks most likely to use these systems are apartment dwellers and I don’t think anyone wants to increase fire risk in these scenarios.
If you use anything else on the circuit the power from the solar will just go directly into that device and bypass the wall wiring entirely.
There are a lot of circuits in the US that power multiple duplex outlets around a room. You could plug in a solar panel into one outlet and a load into another and they would be connected by a length of Romex in the walls.
Why don’t we just change the revenue model for power companies. I understand they need money to maintain the infrastructure and pay employees. If power generation becomes so cheap that it can’t sustain the company then don’t rely on that for revenue. I’d rather pay a flat rate for the infrastructure and operating costs than a fluctuating generation charge. And public utilities should not be for profit.
When I got solar panels on my previous home there was a $5 a month line charge. That when went up to $8 the next year, then $10, then closer to $20. The power company (Duke Energy in case anyway wants to the shitty company’s name) was determined to make it as painful as possible for people to use Solar. They were also apparently responsible for pushing to get it illegal in that area to go “off grid” and to have a cap on the amount of solar power a home could generate. At now point did these line changes stop them from raising the normal power usage rates mind you, this was just an extra “fuck you” from them.
Many places already do charge a “line charge” if you have solar power and use little or no utility company power. You pay for being hooked up to the grid even if you barely use it.
This. This is the way. It solves this problem completely, but utilities somehow refuse it. It’s almost like their argument is not in good faith …
This is how it works in my area. I pay about $12/mo in fees, the rest is handled by solar. They don’t pay me for excess solar, instead I get credit (in kWh, not dollars, thankfully) for it and any electricity I use at night or in the winter comes from that pool. Essentially, it makes the power company a big battery for me.
That’s what your public service commission is for! (In most states). They come up with how the costs of the utility gets passed to consumers. I agree that making sure that infrastructure costs get passed to people who have solar panels, especially if they are relying on that infrastructure at sun-not-being-in-sky hours.
I’m so glad companies have enough excessive funds to use that money against me.
plug a solar panel into a large battery backup, plug the major appliances into that.
Utility companies don’t need to know shit.
My thoughts exactly. Also I wouldn’t really like to risk my stuff by connecting to their infrastructure anyway. At least over here, I saw how incompetent they are.
over here
Texas? 😂
I was going to say California. We have constant outages — having grown up in blizzards and tornados I never imagined they wouldn’t be able to keep power on here. It’s bad, like I mean when there’s a little wind it’s probably not staying on.
Serbia / Hungary.
That’s what I have. Basically a small-ish parallel electrical system that runs critical loads like a mini split, refrigerator, water heater, etc. And a small UPS for modem/server.
These can output 1800W, 1100Wh, Starts at CAD$700 then you just pay more for more storage for bigger systems.
Out of curiosity, how do you have that setup (at a high level)?
I’ve got a bluetti system for emergency power (12kWh, 6kW AC output) but I need to plug things directly into it. It’d be nice to feed it directly to my house wiring but … selectively. That is, I wouldn’t want to power the HVAC but it would be nice to not have to shuffle the fridge/freezer plugs from the wall to the inverter.
Dedicated circuit(s) with a manual switch from mains to inverter, I’m guessing? But then we get into all the extras required to do that safely and avoid back feeding the grid.
Granted, they have systems/setups specifically for whole house power but I don’t want to feed the whole house, just the important circuits/appliances.
Dedicated circuit(s) with a manual switch from mains to inverter, I’m guessing?
That’s how one of the hospitals I worked at did it. Probably wasn’t a manual switch though.
Basically made a really sturdy pergola and then mounted solar panels to it. Ran that wiring to the MPPT, batteries and inverter in the garage. Put in a new small breaker box right next to the existing one, which made it real easy to just grab the wires for the critical loads and run them over to the new panel.
No need to worry about backfeeding, as I said they’re parallel electrical systems, so it’s not possible.
Do you have a fallback if solar production is low?
Didn’t read article, but can tell headline is BS already
