HaraldvonBlauzahn3d ago

UK Government will allow "Plug-In Solar" Panels

https://feddit.org/post/27264515

UK Government will allow "Plug-In Solar" Panels - feddit.org

The original (very generic) title): > Government to go “further and faster” in becoming energy secure > >The Energy Secretary outlines measures to protect consumers and make Britain energy secure. They are speaking of panels in the 800W range which you can just buy , mount in front of your balcony or on top of your carport, and plug into a wall socket. These things are wildly popular in Germany. The do not generate a lot of power, but armotize in about three years and save real money. (Depending on how old the metering technology is, they can also make the power meter spin backwards, which I think is only fair considering how much households pay for kWh, compared to energy-hungry companies, which get most of the the massive cost savings from renewables but don’t pay for the necessary upgrade of the grid).

Show threadTar_Alcaran3d ago

One big problem with plug in solar (or batteries) is that they deliver more power than should be available, behind the fuses.

With an 800W panel, an appliance could draw about 3.5A more before tripping the breaker, which can cause problems.

It’s not very likely, but it’s also not the case that governments are just reluctant for no reason. These things being installed poorly is also quite a problem, Germany has had more than a few smashing down from a balcony.

Show threadHaraldvonBlauzahn3d ago

That’s why the power you are allowed to install is limited. And also why they shut down without powet in the socket. The safety issue was a big concern and it took years of deliberation in Germany to get to that point. You can be assured that if something like that is allowed in Germany, it is pretty safe. The safety bodies are watching these issues with hawk’s eyes, and these are professionals which know what they are doing and which move things into a good direction.

Honestly I am surprised why these things are not much more popular in any region where you need climatization in summer - they deliver power when it is most needed, and grids are at risk to fail.

Edit: Addition: If you are concerned, that the panels create more power than the wiring in your home can hold, you can reduce the power in the fuse to the grid. Say, you have a fuse to the grid that allows 32 Ampere, but the wiring holds only 24 Ampere. In addition, you install two balcony panels which have a total of 2000 Watt, or 2 Kilowatt.

Now, what you do: To be on the safe side without the panels, you reduce the fuse to the grid to 24 Ampere, so that the grid can never deliver more than the wiring in your home can sustain. Now, you factor in the panels: 2000 Watt at 230 Volt yield 2000 W / 230 V = 8.7 Ampere. Now, you subtract these from the 24 Ampere that your wiring can hold, and you get to 15.3 Ampere which you can put as the limit to your fuse to the grid. You can round that up to 16 Ampere (which is, by the way, the bog standard rating for household fuses in Germany).

The above number is equivelent to 3690 Watt. That should work, because nowadays the only appliance which draws a lot of power is the electric stove - nobody heats any more using pure electrical heaters since they are just too expensive.

Show threadTar_Alcaran3d ago

And also why they shut down without powet in the socket.

All solar systems do that, which is a good thing! It prevents lots of dead powerline workers. But that’s not the only reason, solar converters need to “tune” their AC frequency to that of the grid. No grid? Nothing to match. No power.

It’s also why, if you want a stand-alone system, you don’t just need a really big breaker between your house and the grid, but also a different type of converter entirely.

Show threadRivalarrival

prevents lots of dead powerline workers.

That’s a persistent myth, and it drives me nuts every time I read it. If power line workers are working on something that is supposed to be dead, they treat it as live and work it with hot sticks until they have bonded all the phases together and to ground. This is done both at the point of disconnect and where the work is actually being done.

Even if they didn’t do this, your little inverter is trying to backfeed the entire grid. The load it sees is indistinguishable from a dead short. Your inverter would overload and trip offline, even if it wasn’t watching the grid voltage and frequency.

There just isn’t a special risk to power line workers.

Mar 18 at 12:00pmWeb
Show threadTar_Alcaran3d ago

Hmmm, I’m not an electrical engineer, and really not a line worker, but I do workplace safety for a living. I was sure you’re wrong, but it is indeed not listed anywhere in the sector’s risk inventory here. I stand very corrected.

There is a generic “Make the site safe from both ends” risk mitigation though, and it makes sense that you take the same measures no matter what the source of the potential risk. Doesn’t matter if the cause is “all the solar panels” or “Some absolutely moron did things wrong several decades ago” or just plain “shit broke yo”.

Show threadRivalarrival2d ago

There is a generic “Make the site safe from both ends” risk mitigation though,

There is, indeed. One of the “sides” they have to consider is the possibility of a live line coming into contact with the disconnected line that they are currently working on. Lines crisscross frequently, and in the aftermath of a storm, a downed wire on one line could bring it into contact with and inadvertently energize another line.

The steps they take to mitigate the risk of an entire neighborhood worth of power being dumped onto the line they are working is more than adequate to mitigate the risk of backfed solar: They deliberately bond all phases together on the dead line, so any fault is shunted through the short and away from the workers.

I’m saying that the “risks” of backfed solar are far less than the risks that they already mitigate, and certainly do not justify keeping plugin solar off the grid.

(I am not saying that backfeed inverters don’t need to mitigate the risk as well; I am saying that mitigation at the device level is one of several redundant safety measures.)