- cross-posted to:
- climate@slrpnk.net
- cross-posted to:
- climate@slrpnk.net
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).
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Wait, how do these things work with the electrical grid in my house? I mean I understand how I can use the wires in my house to consume electricity, but how does it work when plugging in something that generates electricity?
Whether current is flowing into an appliance or into the grid depends on which of the two has the highest voltage at any given time. Current is the result of a voltage difference in a closed loop.
These batteries have a built-in inverter. The inverter can produce an output voltage. The electricity grid uses AC which means the voltage is not constant but rather always changing in a sine pattern. To control the current, the inverter can follow the sine pattern and increase amplitude to control an outgoing current, or decrease it to control an incoming current.
By the way, in many cases you don’t want to power the grid. So these batteries usually work together with a sensor placed at your electricity meter. That way they can induce just the right amount of current to power your home appliances without sending something back to the grid.
the same way it works when they connect a new generator to the grid, or solar panels on your roof
there’s nothing directional about a power point: it’s just copper wire
Unfortunately there is directionality when it comes to the protection. I’d love to see a fault study of a house with a bunch of these on different circuits.
The circuits should have breakers.
Yea but surely electricity does not just flow from my house to the grid, just like that? Also what if I plug in something like a solar panel, but I have no consumption on my own electricity? Surely it doesn’t just flow into the grid, i.e. out of my house? Or does it?
That’s what net metering is.
i know sometimes it does… it can even make your meter turn in reverse!
it’s pretty common for rooftop solar to supply the grid if you’re not using all their capacity
Okay haha, I did not know that. I wonder if that works where I am (Denmark). Not sure if we have regulation when it comes to this stuff.
I have one since December that i had put together by myself because of the railing dimwnsions. 630W, very good orientarion, on a sunny day produces around 2,5-3kWh. And that is in the winter. It should pay itself in max 3 years. I can only recommend it.
A sunny day in UK, isn’t that once every three years?
probably, but i dont live in the UK, should have written it
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.
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.
The UK though has the added spice of the uniquely unsafe ringmain wiring standard, in which 24A cable in the wall is protected by a 32A breaker at the distribution panel. It’s only “safe” if the load is evenly balanced around the ring, and the ring isn’t broken (that’s why UK plugs need fuses in them - to make it harder to severely unbalance the ring by pulling 32A out of a single socket, and equally to try and protect the appliance cable if a short or similar tries to.)
I’ve not sat down with a pen and paper to work out how having a generator somewhere on the ring affects things - presumably the authorities have…
It’s probably okay, in the usual UK buildings, for the first 24h you’d be cooking the dampness out of the wall.
800W is just 3.5A so probably can be managed
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.
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.
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”.
more than a few smashing down from a balcony.
Then again, it is cultural tradition to let things fall of a balcony in Germany.
They are cool, although there are risk connected to using them. In some cases an appliance can draw more power than the circuit is rated for without tripping a circuit breaker.
They are not legal in Norway, and with all houses being made out of wood it makes sense, but I guess the risk in UK or Germany is lower.
Technically they’re “not illegal” in Norway if installed on a separate breaker. It’s not as easy as in Germany, but it’s possible.
They also can pose a risk for linemen and electricians. A circuit can remain powered even if the breaker or load break switch is disconnected. That is, unless they have a feature which disables power output automatically when grid power is lost?
All of these “balkonkraftwerke”, as they are called in germany, are grid bound, meaning they instantly disconnect and stop working without the grid. There is zero danger to them.
A circuit can remain powered even if the breaker or load break switch is disconnected.
They are specifically designed so that this does not happen.
BTW part of the UKs standards for household wiring comes from a time where the idea was to heat with electricity from nuclear power. Which is one reason why each appliance also has an extra fuse in their respective wall plug - not a bad design.
That is not why UK plugs have a fuse in them. UK plugs have a fuse in them because the wiring standards date from a time when the UK was trying to save money and copper because of the war, so they allow for the fuse in the breaker panel to be higher rated than the actual wiring in the wall.
The fuse in the plug is to prevent a broken device, or overloaded power strip, drawing the full current the breaker will allow, causing the in-wall wiring and/or appliance cables to burn.
It’s a terrible design. [ETA: Ringmains/UK domestic electrical distribution are a terrible design, I mean. The BS1363 plug/socket is a nice design driven by compensating for that.]
The UK plug is one of the best around. It’s only downside is that it’s chunky. By putting the fuse in the plug, the protection can be customised to what is attached.
It also is designed to be almost impossible to fall out of a wall socket. As well as mandating the pin connection order and safety shielding. The sockets are also gated, stopping children sticking stuff into them.
Even internally they are well designed. The live wire is the weakest link. If pulled, that will tend to fail first. It will, however be held internally by the neutral and earth wires. The earth will be the last to fail.
The side entry also means that the plug locks into place when the cable is pulled. If the plug or socket fails catastrophically, the earth pin will be the last to pull loose.
It’s only downside is that it’s chunky.
Nuh-uh - it can land pointy-side up, that’s a big downside for someone as clumsy as I am.
I would call that a feature! It means we can use them as caltrops if the French ever invade!
/s
Based on my electrical engineering course the UK has one of the weirdest wiring standards in the world, having some of the shittiest baseline wiring and subsiquently trying to make up for it with some of the most stringent regulations around protection devices such as RCDs and additional fuses.
They are also weirdly patriotic about their plugs. Suggesting that BS1363 was driven by necessity of poor wiring standards rather than being a gift from God to her chosen people is tantamount to standing in the street and pissing on the Union Jack.
(Source: Am British. Well, was. BS1363 plugs are very nice. But honestly, Schuko is fine as well. They’re just plugs.)
Wouldn’t it be easier to have several fuses at the breaker panel?
Easier, but more expensive. The driver for the ringmain system was to save money (& copper) by using less & cheaper cable in the walls than an equivalent radial layout (as used everywhere else in the world.) It has half as many fuses and uses less wire than radials, with the only downsides being risk of fire and some horrible undetectable failure modes - what’s not to love?
(e.g. Undetectable failure: if there is a break in the cable in the wall (bad DIY, say,) everything still works - because although you broke the ring, the other end of each half is still connected, and all your appliances still work. So now you have two 24A radials in your walls, connected to a 32A breaker, and nothing stopping one of those cables being overloaded (if the break is nearer one end than the middle, it’s practically guaranteed that the longer half is overloaded.) Horrible design.)
Oh… That’s… Not good😅
