Are solar panels pointless?

Mikeyboy01443

70sbudgie said:

There are some battery systems (Tesla, I believe) that can operate in island mode, but as it can be a safety issue for DNOs, I understand thay you have to get permission first. 

if they shut the grid down, and i flip my isolator between the meter and the house as well, there is no way its going anywhere near the grid anyway?

what i do my side of the meter / isolator is my business, so good luck to them if they ever come knocking and tell me to shut it off...

70sbudgie

Mikeyboy01443 said:

70sbudgie said:

There are some battery systems (Tesla, I believe) that can operate in island mode, but as it can be a safety issue for DNOs, I understand thay you have to get permission first. 

if they shut the grid down, and i flip my isolator between the meter and the house as well, there is no way its going anywhere near the grid anyway?

what i do my side of the meter / isolator is my business, so good luck to them if they ever come knocking and tell me to shut it off...

I'm not sure, but the issue may be when you try to reconnect to the grid following operation in island mode. In that case, I think they could refuse to reinstate your cut out unless certain technical conditions are met.

The main reason is for safety of their fault engineers - they need to be able to guarantee there are no generators feeding back into the fault they're trying to repair. If they know you can operate in island mode, they'd just need to check that your isolator is switched - as you suggested, before they start work. If you're not home, they would still need to be able to do it.

Also, switching back out of island mode isn't just a case of flipping the isolator to on. Your system has to be operating at the same frequency as the grid, which is likely to be different enough to matter, due to the reason the power went off. Again, I don't believe it is complicated, just a case of making sure things are turned off and on again in the right order.

QrizB

70sbudgie said:

Also, switching back out of island mode isn't just a case of flipping the isolator to on.

With the usual break-before-make transfer switch, it really is that simple.

ABrass

It might be more accurate to say: it is simple when you've got the right kit installed and configured.

Ectophile

Mikeyboy01443 said:

70sbudgie said:

There are some battery systems (Tesla, I believe) that can operate in island mode, but as it can be a safety issue for DNOs, I understand thay you have to get permission first. 

if they shut the grid down, and i flip my isolator between the meter and the house as well, there is no way its going anywhere near the grid anyway?

what i do my side of the meter / isolator is my business, so good luck to them if they ever come knocking and tell me to shut it off...

If it's a conventional grid-tied inverter, then you won't have a say in the matter.  They are factory set so that they will not start up unless they can see a healthy mains supply, and if the mains goes off for any reason, they will shut down within about half a second.

Unless you want to open up the inverter and start tampering with the insides, you can't turn that feature off.

Some inverters with batteries fitted do support an islanded mode.  On mine, I have to operate a big switch to disconnect the house from the grid and connect it only to the inverter.  An extra wire on that switch tells it that it can then start up without the grid present.

Mikeyboy01443

as i said mine (and many others these days) have EPS for exactly this scenario. i have tested it by killing the power in the power meter box (the isolator fitted by british gas), i flip the isolator from inverter main feed and flip the changeover switch and i am running on EPS mode on just solar / battery then.