Solar feed-in G99 Refused

[JohnnyUK]

Hi All

We're part way through a solar installation with Octopus, with a pause for the G99 (larger inverter) Application form being submitted by them.

It has come back from the network (I cannot recall who it is) as "Refused Permission", which means we can keep the 5kW inverter, but only with a limited feed-in of 3.68kW.

Anyone know why they would refuse this?

Thanks

john

[119]

Isn’t it something to do with overloading the network or local substation or something?

[JohnnyUK]

119 said:

Isn’t it something to do with overloading the network or local substation or something?

A capacity issue somewhere I guess, but even Octopus were surprised.

[mrmistoffelees]

Capacity or local balancing. There's a few new large installations gone up within the last few months recently around me and at peak times I'm seeing Voltages around 251/252 but on sunny days like today it was nudging 259/260 for a time. Dull days and it's right back off again. I'd imagine something similar, maybe see if you can get some data on that kind of thing?

[AyBee]

I assume they don't have to give a reason?

[biggiles]

mrmistoffelees said:

Capacity or local balancing. There's a few new large installations gone up within the last few months recently around me and at peak times I'm seeing Voltages around 251/252 but on sunny days like today it was nudging 259/260 for a time. Dull days and it's right back off again. I'd imagine something similar, maybe see if you can get some data on that kind of thing?

An easy way to check rough mains voltages is with smart plugs - many of them read out the mains voltage. If you're high (I forget the regs but the magical Mr Mistoffelees has some numbers above) that could easily be the reason.

[4Q]

It's only the export which will need limiting, not the actual production. Most inverters are able to do this easily by monitoring current flow with a CT clamp in the incoming supply. If you got a 5kW system with a battery it's unlikely that you will have more than 3.6kW excess generation most of the time anyway.

[silentbrown]

As mentioned, it's to do with capacity of local infrastructure.

I'm not sure of the physics of it, but exporting power to the grid raises the local grid voltage slightly. And the more local installations you have, the higher it goes.

You can get your DNO to install a logger and they should drop the voltage on the nearest pole if it's going over 253V (although ours tried claiming at first that an 'average' under 253V is acceptable. It's not!)

How big is the array, and do you have a battery planned? If it's a DC battery, your inverted can charge that and simultaneously export 3.68KW, which (with careful planning) allows you to minimize the loss due to the export restriction.

[steveamv8]

JohnnyUK said:

Hi All

We're part way through a solar installation with Octopus, with a pause for the G99 (larger inverter) Application form being submitted by them.

It has come back from the network (I cannot recall who it is) as "Refused Permission", which means we can keep the 5kW inverter, but only with a limited feed-in of 3.68kW.

Anyone know why they would refuse this?

Thanks

john

You haven't said if you are putting battery storage in.

Remember none of the companies are suppliers they are all brokers, so they dont actually supply you.
If you go with the mind set that you are putting solar in with batteries to save you an electricity bill and then whats left sell it back to your broker
It makes you think in a whole new angle.
They will try n rip you off by giving you a crap tariff for selling it to them but not when it comes back the other way.

The second way , watch ther arse twitch when you say you want a gateway to power the house if the grid goes down
You get the call centre chimp get his book of excuses out to make it as hard as possible or just downright lie
with bullst .
been there done that