DNC discrepancy reported by our DNO - any ideas how to correct?

[user 37666]

I have been trying to set up the excess solar generation output with Octopus, to get a little bit of money back from the stuff we don't manage to use, and Octopus have thrown it back at us with

"...have received a rejection from your DNO as they have been notified of a Declared Net Capacity (DNC) different to the one on the MCS certificate"

I believe Western Power are in charge of distribution in our area.

The original suppliers (Cisco Homes) have, in just the last month or so, gone into liquidation, so we can't go through them to have the certificate corrected. The MCS site states that we can apply directly to have it corrected but the problem is that I have no idea what is supposed to be corrected.

The installation consists of 17 x 405W panels feeding a Solis S5-EH1P5K-L hybrid inverter, with 4 x 5kW FOX ESS LV5200 batteries.

Having inspected the MCS certificate, the total installed capacity is listed as 6.88kW, whilst the Declared Net Capacity is listed as 5.50 kW

As I understand it, the inverter is capable of momentary peaks of 5.5kW output so I assume this is why this figure has been declared as the DNC, so is it as simple a case as requesting the DNC be set to the same as the TIC, 6.88kW?

Thanks in advance,
Jonathan

 

[user 37666]

Further to this, I've had a response from Western Power to state that our connection was registered as having a maximum export limit of 3.68kW, so I do at least now know why there is a discrepancy.

I have written confirmation from Western Power, however, that a 5kW export is absolutely fine on the grid where I live, and that "all I need to do" is find a supplier to fill in a new form to show 5kW export capability.

Is this something I can approach any solar installer about? I am slightly confused as my understanding, from National Grid's own guidelines, is that a G99 for >16A connections, must be completed PRIOR to installation.

 

[gustaff]

Fill in a g99 application ( I have just submitted one and it has been accepted, so it isn't that difficult, just read the questions until you understand what they want.) Send it in on line explaining the situation. Or if you are happy with a reduced export amount and you are able to control export to the grid. Send in a G98 notification.Your batteries will be taking most of your solar anyway.
Just seen you have a Solis inverter these are on the approved list and export can be limited.

 

[user 37666]

Cheers for that, I'll take another look. I was put off by some of the wording suggesting I needed to be 'competent' and, well, I've been called many things in life but competent with electrics isn't one of them!

Even with the 20kW of battery storage, we exported 1100kwh between late April and late August this year, so it would be nice to try and avoid losing 25% of that by sticking to the current DNO application the solar installers mistakenly set up.

Thanks again

 

[gustaff]

The link attached is for my DNO, they have lots of helpful info on their website.
https://www.enwl.co.uk/get-connected/apply-for-a-new-connection/generation-and-storage/

 

[johnb2713]

Cheers for that, I'll take another look. I was put off by some of the wording suggesting I needed to be 'competent' and, well, I've been called many things in life but competent with electrics isn't one of them!

Even with the 20kW of battery storage, we exported 1100kwh between late April and late August this year, so it would be nice to try and avoid losing 25% of that by sticking to the current DNO application the solar installers mistakenly set up.

Thanks again

Have look on the threads on here, Octopus no longer need your MCS certificate.

 

[user 37666]

Have look on the threads on here, Octopus no longer need your MCS certificate.

I was vaguely aware that they don't, but the DNO has highlighted the discrepancy between the two and won't allow us to move forward until it has been resolved.

As it happens, a suggestion elsewhere has moved things on a step. Our installer was registered with HIES, so I approached them yesterday and they are going to arrange for an outfit called Flexi-Orb to make all the necessary corrections.

Thanks for the link gustaff. I have tried to understand the G99 forms but as a non-electrician (and a general all-round numpty outside of my sphere of knowledge), it mostly makes my head spin. If the Flexi-Orb folk can resolve this for us, and hopefully at no cost through the HIES scheme, then it's happy days.

Thanks again for the replies, they have been appreciated

 

[johnb2713]

I was vaguely aware that they don't, but the DNO has highlighted the discrepancy between the two and won't allow us to move forward until it has been resolved.

I didnt know the DNO was involved in who supplies your power, I really dont see why they need to be to be honest.