declared net capacity

[germ]

Hi everyone,
I know this subject has been discussed before but I'm still not sure!
The network operator permits 17,25kwp to be fed into it's system.
Therefore we have installed a 17000 Tripower.
In order to get the highest yield possible we have fitted 20kwp onto the south facing roof which has a 10 deg pitch.
This has all been discussed with the network which got no problem with it as long the inverter limits the output to stay below the 25amps per phase, which the 17000 Tripower does.
Question:
What is the DNC? In my view it should the max Kw the inverter will allow to be fed into the network, unless there is a lower kwp on the roof.
Can anybody clarify this for me.
Many thanks

 

[BruceB]

Here it is from the legislation:

“Declared Net Capacity” means the maximum capacity at which the installation can
be operated for a sustained period without causing damage
to it (assuming the source of power used by it to generate
electricity was available to it without interruption) less the
amount of electricity that is consumed by the plant;

So for a 17000TL, the answer is 17kW.

Regards
Bruce

 

[germ]

Hi Bruce,
many thanks for your reply.
That's exactly what I thought, just wasn't sure whether they meant how many modules you got on the roof.
Would this mean that you could ad more modules to a system as long as you don't up the inverter and still get the old tariff for the extra capacity?
Regards
germ

 

[BruceB]

Yes, in my opinion. Not everyone here has agreed with me in the past on that point though. So you will have to read the legislation and make up your own mind!
Regards
Bruce

 

[TedM]

It is no longer possible to extend a system and get anything other than whatever the current FiTs rate is at the time of commissioning. So if the extension was done after 12th Dec then you would only get 15.2p (or whatever it will be for a 10-50 kW system) for that fractional part of the total capacity. Assuming you actually do increase the capacity.

 

[germ]

It is no longer possible to extend a system and get anything other than whatever the current FiTs rate is at the time of commissioning. So if the extension was done after 12th Dec then you would only get 15.2p (or whatever it will be for a 10-50 kW system) for that fractional part of the total capacity. Assuming you actually do increase the capacity.

Hi Ted
thank for your reply.
What is your view on my DNC question then?
As it stands, nobody knows how much kwp is on the roof if I declare the max kw of the inverter as DNC.
One could even upgrade and replace his old 220s with 260s and get a higher kwp without changing the module type and size!
There might still be some business after the eleventh!

 

[JD6400]

Hi germ , i do not understand ?
You have to enter the system size on the mcs cert .

 

[germ]

Hi germ , i do not understand ?
You have to enter the system size on the mcs cert .

Hi,
that was exactly my original question!
Is the DNC 20 or 17 for the stated plant?
Please read the question I posted at the beginning.
Thanks

 

[JD6400]

Scrub that I realised what i had put after i hit post !
Been a long month !
i was going to edit the post but did not want to leave a blank post .

 

[Earthstore]

The size of your system is 20KWP and the Inverter is "capped" at 17KWP, it needs to reflect this in your paperwork.
You can back this up with DNO approval, if that is how they worded their paperwork.
However, on the MCS certificate it needs to be 17KWP or it may backfire on you.
Hope this helps
Earthstore Energy

 

[germ]

Hi Earthstore,
thanks for your reply.
Its all cleared with the DNO, the've given approval and are not interested whether there are 10 or 100 kwp on the roof as long I fit the tripower 17000.
In regards of the back firing I was more worried the other way around, that they may say later on that there are to many kwp on the roof.
regards
germ

Ps:
this does seem to imply that one could retro fit more kwp onto their roof, if the DNC is given by the inverter output.(in some cases at least)

 

[BruceB]

Adding a few extra panels after the event is NOT an "extension" under the legislation because the definition of an extension involves increasing the TIC, which you are not doing if the inverter is already over-panelled.

 

[SolarCity]

For what it's worth, I do agree with BruceB about the wording of the legislation and I know the DNO see it this way.

However, I'm not sure that the energy suppliers see it that way. Or at least I don't want to find out by putting 4.25kWp of panels on a roof and then have the supplier tell the customer that this system would then be in the 4-10kWp bracket.

 

[TedM]

It's worth reading the conditions in the suppliers contract. Some require that they are advised of any changes. Whether all these conditions match the requirements of the legislation is another matter but, in the first instance, the contract is just between the homeowner and the FiTs supplier and any breach of that contract's terms could lead to suspension of FiTs payments.

 

[Nutmeg2]

The Eon fits form requires the array size as well as the net capacity - I have 240 x 10 panels but a 2000 inverter so values filled in were 2.4 kW and 2.0 kWp