Who applies for DNO approval?

MancMan123

Morning 

If installing a 5.6kwp array who applies for DNO approval so all of it can be exported. 

One company have said they do it, another have said "Once you have solar setup you register with your energy provider to sell it back to the grid"

Thanks once again

Reed_Richards

The first company is correct and the second company is not answering the question.  However there may be complications and the risk of refusal if you want to register more than the standard 3.68 kW of export.  If that is what you want make that clear to your potential installer.

MancMan123

Thanks for the quick response 

The 2nd installer have only quotes for a 3.6 inverter. Can I assume that will be under rated. 

Heedtheadvice

Correct. You will have the potential to generate 5.6kWp I.e. under the best conditions but actual generation via the inverter will be limited to 3.6kW at all times and a lot less under poor conditions.

 

That will not require DNO approval as it it automatically given. Higher levels do require approval, not always given and cost a few hundred pounds (variable) plus cost of work to make the application.

With a limited 3.6kW there is some compensation I  that the inverter could be more efficient for longer. Also you will get more solar capture in the poorer periods thus generating more in those poorer times than a 3.6kW array of similar panels

Those general comments should be read and applied to your individual solar system such as if your panels are not just a plain south facing array, have shading and therefore potentially split arrays  or on East/ West roofs etc. More detail will help better competent members to help more to advise the pros and cons.

Further may be a benefit if you are also having batteries and a hybrid inverter where you can send more excess solar capture to them.

Reed_Richards

Heedtheadvice said:

 

3.6kW ... will not require DNO approval as it it automatically given. 

i.e you still have to register the system with the DNO but approval is automatic.

Boffinboy24

If you consider the second installer (you may not given they dodged your question….) you should check the inverter can actually be undersized that much. Cheaper brands can’t handle that 150% sizing. Is the array south ie you will reach peak regularly, or E-W in which case you wont reach peak and therefore it’s typical to undersize more? FWIW my array is SSE, so pretty good, and I have 5.6kWp on a 3.68 inverter. Initially I was quite annoyed as it clips a lot BUT I checked the installer modelling software and I lose only about 5% production over a year. This all falls a peak time when I am not likely to use (I don’t have a battery). BUT I will be gaining some extra production in low light, morning and evening, vs a bigger inverter due to efficiency. These are times I am more likely to use and therefore it is quite possible that financially I am better off with the inverter significantly undersized. Some installers will think about things in a more sophisticated fashion, others will just take a bog standard approach, and want to avoid a G99 application (ie allowing export over 3.68). I’m not sure what the case was with mine, but it’s too late for me as I only really learned all of this after purchasing. 

ispookie666

Are we conflating Generation with Export? 

MancMan123

My roof faces due south. 

MancMan123

I am still undecided whether to export everything I make onto the Agile tariff and buy it back, hopefully. Cheaper on the standard tariff ...... or have a battery. 

Boffinboy24

MancMan123 said:

I am still undecided whether to export everything I make onto the Agile tariff and buy it back, hopefully. Cheaper on the standard tariff ...... or have a battery. 

Longer term export is unlikely to remain significantly above import, not at the periods of time that solar is generating the most energy. The reason it is for now is because the price cap hasn’t been increased, come October things will be much closer. The market would be even more broken than it is if what you suggested became the norm. 

Battery is a complex and personal choice. If you try and maximise self usage, and export the rest on Agile, battery will not gain you that much more financially since export prices are so high now. The cost will be high since battery and solar prices have inflated a lot. Plus you’ll be waiting for the kit, most likely. 

If you are facing sue South you may want to undersize less, but I’d ask the second installers why they are under sizing the inverter so much. Seems likely they just want to do a G98 form and therefore keep your inverter under 3.68. Like I said, sometimes it’s just to save them filling in G99 paperwork or having to set the inverter up to limit export. A slightly undersized inverter (say 5k) with your 5.6kWp system will likely generate the most over a year but dependent on the kit a 3.68 won’t be that far behind. 

NoobSolar

Apply for G99 - instruct your installer to do it - to get the higher level of export, and use a better inverter (say 5kw). Consider an iboost also if you have a cylinder rather than a combi boiler. As has been said, you get approval for G98 anyway so why not go for G99 also?