Has anyone ever applied to the DNO to install extra solar?

NibblyPig

Apparently you're limited to about 5.7kw of panels (3.6kw? inverter) unless you send an application, which takes months, and I was told they just say 'yes' or 'no'.
I was wondering if anyone had any experiences with this, so I might be able to figure out if it's feasible or not. 

Martyn1981

Hiya. Quite a few folk on here have, including myself. Your installer will be able to apply and ask, to see what's possible. Most likely it will be a straight yes or no.
If you do have to go with 3.68kW limit, then see if the installer is able to cap it at export rather than generation, that way you'll be able to generate more when the house is consuming.

frozen_wastes

NibblyPig said:

Apparently you're limited to about 5.7kw of panels (3.6kw? inverter) unless you send an application, which takes months, and I was told they just say 'yes' or 'no'.
I was wondering if anyone had any experiences with this, so I might be able to figure out if it's feasible or not. 

I received a quote in late August for an 8kW inverter.  DNO application went out, response came back end of September.

It was a £7k quote to upgrade the transformer tappings.  My electrician negotiated, and end result was a yes, subject to a 5kW export limit (not generation limit), for no charge.
The formal approval was granted by 20th October
In summary, it’s not a yes/no.  It’s “Yes, but we have to do xyz, and it will cost you £abc”.  But still, you might have your connection granted without any charge at all.

I reckon that the sooner you apply, the more likely that permission will be granted without charge.  Once solar is in the middle of the S curve, the DNO will tighten up their connections policy for new applicants.

NibblyPig

Thanks very helpful.
I spoke to 4 solar companies to get quotes, and each one argued tooth and nail with me about my solar needs. I explained that I want to be eco and I want to generate as much power as possible, it's not about the standard boring cost savings (although I've just moved into my house and expect to be here for decades) but the fact that it's a hobby to automate my house and I'll be implementing all kinds of interesting methods to distribute and export solar as well as have an EV and eventually battery tech when it comes down if I don't DIY my own batteries before then.

I asked about the DNO and they were reluctant to admit you could apply for more than the 3.6kw or whatever it is, and said you can't ask for what you want you just have to apply and they straight up say yes or no. I don't think it's quite that strict and flat as you say there's room for negotiation...

In the end I found someone that agreed to do half my roof and then in the future I can apply to the DNO and do the other half. It was a good quote compared to others, so I think I'll do it.

I have east/west facing roof and they quoted to install 12 x 380 JA Solar panels on it. They said it'd be a squeeze but should be doable. That gives 4560kw presumably for a 3.6?3.8? inverter or whatever the DNO requires. Does that sound reasonable or should I be pushing for an application? I want them on both sides for more even distribution...

Hexane

I would say push hard for an application otherwise you are never going to get what you actually want. It can sometimes take weeks (and not many weeks) rather than months.

9.1kW of panels with a 7kW or 8kW dual MPPT inverter would be nice...maybe with export (but not generation) limited to 5kW or 6kW, if that were absolutely necessary.

NibblyPig

I think it's a reasonable compromise to do half and then see how it goes and apply for DNO and do the other half, doing a DNO application sooner rather than later also makes sense.

Do you think there's any reason why it's a bad idea to do half then half?  I thought perhaps installation costs but I think they'd be roughly double anyway doing it all at once because it's a 3 storey townhouse and you'd probably have to erect new scaffolding the opposite side to do it anyway rather than get any real cost saving...

Martyn1981

I think you'll find that doing it in two parts will be more costly. I see your point about the scaffolding, but you have to remember the team will allow for 4 journey times (there and back to install, and again to remove), so you are doubling that. Also the inverter will get complicated, as you won't want to oversize it on one install, in case the second is refused, but it will then be too small for the second if you double up later.
If you install ~4.5kWp, then you will probably want something along the lines of a 3.6kW to 4kW inverter, which might have dual MPPT's, allowing it to treat different orientations separately, but also may not. Whereas for the E/W install, you don't need to double up, as both rooves will never be maxing at the same time, so something around 6-7kW may be the most efficient inverter choice ....... but oversized and inefficient for one roof.
Also consider that for the 'AC team' doing the internal work, doing the job twice will double the work, but a larger single job won't require any extra work, just larger cables.

Solarchaser

Definitely all at once, straight answer from dno, single install, clear cost and all done and dusted imo

NibblyPig

I got JA Solar 380 x 24-panel, 9.12kW system on a Solis dual MPPT 8kW inverter estimated cost £8,800 from one company (they need to send someone to give a definite quote I think), is that reasonable?

Another guy quoted me £4778 for 12 x JA Solar 380 Solis Inverter (so one side of the roof only).

I also don't know if JA Solar 380w is the best. I was told getting 12 panels on would be a squeeze but doable. Perhaps I can spend more for more efficient (not bigger) panels, or perhaps it's not worth it. Any thoughts?

Solarchaser

Generally speaking £1 / watt is a decent quote, and since you are high roofed, then I'd say it's a decent quote, and a decent size of system.

High efficiency panels, its a cost vs reward scenario,  id say at 8kw, you should be good personally 

Hexane

NibblyPig said:

I got JA Solar 380 x 24-panel, 9.12kW system on a Solis dual MPPT 8kW inverter estimated cost £8,800 from one company (they need to send someone to give a definite quote I think), is that reasonable?

Yes that's a good price. The inverter is probably the higher end version of the 6kW one that I have (I think they also do a 7kW one and various others).

NibblyPig said:

I also don't know if JA Solar 380w is the best. I was told getting 12 panels on would be a squeeze but doable. Perhaps I can spend more for more efficient (not bigger) panels, or perhaps it's not worth it. Any thoughts?

380W is probably the sweet spot for price/efficiency right now, so going higher is unlikely to be worthwhile since you're not especially short of roof space. Be cautious of fitting panels too close to the roof edges or roof ridge (issues with wind damage) - go for a couple less panels if necessary.

Don't forget to investigate anti-pigeon mesh.