Changing system capacity - FIT

Martyn1981

Dave_Fowler wrote: »

I'm considering adding a further 2.6kWp to my system by putting more panels on a separate detached, brick built, tiled roofed garage. I understand that as this is an extension, I'll need an EPC rating of D or better. I take it that it's the EPC of my house that is calculated, not the building to which the panels are attached. The garage is not insulated in any way.

I would need a separate generation meter as the garage is detached by quite a distance (but does have a 30A electricity supply connected to the house consumer unit).

Dave F

Hiya Dave, hope you're well. First things first, have you read my 'troubles' about EPC after commissioning date? If not, then simply know this, you need that EPC on or before the commissioning date, not before the FIT application date, as OFGEM have decided to use the original application date for extensions.

It's all a pointless, stupid mess, but long answer short, just make sure the EPC is not dated later than the commissioning date on the MCS certificate, or you'll get the lowest tariff rate, about 7p.

Next, check everything with your current FIT provider, but my understanding is that the EPC relates to the property that has the MPAN, not where the panels are located, since they could simply be on a ground mount attached to ..... well ..... the ground, not a building!

Can I be nosey and ask how much PV you have already, and what the sum of the inverters will be? Have you asked the DNO for permission if potential output would exceed 3.68kW?

Lastly, and this gets a bit complicated, but will the new system have better or worse generation (per kWp) than the older system. If similar or better, then you could consider sharing the TGM. I'll explain if you want, but if it's too far to cable (or re-cable) then it's not worth bothering about anyway.

Mart.

Dave_Fowler

Martyn1981 wrote: »

...
Next, check everything with your current FIT provider, but my understanding is that the EPC relates to the property that has the MPAN, not where the panels are located, since they could simply be on a ground mount attached to ..... well ..... the ground, not a building!

Can I be nosey and ask how much PV you have already, and what the sum of the inverters will be? Have you asked the DNO for permission if potential output would exceed 3.68kW?

Lastly, and this gets a bit complicated, but will the new system have better or worse generation (per kWp) than the older system. If similar or better, then you could consider sharing the TGM. I'll explain if you want, but if it's too far to cable (or re-cable) then it's not worth bothering about anyway.

Mart.

Hi Mart,

Thank you for your good wishes. Retirement is treating me well. Can't imagine how I found time to work before. The idea of extending the system comes from finding a suitable income from an endowment policy which has just matured. With current interest rates, and the annual limit on ISA investments it is difficult to make use of the money and get a guaranteed tax-free income. OK, I know I won't have the capital available once I've spent it on a PV system, but have worked this into my calculations.

I read through the really useful introduction you have written as the 'sticky' in this forum before I wrote the original post. Many thanks for all your hard work in writing it and keeping it up to date.

The current system is 2.96kWp, so yes, with an extra 2.6kWp I will be going over the 3.68kW and will therefore need permission. The proposed new system is likely to have a worse performance due to shading in early morning and late evening.

Whilst I'm writing, is anyone frustrated by having a generation meter which reads only the nearest whole kW? (My inverter is in the loft and not easily accessible to get a more accurate daily figure). If you have a generation meter which flashes 1000 times per hour for 1kW generation, for under £25 you can use a Velleman kit (I'm sure others are available) to read to three decimal places. Details available if needed.

Dave F

Martyn1981

Hiya Dave, thanks for the thanks - I've tried to slap 'extension EPC' warnings everywhere I could. Be interested to know if your FIT provider mentions it if you ask them for some general extension advice, since the REC's got new guidance in late July, and I personally rang MCS and EST to spread the word.

My original TGM is accurate to no decimal places, and not nearly as much fun as the extension TGM which goes to one decimal place.

Definitely sounds like you want a separate TGM then. Quick thought, is the shading big or little, as in, will it affect most panels at the same time, or be sporadic? I'm very pleased with my SolarEdge system on my extension since it gets shading from all and every direction, and would be next to useless if set up as one string.

I only ask, as being a garage, future access should be easier. SE power optimisers (PO's) come with a 25year warranty, but you do need to consider how accessible those extra bits of kit will be if one fails!

Mart.

Dave_Fowler

I've dropped an email to EDF explaining the situation and asking for advice on what permissions I need when adding the extra PV system.

I await their reply

Dave F

Dave_Fowler

Dave_Fowler wrote: »

I've dropped an email to EDF explaining the situation and asking for advice on what permissions I need when adding the extra PV system.

I await their reply

Dave F

EDF have replied to say that I would need MSC and EPC certificates. If the garage had a separate meter and address it would either require an EPC or exemption certificate. As the PV array belongs to and supplies the house, the certificate is for the house.

I went ahead and sent emails to nine local companies requesting quotations for the additional PV system to add to my current 2.96kWp system. Only three replied. One company took the details over the phone and sent a quote (subject to survey) without viewing the garage.

There is room for 12 standard sized panels only. Two companies said that there would be no problem getting permission from the DNO for a total of 6kWp on the house, but if I were to go to the smaller Panasonic panels and squeeze 16 panels in for a 4kWp system there may be problems with the DNO when the total is over 6kWp. Personally the price of these smaller panels can not be justified at the current FITs 4 - 10kW rate.

All companies have sent quotes for several different panel options Mono-Crystaline, Poly-Crystaline and Hybrid

The quotes were:-

1. 2.82kWp using Renesola PC panels £6069
2. 3kWp using JA Solar MC panels £6489
3. 2.88kWp using Panasonic H panels £8505
add £408 to the above quotes for Solar Edge P.O. and inverter

4. 2.88kWp using Komaes PC panels £5494
5. 3kWp using Kinve MC panels £5888
6. 3kW using Panasonic H panels £7532
I asked about Solar Edge but have received no reply

7. 3kWp using REC MC panels £8095
I telephoned this company saying they were well out of the playing as their price was so high. They asked what other quotes had been received so I said I was considering quotes between £5400 and £5800 including the Solar Edge system. I received:
8. 3kWp using Renesola PC panels and Solar Edge system £5800

I am tempted to go for quote 8.

Any comments on the quotations would be appreciated.

Edit: 4th company finally sent quote
9. 3kWp using Canadian Solar MC panels plus Solar Edge system £6413

Dave F

Martyn1981

Hiya Dave.

(PM sent).

Those prices aren't silly, but they just seem a little high to me, especially if scaffolding isn't needed.

SE kit probably is about £400 more (approx £500 for 12 PO's, but £100 or so less for the inverter).

This is real back of a fag packet stuff, but based on my system in July, and an other, I'd have hoped for about £5k including scaffolding for 3kWp. Perhaps a little more for 265W panels, such as YingLi.

Time is on your side now, the rate dropped last week (just a smidge), and I'd expect the companies to be quite quiet over Xmas. Also, as you'll know, generation will be low now for 3 months, so you could sit back and negotiate for a while, keeping the 1/2/13 review date in the back of your mind.

Who is your DNO? Have you tried ringing them for a friendly chat, just to see how things lie?

Mart.

Dave_Fowler

In the 'sticky' FAQ section at the start of the Green and Ethical forum, Martyn writes

For most properties (which have a single phase domestic supply) an application will have to be submitted to the DNO for prior approval, to exceed the 3.68kW limit. Your installer will need to complete a G83 stage 2 application, or a G59 application. Success is unlikely, and will almost certainly depend on you (and your neighbours) having individual supplies to each property. If you share a loop with your neighbour(s) then the DNO are much more likely to decline. Also, the DNO will take into account the number of other SSEG’s (small scale embedded generators) (PV, wind, hydro etc) in your vicinity that could potentially all be exporting at the same time.

Has anyone had a larger system accepted or rejected by their DNO. I've applied to the DNO for an extension of my system up to 5.96 kWp and am apprehensively waiting a reply.

Dave F

Fruit_and_Nut_Case

Dave_Fowler wrote: »

Has anyone had a larger system accepted or rejected by their DNO.

I have a 4kWp system and it was accepted without a problem by Western Power Distribution. I'm sure there are more folks around here with systems over the 16A limit.

EricMears

Fruit_and_Nut_Case wrote: »

I have a 4kWp system and it was accepted without a problem by Western Power Distribution. I'm sure there are more folks around here with systems over the 16A limit.

Our 4.00 kWp system was also passed (in July last year) without delay by WPD.

Martyn1981

Going back a year or so this area was open to interpretation, or even some ignoring. But it's getting tighter all the time.

Not sure if it was ever 'officially' OK, but 4kWp seemed to be passed as close enough.

Next we had kWp * inverter efficiency, so 4kWp combined with an inverter of 92% (or less) efficiency was fine.

Also have pseudo 3.68kW inverters that limit to 16A.

Now we have inverters that actually limit to 3,680W regardless of voltage, so at 253V they would limit to 14.54A. Or at 216V they might be pumping out 17A.

Next fun rule, which I don't think has come in yet, as I think it's still being discussed - any installer planning to install a sub 3.68kW system on the same sub-station as one (or more) they've previously installed, will need prior approval from the DNO. This is rather silly however, since the homeowner, in this situation, simply needs to find another installer who hasn't yet installed in that area. A new installer could then install without seeking prior approval, regardless of the number of existing SSEG's.

And of course, whilst all the DNO's should technically have the same rules, that doesn't mean they are all singing from the same hymn sheet.

Regarding DNO approval, whilst it's technically the same 'ballpark' they actually approve the inverter capacity, not the kWp of the panels. So in my case, they didn't approve the 5.58kWp of panels, instead I had to supply them with the model specs and G83 certificates of my inverters (easily downloadable) and got approval to export the sum of the inverters, which is 5.9kW. So I could now add more panels without additional approval, as long as I don't change the inverters (and assuming I had some space to fit them, which I don't).

This is fun isn't it!

Mart.