Upgrade of current setup SouthWest

Patrick MacLeay · Apr 13, 2015

Upgrade of current setup.
The current setup on my house is 14 Upsolar up240p polycrystalline panels at 105 degrees, feeding into a Fronius igtl3.0 inverter. It is ok but the power drops off after midday so I'd like to expand it. It was put in, in February 2012 so has the higher rate of FIT.

I have space at 190 degrees 3.7m long by 3.5m high enough for about 6- 8 more panels, and would like to replace the inverter with a dual MMPT 3.6kw one and expand the system to achieve a larger output throughout the day. We didn't do this in the first place as it's above a lean-to roof which requires scaffolding, but it's not too pricy to deal with now.
Will this be possible, and what is the implication on the FIT? Can I just declare the extra output of 3-3.6kw and be paid the new FIT rate on the 0.6 kw upgrade?
Also is there anyone in the southwest BA11 Frome area interested in taking it on? Please PM me if you're interested.
Many thanks - Pat

TedM · Apr 13, 2015

Your new system will be paid at the current FiT rate with the meter readings pro-rated between the two systems (assuming you go with a single inverter and meter). This means you could lose financially if the new panels do not produce pro-rata due to their orientation. Possibly not much, but it would be worth calculating so you know beforehand.

If you add 8 panels of 240W each then it will be an extra 1.92kW TIC, irrespective of the inverter output, for FiT calculation. The size of any replacement inverter will also need to be calculated with care. You will need DNO permission to go above 3.68kW.

Patrick MacLeay · Apr 13, 2015

Thanks TedM
I was afraid that might be the answer. I would not be looking to go over the 3.68 limit to preclude the requirement of notifying the DNO. I better get and estimate of what the extra income would be on the 1.92 kw, and go from there then.
Thanks
Pat

whinmoor · Apr 13, 2015

It's a bit awkward to do as you suggest as you would only have one generation meter which means that the total generation would be have to be divided on a pro-rata basis between the two arrays.

If you add 6-8 panels, you will be adding an extra 1.5kW (or more) of Total Installed Capacity. This will take you into the 4kW - 10kW bracket for ALL the added panels, not just the portion over 4kW.

From a technical point of view, all this would work with a 3.6kW inverter (go for an SMA or ABB Power One Aurora) but you might be better off having a completely separate second system using a small inverter. For this you would need to get your installer to make a G59 application on your behalf.

If you have shading issues on either roof, you really need a detailed site survey from someone who knows what they are doing.

whlphil · Apr 14, 2015

TedM said:
Your new system will be paid at the current FiT rate with the meter readings pro-rated between the two systems (assuming you go with a single inverter and meter). This means you could lose financially if the new panels do not produce pro-rata due to their orientation. Possibly not much, but it would be worth calculating so you know beforehand.

If you add 8 panels of 240W each then it will be an extra 1.92kW TIC, irrespective of the inverter output, for FiT calculation. The size of any replacement inverter will also need to be calculated with care. You will need DNO permission to go above 3.68kW.

Do you have this in writing Ted? I'm interested in doing this myself (although NPG have said I can't have more than 3.68 on my connection, the fronius 3.6TL I think could be stretched a bit further or I could swap out and replace with a Galvo which certainly could ) I was hoping to get round to looking at if we could do this sort extension but haven't had time to read the docs.

TedM · Apr 19, 2015

2.36. Where an installation is extended using the same technology, the original and extension can either be metered separately for generation payment purposes or metered together. Where the original and extension capacity are metered jointly, FIT payments will be made on a pro-rata basis based on the TIC of each part.

https://www.ofgem.gov.uk/ofgem-publications/94301/fitgeneratorguidanceversion8march2015-pdf