changing PV panels - effect on FIT?

[Tom]

Hi all - we're at a stage where we can get our PV panels back on the roof now. We have quite an old FIT so the rate is quite good, and the nominal installed capacity is 12kW I believe. The panels themselves are quite old and ratty looking - aluminium framed etc. I'm thinking it might be better to swap for some more up to date and efficient ones but am concerned re losing the FIT. I've asked Octopus who now manage our FIT for us, and they replied with:

 

 

*I’ve made a change to my installation. Do I need to notify anyone?*

You must notify your FIT licensee of any modifications to an accredited installation that increase or decrease its total installed capacity (TIC) from the same type of eligible technology (eg solar PV or wind).

This may happen by:

adding or removing generating equipment

replacing generating equipment with a larger or smaller TIC

You also need to notify your FIT licensee when:

a generation or export meter has been replaced, removed or begins measuring electricity that is not generated by the accredited installation

battery storage is connected to the accredited installation

there are any other modifications to the accredited installation

If you are the FIT generator of a ROO-FIT installation, you must also notify Ofgem of the changes by updating the installation’s registration on the Renewables & CHP Register. Ofgem will then review any changes before they are applied.

*For more information, see our Feed-in Tariffs: Guidance for renewable installations.*

*Will my accreditation be affected by repairing or replacing my generating equipment, and can I use pre-used generating equipment?*

You may repair or replace some or all of the equipment without affecting the accreditation of your installation, provided that the installation continues to meet the scheme rules. These include that:

the maximum capacity of 5 Megawatts (or 2 Kilowatts for micro-CHP) is not exceeded

the accredited installation continues to generate electricity from the same eligible technology

the accredited installation is not decommissioned or relocated

You may replace generating equipment with equipment that has formed part of an installation previously accredited under the FIT or Renewables Obligation schemes.

If, at any time, all of the plant forming the site up to the point of grid connection is removed, we will consider the accredited installation to be decommissioned and the accreditation to end.

If your installation was accredited under ROO-FIT, you must notify Ofgem of the modifications to the accredited installation and, if the TIC of the accredited installation also changes, your FIT licensee as well. Generators of MCS-FIT installations only need to notify their FIT licensee.

*For more information on modifications to accredited installations, see our Feed-in Tariffs: Guidance for renewable installations.*

*Can I extend the capacity of my installation?*

You can modify your accredited installation to either increase or decrease its capacity as long as the total installed capacity (TIC) of the installation and any extensions does not exceed 5 Megawatts (or 2 Kilowatts for micro-CHP).

However, you cannot receive FIT payments in respect of electricity generated from any additional capacity unless the extension was commissioned before 15 January 2016.

You must notify your FIT licensee of the modification, as well as Ofgem if the installation was accredited under ROO-FIT. If generation and export meters record electricity generated by both accredited capacity and non-accredited capacity, then payments must be prorated accordingly.

*You can read more about extensions and proration in our Feed-in Tariffs: Guidance for renewable installations.*

*I have recently replaced my generation or export meter. Do I need to tell Ofgem about it?*

If you are the generator of an MCS-FIT installation, you only need to notify your FIT licensee. If you have a ROO-FIT installation, you must also notify Ofgem of the changes by updating the installations registration on the Renewables & CHP Register. Ofgem will then review any changes before they are applied.

*I’m planning on getting a smart meter installed. How will this affect my payments?*

Your generation payments will not be affected. If you currently receive ‘deemed export payments’, then these will stop and you will instead receive export payments for the amount of electricity recorded by the meter exported to the grid.

‘Deemed export payments’ are paid when installations have a capacity under 30kW with no export meter, or where the electricity exported cannot be properly measured. These payments are based on an estimate of the amount of electricity the installation exports to the grid. The amount of electricity that is deemed to be exported is fixed at a percentage of the generation of the installation. That percentage is set each year by the Department for Energy Security and Net Zero.

*I want to add battery storage or an electric vehicle charging station to my property. Will this affect my payments?*

As long as your electricity generation (and export, if on metered export) can still be accurately measured, your payments will not be affected. However, if it can’t be, you can’t receive payments for that electricity.

You must be able to measure the electricity generated (and exported, if applicable) by the installation separately from all other sources to receive generation payments (and export payments, if metered).

 

 

So, it looks like I can swap the panels but will need to inform the FIT licensee (who's that?) - highlighted red. It seems like I can also increase my generating capacity - highlighted blue, but wouldn't receive any FIT payments for this.

The thing is, if my installed capacity is 12kW, it has rarely, if ever, generated at this level - perhaps even more so now that the panels are 10yrs old+. Would I be OK to replace the panels and ADD some extra to bring it up to this figure?

 

Any guidance here gratefully received!

Cheers

Tom

[MikeGrahamT21]

The licensee is Octopus in your case.

 

im not sure how they pro-rata the payments for generation, but it must be some standard equation they apply. I know these rules did get updated recently to account for failing equipment etc.

 

the important thing here is the rated capacity, if you swap out current panels with brand new ones totalling up to the same capacity then in theory nothing should change and you’ll get paid for everything you generate, in theory, but it’s all a bit of a grey area and you’ll find that ofgem has one set of rules, and your licensee is allowed to interpret them in their own way so could be quite different.

 

the change of equipment I believe has to be approved by both ofgem and the licensee so you should be able to find out what changes if any before placing any orders.

[Tom]

Thanks @MikeGrahamT21, I'll speak to Octopus and try and get it from the horses mouth

[Dillsue]

If you swap out the panels like for like ie remove 12kwp and install 12kwp then you don't need to notify anyone. Its only if you change the capacity that you need to notify your FIT payer.

 

If you don't think your array is generating correctly you probably want to investigate that rather than shelling out for a new set of panels. Our FIT system from 2015 is still generating like new.

 

 

[Dillsue]

6 minutes ago, Tom said:

Thanks @MikeGrahamT21, I'll speak to Octopus and try and get it from the horses mouth

Google FIT Guidance for Generators and look at the section on alterations- that's the OFGEM guidance which is the horses mouth

[MikeGrahamT21]

10 hours ago, Dillsue said:

Google FIT Guidance for Generators and look at the section on alterations- that's the OFGEM guidance which is the horses mouth

 

As above, the licensee is allowed to interpret the rules in their own way, i've been through all this before between ofgem and british gas, and ofgem specifically told me that their guidance is open to interpretation and not enforced as such.

 

This is the current guidance to licensees: https://www.ofgem.gov.uk/sites/default/files/2024-04/FIT Guidance for Licensed Electricity Suppliers V17.pdf

 

However, this is what i got from Ofgem: The decision ultimately lies with the FIT Licensee in accordance with this guidance.

[ProDave]

My reading is if you are not changing the total installed capacity you don't have to do anything.  So new panels of broadly similar size to the old and operating with the same original inverter I would just do it.

[joe90]

If your inverter sends the same output does it matter what the panels generate? (And who is going to notice you changed them?) can you measure the drop in efficiency you perceive? Aluminium frames can be polished/paintec.

[MikeGrahamT21]

9 minutes ago, joe90 said:

If your inverter sends the same output does it matter what the panels generate? (And who is going to notice you changed them?) can you measure the drop in efficiency you perceive? Aluminium frames can be polished/paintec.

 

Someone comes out to view the system physically, including the meter once every 2 years, guy came here about 2 weeks back

[Tom]

43 minutes ago, joe90 said:

Aluminium frames can be polished/paintec.

Aaagh, there are 56 of the buggers!

 

Just had a look at the panels, they are just about 1.66m x 0.99m and the max output is 240W - so 146W/m2

 

The cheap panels on the City Plumbing site are 1.94m2 and produce 410W max - so 211W/m2

 

I have 56 panels, so max conceivable output would be 13.4kW - which could be achieved with 33 of the new panels (area: 93.5sqm vs. 64sqm).

 

As above, bit wary of how Octopus might interpret the rules, so will need to confirm with them before doing anything

 

[joe90]

But again your output to the grid is controlled by the inverter(s) surely so it does not matter what output your panels are ? (Please correct me if i am wrong).

[ProDave]

4 hours ago, MikeGrahamT21 said:

 

Someone comes out to view the system physically, including the meter once every 2 years, guy came here about 2 weeks back

On the rare occasions that happens, they have only been interested in looking at the meter to confirm the serial number and confirm a real up to date reading.  They never even looked at the inverter (in the garage) or looked up at the panels on the roof.

 

Since Covid no meter reader has been, we were instead asked to send a photograph of the meter.

[Dillsue]

6 hours ago, ProDave said:

On the rare occasions that happens, they have only been interested in looking at the meter to confirm the serial number and confirm a real up to date reading.  They never even looked at the inverter (in the garage) or looked up at the panels on the roof.

 

Since Covid no meter reader has been, we were instead asked to send a photograph of the meter.

Same for us

[Dillsue]

9 hours ago, joe90 said:

But again your output to the grid is controlled by the inverter(s) surely so it does not matter what output your panels are ? (Please correct me if i am wrong).

If you increase the size of the array it'll generate more over the year. May may not be clipped in the summer but total annual generation will go up. Whether your FiT payer notices or cares is anyone's guess.

[Dillsue]

10 hours ago, Tom said:

Aaagh, there are 56 of the buggers!

 

Just had a look at the panels, they are just about 1.66m x 0.99m and the max output is 240W - so 146W/m2

 

The cheap panels on the City Plumbing site are 1.94m2 and produce 410W max - so 211W/m2

 

I have 56 panels, so max conceivable output would be 13.4kW - which could be achieved with 33 of the new panels (area: 93.5sqm vs. 64sqm).

 

As above, bit wary of how Octopus might interpret the rules, so will need to confirm with them before doing anything

 

If you've got 13.4kwp of panels, run your figures through PVGIS to see what you should be generating. If you're around the forecast there's no point in changing your panels. Our 9 year old 250 watt panels are generating like new.

[Tom]

Thanks @Dillsue, guess I'm just thinking aesthetics too.

I've managed to dig out the MCS certificate and it looks like our Total Installed Capacity is 16kW and our Declared Net Capacity is 12kW. Does this potentially mean I could replace what's there and add panals up to a maximum 16kW and still get the FIT up to this amount?

[MikeGrahamT21]

9 minutes ago, Tom said:

Thanks @Dillsue, guess I'm just thinking aesthetics too.

I've managed to dig out the MCS certificate and it looks like our Total Installed Capacity is 16kW and our Declared Net Capacity is 12kW. Does this potentially mean I could replace what's there and add panals up to a maximum 16kW and still get the FIT up to this amount?

 

Don't replace based on aesthetics, thats an awful waste in an already wasteful world. When they're on the roof you don't really see them anyway unless you specifically look.

[Dillsue]

11 hours ago, MikeGrahamT21 said:

 

Don't replace based on aesthetics, thats an awful waste in an already wasteful world. When they're on the roof you don't really see them anyway unless you specifically look.

Absolutely

[Dillsue]

11 hours ago, Tom said:

I've managed to dig out the MCS certificate and it looks like our Total Installed Capacity is 16kW and our Declared Net Capacity is 12kW. Does this potentially mean I could replace what's there and add panals up to a maximum 16kW and still get the FIT up to this amount?

AFAIK you can only change like for like so if you've got 13.4 kwp now you'd need to replace with the same capacity. If you want to do something different then read the guidance to understand what total and net capacity means and how it would affect payments.

[Tom]

21 hours ago, MikeGrahamT21 said:

 

thats an awful waste

Not if I sell the old panels and they're reused elsewhere

[Andehh]

OP, I'm in the same boat. 4kw design made up of 21 individual panels from around 2012. We removed and refitted like for like over our build, and could more then double our output just replacing old for new.

 

However our FIT is worth about 60p/kw so worth around £2000 a year, and I'm too scared to risk loosing it for the extra 4-5kw our roof could take.

[joe90]

As I posted earlier PV output is restricted to current output by the inverter, it’s implied by the above that total output is limited but I don’t get that as surely the DNO will want whatever it can get (but limited by current at any one time.) I,e someone with a split array (east, south, west) will give greater output over longer periods of time but may have the same number of panels as someone else only facing South. Please explain.

[SteamyTea]

9 hours ago, joe90 said:

restricted to current output by the inverter

 

9 hours ago, joe90 said:

Please explain.

There are a couple of things going on.

While the power may be limited by the inverter, that power could be higher at the wrong time i.e. around noon.

This can cause the local network to increase in voltage until it hits the limit, this can cause problems.

Then there is the energy side. DNOs have to manage energy flow over a half hour period, if there is a lot of micro generation over supplying unexpectedly, then the planned delivery may be wrong, this costs money, and DNOs hate paying out.

Taking a bit of an example, say 10 houses are all at the G98 limit on the local substation. Then say 4 up capacity by 20%, but still let the inverter limit to the 16A.

In a sunny autumn morning, there may have been 10 kW being pumped in, now it would be 10.8 kW.

Now that should be perfectly manageable, but if 50 houses did it, problems may arise (mainly the local voltage).

This basically comes down to the National Grid being designed for central generation, and not distributed local generation.

 

In some ways micro PV is better than micro wind generation and it reacts slower.

Having worked on a micro turbine (5 kW), it is amazing how hard they work the inverter. Not unusual for the turbine to hit auto stall speeds as the inverter is playing about with the MPP algorithm.

[joe90]

6 minutes ago, SteamyTea said:

While the power may be limited by the inverter, that power could be higher at the wrong time i.e. around noon.

Great explanation but I thought the only stipulation was the 16 amps, I have not seen anything where timing has been mentioned. I know the local network must be able to cope with the predicted input which is why some are charged for upgrading their local transformer. Again my point is if I were limited to 16 amps (at any time) having more panels would still give the network the max 16 amps controlled by my inverter (or am I bring thick 🤷‍♂️)

[joe90]

16 minutes ago, SteamyTea said:

Then say 4 up capacity by 20%, but still let the inverter limit to the 16A.

In a sunny autumn morning, there may have been 10 kW being pumped in, now it would be 10.8 kW.

Surely if the voltage is the same and the current limit is the same more panels would not give a rise?

 

only asking because I don’t know but want to.

Edited April 27 by joe90