New OFGEM FIT policy released yesterday

[John_S]

I don't understand why improved panel efficiency is an issue in replacements.

The criteria is that the TIC capacity is unchanged. The fact that panels are more efficient only means that the area of the panels will be less.

For example, In 2010, I installed 10 Sanyo/Panasonic panels of 210W each giving a TIC of 2.1kW. These are 1,600mm*800mm giving a total area of 12.8 sqm. This is 164W per sqm.

I could replace them with 5 REC Alpha Pure-R Series 420W panels (from ITS) which have a panel efficiency of 218W per sqm and only take up 9.6 sqm of roof space or 5 JA Solar Mono MBB PERC LR Half-Cell panels (if ITS had them in stock) which would take up 10 sqm of roof space.

As far as FITs are concerned, I would have neither increased nor decreased my TIC.

[shirehorse99]

ok - thanks resybaby and everyone else I know fully understand - I think - my 8 new panels that I have ordered will replace the 14 old panels - but I have the space to place another 6 panels on a separate AC coupled inverter to charge my batteries

[resybaby]

I don't understand why improved panel efficiency is an issue in replacements.

The criteria is that the TIC capacity is unchanged. The fact that panels are more efficient only means that the area of the panels will be less.

For example, In 2010, I installed 10 Sanyo/Panasonic panels of 210W each giving a TIC of 2.1kW. These are 1,600mm*800mm giving a total area of 12.8 sqm. This is 164W per sqm.

I could replace them with 5 REC Alpha Pure-R Series 420W panels (from ITS) which have a panel efficiency of 218W per sqm and only take up 9.6 sqm of roof space or 5 JA Solar Mono MBB PERC LR Half-Cell panels (if ITS had them in stock) which would take up 10 sqm of roof space.

As far as FITs are concerned, I would have neither increased nor decreased my TIC.

It isnt John, efficency isnt a consideration at all - providing you dont increase or decrease your TIC above your existing FIT contracted number.

Your example would mean you dont have to advise either. Like me and Shire. The physical sizes etc are irrelevent to it all.

[Fueltheburn]

This has been a most interesting read.

I have panels spare rated at 405W
The original system is a 3kW system with 12 x 250W panels.

To replace mine with 8 x 405W would equal a panelling of 3.24kW.
Would this mean I am outside of those rules due to over-panelling or would the 3kW inverter be the key here?

[resybaby]

This has been a most interesting read.

I have panels spare rated at 405W
The original system is a 3kW system with 12 x 250W panels.

To replace mine with 8 x 405W would equal a panelling of 3.24kW.
Would this mean I am outside of those rules due to over-panelling or would the 3kW inverter be the key here?

You would need to contact your FIT people (as TIc increased from 3kw to 3.24kw) and follow whatever they say. If panel kw stays exactly the same there is no obligation to advise. Inverter is irrelevent really.
But whilst you should be ok with the 'repowering' element of changing things and earn more cash due to efficentcy improvements provided by the newer panels, they would likely want to apportion your payments due you because of the original FIT being only 3kw and the new one larger. Think this was similar under the previous rules?

So something like a future payment based on 92% of your future measured new panel output (i.e. 3 divide by 3.24).

But id give then a call/email to be 100% beforehand, rather than just do it

[Fueltheburn]

I see the legitimate side of this
The real question is how likely are they to notice a 0.24kW gain ....

Previous panels were polycrystalline just over 12% efficiency.

[Fintray]

I see the legitimate side of this
The real question is how likely are they to notice a 0.24kW gain ....

Previous panels were polycrystalline just over 12% efficiency.

Depending on the panels the new ones could be almost twice this efficiency.

[wookey]

I've been looking at this as I currently have scaffolding up. I currently have 2.88kW (16x180W Sharp NU-180E1).

I can get 14 425W panels on the roof instead: (5.59kW). And it's dead easy to connect the 1st 6 up to the existing inverter, but that's 2.55kW so 11.5% less than existing. Or 2975 (+3%). So that doesn't work too well on the 'just make it the same size so I don't have to notify' front. I do wonder why they require notification for reductions. If I'm OK with getting 11.5% less that should be fine with the FIT principles. And I do wonder whether anyone will even notice - it's as if one of your panels stopped working, which could happen (and probably does regularly on micro-inverter systems, and no-one comes knocking).

Has anyone tried just reducing the capacity a bit without notifying? I bet nothing happens. It's a 2010 system, so still has 10 years to run.

5 of the JAsolar 570W panels would get much closer at 2850W which is 1% different.
In fact if I want to keep close to the 2880W TIC I can do:
5*570W=2850W
6*470W=2820W
7*410W=2870W

So (after some boring arithmetic) it looks like my best plan for an easy life is probably some Longi LR5-54HPB-410M. I can fit 14 on the roof for 5.74kWp and allocate half to the existing FIT inverter for only 0.5% difference from TIC.
Need to check the voltage and current strings work. GBP 661 for the panels plus sundries (and a new inverter)
I could have a prettier layout and another 250W or so if I had a free choice of panel outputs/sizes but this will do (it's on the back of the house so I don't really care what it looks like).

Will new panels of this type of nominal 2870Wp actually produce significantly more (or less) output than nominal 2880Wp 2010 panels (e.g. because of better low-light performance or other variations?) I've not been keeping up with details of PV cell tech over the last 15 years.

[Fueltheburn]

Been away for a while.
Before I left though, phoned several places for an official clarification on this.
I phoned MCS and OVO and they seemed oblivious to this official release. MCS stated that they had no bearing on the implementation of the rules and told me to phone my FIT provider.
Sooo, I phoned my FIT provider and they also said it wasn't anything to do with them. End result for me, is it seems Ofgem may be the only ones who may be interested in any changes.

[resybaby]

Id be inclined to check that with your FIT supplier Wookey before doing anything, given you cannot match the existing TIC exactly, although very close to being 'equal' to your existing contract numbers, you would need to advise then given my understanding of the new policy.

The trouble is that they may then keep an eye on what you do once you raise your head above the radar. But at least you would be in compliance with the notification side of things, and your new eventual capacity (up or downwards) should just get apportioned then and payments adjusted accordingly.

You could just change things of course and take the risk they'd not notice - which they probably wouldnt when just comparing ongoing meter readings with previous ones, after all there must be quite some latitude in what they expect from people in terms of readings/generation, given the variables in the weather (which we can see is often quite a bit from folks monthly readings on here), and of course the fact that you (cough) could have 'cut that big tree down in your garden' that has been shading the original system for all those years, or fixed those pesky optimisers that had unknowingly broken.

its a tough call making that decision as the last thing youd want to do is impact the 2010 and risk losing it.
The FIT contract of old (and new) provides for random selected audits of 8nstallations.

Personally, id not risk it. As if caught 'fiddling' things you can be booted off the contract, never to get back on again.

Id ask first and get everything in writing. You may be able to bung on loads of panels then of your choosing and just get your installation simply 'apportioned' and keep things all 100% legit.

Only hiccup is will they respond quick enough to take advantage of the existing scaff being up.