Adding extra PV using same inverter

[Gavin A]

Fit payees only acknowledge inverter size and have no interest in the amount of panels on your roof.

Not according to Ofgem unfortunately since 2012 or so.

the fit rate is determined by the nominal kWp rating of the panels.

The op could add panels to this system, but the new additions would be in the 4-10kWp fit rate, and the generation figures would have to be determined proportionally if using the same inverter.

 

[Gavin A]

But that is not right considering the inverter will never exceed its rating.

So you believe installing 5kW of solar panel on 3.6kW of inverter will produce 5kW of AC?

working on small scale installs such as 50kW inverter I install 55kW is solar panel MCS and this receives <50kW fit. On 150kW I install 150kW of inverter and install 165kW of solar panel and claim <150kW Roofit tariff.

When you discuss export loads with the DNO you always quote DNC as the export AC load being the inverter. ENWL understand this and were the first to acknowledge the fact, all other DNO have followed suite and FIT payees are only interested in the DNC not the amount of panels.

You sir with all due respect are wrong.

we've had long discussions with ofgem on this point, and nearly took them to judicial review, but didn't have the money.

The guidance has been pretty unequivocal on this for at least the last couple of years. Though I entirely agree with your line of argument, unfortunately Ofgem don't agree.

 

[akaPABLO]

Yes, the guide is very clear. I declare 200 panels on a 50kW inverter system, you are correct...how was I mistaken?

 

[SibertSolar]

Pablo - you wouldn't be the first to point out the inconsistencies in the understandings of TIC/DNC definitions and Ofgem's stances on this, and how it relates to the UK's FiT framework, and how that framework is designed etc.

As has been advised already, the FiT bandings are based on kWp values of the PV installation, not kW output of the SSEG. TIC and DNC only differ, from a definition point of view, by the amount of losses in the "plant". Ofgem have always declined to define the term "plant" when I have asked them to do so. You can quite rightly declare the peak kW output of the inverters when advising DNC but that in itself it not strictly true to the definition of DNC in Ofgem's eyes - although you have very little else to work from. However, when registering the system under the FiT scheme, you must declare the TIC of the PV modules installed, regardless of what the expected yield, or peak output, of the system might be. Doesn't particularly make much sense, granted, when looking at east/west splits (for example), or intentionally under-sized systems where the DNC falls just within a tariff band that would allow a higher FiT rate, but that's the way it has to be under the current framework.

Don't forget also that the limit for deemed 50% export here in the UK is set to 30kWp - that's the TIC of the modules, not the nominal peak AC output of the system. That in itself is another example of the errors in the framework - a FiT-related design limit linked to peak export to the national grid, based on peak DC capability of the array under STC.....dumb.....

 

[akaPABLO]

The amusing thing is that DNC determines MCS accreditation against Roofit accreditation. So 55kWp of solar with 50kW of inverter can obtain a MCS with >50kW tariff band???

ill stick to my formula as this yields more kWh annually then standard...

thank goodness i can install 300kW in three stages the first being 150kW with immediate extension a further 100kW and finally a cheeky MCS 50kW

do you think all solar sites will ever have their roofs audited?

 

[SibertSolar]

Yes, 55kWp of PV modules will be >50kWp FiT band, regardless of the peak output of the inverters.

No, I don't think all sites will be audited.

What do you mean by "your formula" though, out of interest?

 

[TedM]

@akaPABLO - I hope you have plenty of cash put aside to compensate your customers who have been wrongly advised/declared/registered when OFGEM catch up with them.

I have been involved with the same discussions with GavinA. Technically OFGEM are 100% wrong but they will not change their stance as they believe that this is the way that the FiTs was "intended" to work.

 

[akaPABLO]

How is deployment measured with regards to targets met and follow on if not met, the TIC or the DNC?

plenty of cash? I'm lucky to pick up a wage at the end of the week don't you worry about my clients they are very well looked after.

For the record ofgem if you happen across this: kiss my photon you jobsworth, I'm sure we will lock horns in the future again. Also as I've told you before please process Roofit applications quicker so I can take advantage of the extension loophole at a faster rate.

 

[Gavin A]

The amusing thing is that DNC determines MCS accreditation against Roofit accreditation. So 55kWp of solar with 50kW of inverter can obtain a MCS with >50kW tariff band???

nope. Though you're right about the anachronism in DNC determining if it's MCS or Roofit.

ill stick to my formula as this yields more kWh annually then standard...

Are you actually putting different TIC figures to the DNC figures on the MCS cert? I'm surprised that's not getting picked up, I suspect it will do at some stage. If not then you're risking fraud charges / being struck off the MCS register / being sued for the lost revenue if a system ended up classified as being in the 50-150kWp FIT band rather than the 10-50kWp band.

thank goodness i can install 300kW in three stages the first being 150kW with immediate extension a further 100kW and finally a cheeky MCS 50kW

do you think all solar sites will ever have their roofs audited?

You really are risking a fraud charge for that if you're talking about the same site, and you're on about the last 50kWp system being done on the 0-50kWp FIT rate. Or at best, being sued for loss of earnings / misrepresentation by clients who find part or all of their system being paid at the 250kWp + FIT rate rather than what you promised them.

It may take a while to happen, but this sort of stuff is subject to audit, and action can be taken retrospectively to reclaim FIT overpayments (and even ban system owners from the FIT scheme entirely). All sites are having their meters read every couple of years, and it's not going to take much for Ofgem to add up the total capacity installed at an MPAN and work out it's actually over 250kWp.

Ok if you're intending to be fly by night and out of the industry in 18 months or so, otherwise you're building yourself up for major problems at some point in the future.

Tbh I really don't see why you feel the need to do it on these big commercial roofs. We have no problem at all in making the economics stack up well for our clients on the bigger roofs up to 250kWp, and I'd not risk that business by recommending the above approach to attempt to squeeze another 50kWp in on top. Put it this way, if we were competing with you for that work the client would be left in no doubt that you'd just recommended they attempt to defraud the FIT scheme.

Trust me on this, this can and will come back to bite you. Luckily for us we had it happen on a 4.25kWp system restricted to 3.68kW AC output, and the situation was resolved by just removing a single panel and compensating the customer proportionately. The costs involved if that happened with 5kWp extra on a commercial roof, or 50kWp extra would far outweigh the level of increased work or profit margin likely to be made by doing it. We had the legitimate excuse that we were following the rules as they were written, you don't have that excuse any more.

Unless you have £15k or so in the bank ready to launch a judicial review of Ofgem's interpretation of the FIT legislation, you really want to take a long hard look at the reasons you're doing this, and whether the risks involved are worth it IMO.

Your call of course, but don't say nobody had warned you about the risks you were taking.

 

[akaPABLO]

nope. Though you're right about the anachronism in DNC determining if it's MCS or Roofit.

Yup. Fit level is measured by TIC but the MCS and RooFiT accreditation are measured by DNC. So why have two ways of measurement and not use TIC as the only accumulative sizing. What is the point of DNC, is it's sole purpose to help calculate total deployment only?

Are you actually putting different TIC figures to the DNC figures on the MCS cert? I'm surprised that's not getting picked up, I suspect it will do at some stage. If not then you're risking fraud charges / being struck off the MCS register / being sued for the lost revenue if a system ended up classified as being in the 50-150kWp FIT band rather than the 10-50kWp band.

Easy cowboy! Im not sure what you are suggesting here? Fraud? Whaaoooo son. I think we need to assess the governments ruling definition of TIC and DNC as let's face it Ofgem are a mere puppet using this guideline to grant accreditation.

"the maximum capacity at which an Eligible Installation could be operated for a sustained period without causing damage to it (assuming the Eligible Low-carbon Energy Source was available to it without interruption), a declaration of which is submitted as part of the processes of ROO-FIT Accreditation and MCS certified Registration."

we all know a solar pv will operate at less <20% of panel to inverter so for example 68 panels @ 250 coupled with 17000 sma will have a TIC of 13.6. We then have another 68 panels on anothe 17000 sma with a 15000 sma @ 12 giving us a TIC of 39.2kWh. So the 200 solar panels will at maximum only generate 39.2kW TIC with 49kW DNC

You really are risking a fraud charge for that if you're talking about the same site, and you're on about the last 50kWp system being done on the 0-50kWp FIT rate. Or at best, being sued for loss of earnings / misrepresentation by clients who find part or all of their system being paid at the 250kWp + FIT rate rather than what you promised them.

Hehe, I think you are misinterpreting my planned action but I'll play along. A question: Is there anything wrong with making multiple applications with different registered bodies. So for example if I process an MCS application of say 50kW receiving a 50 tariff then immediately process a 100kW application extension with Roofit to claim the 150 tariff then immediately thereafter process a 100kW application with Roofit to claim the <250 tariff?

It may take a while to happen, but this sort of stuff is subject to audit, and action can be taken retrospectively to reclaim FIT overpayments (and even ban system owners from the FIT scheme entirely). All sites are having their meters read every couple of years, and it's not going to take much for Ofgem to add up the total capacity installed at an MPAN and work out it's actually over 250kWp.

I don't think they would have a clue, multi orientations versus perfect pitched angles with tier 1 panels versus Chinese. These folks are pen pushers the only thing they will be looking at is meter versus meter reading and inverter rating. Remember this is rooftop you're talking about City folk with clip boards.

Ok if you're intending to be fly by night and out of the industry in 18 months or so, otherwise you're building yourself up for major problems at some point in the future.

big man, I have been installing since NASA put the first panel in space and I'll be around for a while longer, only major problems I have is that ****ing solarmax

[/QUOTE=Gav]Tbh I really don't see why you feel the need to do it on these big commercial roofs. We have no problem at all in making the economics stack up well for our clients on the bigger roofs up to 250kWp, and I'd not risk that business by recommending the above approach to attempt to squeeze another 50kWp in on top. Put it this way, if we were competing with you for that work the client would be left in no doubt that you'd just recommended they attempt to defraud the FIT scheme.[/QUOTE]

because the electric companies are lying thieving shistas. Do you understand how much control they have on the feed in tariff and how they police the pot of gold that everybody contributes to if you buy electricity? Lol these lying scum bags that pay out the feed in tariff to overseas investors keep any surplus undeclared annually, oh then they back the scum in parliment by donating to their campaign fund.

[/QUOTE=Gav_the_Impaler]Trust me on this, this can and will come back to bite you. Luckily for us we had it happen on a 4.25kWp system restricted to 3.68kW AC output, and the situation was resolved by just removing a single panel and compensating the customer proportionately. The costs involved if that happened with 5kWp extra on a commercial roof, or 50kWp extra would far outweigh the level of increased work or profit margin likely to be made by doing it. We had the legitimate excuse that we were following the rules as they were written, you don't have that excuse any more.[/QUOTE]

[/COLOR=RED]talk about pot and kettle son[/COLOR]

[/QUOTE=Gav]Unless you have £15k or so in the bank ready to launch a judicial review of Ofgem's interpretation of the FIT legislation, you really want to take a long hard look at the reasons you're doing this, and whether the risks involved are worth it IMO.[/QUOTE]

[/COLOR=RED]lol, Ofgem hold no weight and only interpret the written guidance. They have no power to change this and will do anything to screw all applicants out of a higher rate of tariff. If I mentally picture Ofgem I see that scene from pulp fiction, you know Z in the leathers pretending to have all the power but really they are sweat shop employees.[/COLOR]

[/QUOTE=Gavin_A]Your call of course, but don't say nobody had warned you about the risks you were taking.[/QUOTE]

[/COLOR=RED]there ain't no risk baby, I'm in total control.[/COLOR]

DISCLAIMER: i do not give permission for any of this text to be used as a case for prosecution please read the terms and conditions of this forum or you will be sought through the highest courts in this land and sued for your entire piggy bank!

 

[TedM]

We have both TIC and DNC in FiTs because neither DECC nor OFGEM understand the technology at an engineering level. They are historical terms taken from large power station legislation that are plain unnecessary in FiTs.

That tariff bands are based on TIC and the MCS threshold is based on DNC is a prime example of this. The disconnect between FiT and G83 is another. That PV TIC is calculated on panel kWp at STC times the number of panels is yet a third.

 

[Gavin A]

your choice akapabo, but you are going to come a serious cropper and probably end up bankrupt as a result at some point if you're not talking hypothetically.

why risk it, for what?

Hehe, I think you are misinterpreting my planned action but I'll play along. A question: Is there anything wrong with making multiple applications with different registered bodies. So for example if I process an MCS application of say 50kW receiving a 50 tariff then immediately process a 100kW application extension with Roofit to claim the 150 tariff then immediately thereafter process a 100kW application with Roofit to claim the <250 tariff?

No I don't think I was misinterpreting what you said, you were clearly talking about installing 300kWp of panels with the final 50kWp on MCS (quoted below), you're now talking about a different scenario, which is still outside of the rules, but a bit less so.

thank goodness i can install 300kW in three stages the first being 150kW with immediate extension a further 100kW and finally a cheeky MCS 50kW

do you think all solar sites will ever have their roofs audited?

An entire 300kWp system ending up being accredited at the 6.16p FIT rate rather than the mix of 11.71p, 9.96p, and 9.64p per kWh is a hell of a loss of revenue, no client is going to take that lying down on a £250k investment, and no insurance company would cover you for that sort of attempted fraud (which clearly is what that would be).

Your PI insurance may possibly cover you against being sued for giving bad advice in the 2nd scenario you outline, but it's still pretty clear that you're not following the guidance, so they could well leave you high and dry to defend yourself / settle with the aggrieved client.

Here's the relevant sections of the Ofgem FIT suppliers guidance, they're clear that what you're suggesting in the 250kWp scenario should be treated as being a single 250kWp installation. It's not a loophole you'd be using, it'd just be fraud that you're hoping to get away with. Tbh I'm trying to work out if you're just on a wind up here, if so, well done, if not, then enjoy it while it lasts, but for the next 20 years you run the risk of one or more of these installs coming back to bite you with serious financial consequences if it does.

7.2. Multiple installations of the same technology type commissioned on the same date on the same site will usually be regarded as one installation. Such an installation will have one tariff rate based on the total installed capacity of all installations. The same generation meter can be used to record the amount of electricity generated from all installations.
7.3. Multiple installations of the same technology type commissioned at different times but on or before the application date on the same site will usually be regarded as one installation. Such an installation will have one tariff rate based on the total installed capacity of all installations. The same generation meter can be used to record the amount of electricity generated from all installations.
7.4. Generation and/or export meters which serve more than one accredited FIT installation are permitted, as long as only installations eligible to receive generation payments are connected to the meter.
7.5. All accredited FIT installations sharing the same meter should be registered with the same FIT Licensee. To ascertain whether there are any installations on one site sharing the same meter, FIT Licensees should search for other installations at the same address. If a match is found and they are not the FIT Licensee of the match, the FIT Licensee is required to contact the CFR Team.

lol, Ofgem hold no weight

They're only the organisation that processes the RooFIT applications, and issues the guidance that all FIT suppliers have to follow, and regulates them to ensure they do. They only have the power to withhold all FIT payments from your clients or determine that they should be paid at a lower rate inline with their guidance. At that point what do you think your client is going to do? Instruct their lawyers to take Ofgem to court for implementing their clearly stated rules, or instruct them to take you to court for giving false advice?

This really is a been there done that kinda thread, with several thousand wasted on legal costs to attempt to argue the point on FIT ratings being based on the inverter output not panel ratings, before realising that I'd need another £10-15k to take it to judicial review. Your funeral if you choose to ignore the advice that's born of bitter costly experience.

I'll come back to my opening point - why risk it, for what advantage to you? There's more than enough work out there on commercial roofs playing by the rules, the returns are already incredibly good for most commercial roof mounted systems, what's the point in opening yourself up to that level of additional risk?

 

[akaPABLO]

Well done Gavin A, why should I take the risk?

do you fancy commissioning some pv, I'll make it worth your while :

 

[whlphil]

This has been one of those questions Ive been asked over and over and Worcester and Gav are right FiT is determined by TIC

Grid connection is determined by DNC

Gav is also right on the 300kW site size, from bitter experience I can tell you that if you have a 50kW and extend by 50kW, even after a year, then the second 50kW is given the current rate for a 50-150kW tariff NOT a 50kW - hence your 300kW scenario would be classed as a 300kW install and receive 6.16p

On TIC;

Theres a great response to this question here from a freedom of information request to DECC https://www.whatdotheyknow.com/request/determination_of_method_of_calcu?unfold=1#incoming-437874

With a further clarification on another freedom of information request to DECC as to why TIC was taken as the determining factor here https://www.whatdotheyknow.com/requ...d Capacity Ted Marynicz October 2013.pdf.html

 

[The Solar King]

What about the thread starters original question?

Depending on which direction the original array faces, extending it is entirely possible. If you can obtain matching panels, life would be easy. We have done a 6kW west facing system attached to a G83 limited inverter. Simulation showed very little risk of clipping in the middle of the day in mid summer. (in Edinburgh).

Unless you are on the south coast, you will probably be OK with 5.5kW facing south. The fall in the price of inverters means it may be worth while buying a new twin tracker and putting the additional panels on the second MPPT.

You reallly need advice from someone local to you who is willing and able to do the calcs for you.