Newbie Question - Cap on back to grid?

Nalz

Hi folks,

If this information is staring me in the face I apologise, however I don't seem to to notice it anywhere...

If you have solar panels, is there a cap on the amount you get selling energy back to the grid? I've heard conflicting info on this and it's not the easiest thing to search online, at least not for me!

Thanks

con747

https://www.boards.ie/discussion/2058286057/newbie-question-cap-on-back-to-grid

The only cap I know of is the tax free up €200 for domestic installs with up to a 6kw inverter after that you should declare it as income.

Nalz

Thank you.

Was there a cap once upon a time do you know? I've a neighbour with 8 pv panels telling me you must buy a battery as after 250 euros you give all back to the grid for free.

con747

https://www.boards.ie/discussion/comment/120292694#Comment_120292694

I don't know what your neighbour is on about, so I wouldn't buy a battery unless you do the maths to see if you need one. Personally I think batteries are a benefit for various reasons but it's a case by case basis. Members here have received more than €250 from suppliers. I think your neighbour might not know the full facts. Post #2205 here is an example https://www.boards.ie/discussion/2058094040/pv-feed-in-tariff/p74

slave1

You can export as much as you want, the only restriction is related to which paperwork you have filed with esbnetworks, 99% of us will have filed a NC6 form so we should be exporting no more than 6kW instantaneously, however unless you have a Smart Meter the esb will never know your instantaneously export rate.....the tax implications are irrelevant

Jonathan

https://www.boards.ie/discussion/2058286057/newbie-question-cap-on-back-to-grid

Is your friend a farmer? TAMS (II?) grant aided systems are not permitted to export. This might change with TAMS III. Paging @graememk who probably knows more about it.

Nalz

https://www.boards.ie/discussion/comment/120292882#Comment_120292882

Nope. Works in I.T, has 8 pv panels and 2 batteries (5kwh each) since this time last year

graememk

https://www.boards.ie/discussion/comment/120292882#Comment_120292882

Tams 3 still has the "must consume 100% of power generated " stipulation. I think it's to do with the EU funding.

Briefly looked into it for an outfarm(plenty of space, but don't use much power, eg lights on the rare occasion we are there at night and a well pump. )

but to make that work it would need to be 80-90% export , also no issue with tax as it's an income to the business.

Regarding tams. Once the grant is paid.. it's not hard to remove the export limit. Also a lot of farms are classed as domestic/tied to a dwelling house. So there's deemed export there too.

Nalz

All the TAMs stuff etc is going over my head, I must read up more... but the long and short of it is there's not nor never been a cap of the amount of money you can get from sending back to the grid

DC999

Are you looking to get solar yourself?

Ignore the TAM grant - only for farms / certain large scale solar setups. Your neighbour has 8 panels, so won't be TAM. If you're asking for you as you're getting solar, as @con747 says 'The only cap I know of is the tax free up €200 for domestic installs after that you should declare it as income.'

Until about 6 months go you didn't get paid for unused excess. But you do now, called FIT (feed in tariff) - it's a credit on your electricity bill. So that might be what the neighbour refers too as they got setup at a time without those payments.

Nalz

https://www.boards.ie/discussion/comment/120294592#Comment_120294592

Yep we're getting solar. 18 panels, no battery (not yet anyway) a zappy and an eddy. Ground mounted system south facing

DC999

https://www.boards.ie/discussion/comment/120297991#Comment_120297991

Class, you'll have a good setup so. Pure South produces a wild amount. I've E/W split and my output is much lower than South. But still delighted to have it and best we can do with the roof we have.

I've no battery either now. Zappi and Eddi are your battery in a sense as can send excess into car and hot water tank. I'd suggest hold off on the battery for at least a few months and see how it all behaves. Others will have a different view I'm sure. If EV is in the driveway when it's daylight, it will hoover up the excess. You can decide the priority on Zappi or Eddi in terms of which gets the excess 1st.

Nalz

https://www.boards.ie/discussion/comment/120298342#Comment_120298342

Thanks DC999 - hope to get up and running soon! Excited!!

Nalz

We're up and running. I've seen 6kwh generated from my 18 panels but nothing over that. Is that capped somehow?

The Eddi is fantastic!

Still know very little about the whole thing and read so much conflicted things especially about whether to buy a battery or not!

Also we can't guess if the rate back to the grid will rise or fall in the coming months/years!

A lot to read up on and consider.

slave1

If you have anything above your inverter rating being generated then the inverter will “ignore”, this is called clipping e.g. 10kW being generated by panels being fed into a 6kW inverter means 6kW is your max

Nalz

https://www.boards.ie/discussion/comment/120348153#Comment_120348153

Thank you. Makes sense now I'm reading up on that. I let my wife and the salesguy do all the work. I'm wondering is it worth upgrading to a 10kwh inverter? Only found website with cost differences... 300 quid in the difference between 6 and 10kwh inverter?

con747

https://www.boards.ie/discussion/comment/120348259#Comment_120348259

The maximum allowed by ESBN on an NC6 domestic installation is 6kW but you can get an NC7 form which allows up to 50kW but it costs nearly 1k. There are ways to use all the excess power with other inverters that others here can explain better than me!

idc

https://www.boards.ie/discussion/comment/120349208#Comment_120349208

And the max is actually less than 6kW. ESBN allows 25A which works out at less than 6kW at 230V. But most people have been installing 6kW inverters but after May they will no longer accept 6kW inverters (28A). see here Micro-Generators (esbnetworks.ie)

Nalz

https://www.boards.ie/discussion/comment/120353233#Comment_120353233

Erm, remember I'm new and green to this, so when you say "no longer accept" what do you mean? Thanks!

con747

https://www.boards.ie/discussion/comment/120353758#Comment_120353758

They mean in a couple of months the rules change so you will only be able to install a 5kw inverter on an NC6 form so to go higher you will need to get the NC7 form which costs just under €1000.

slave1

FFS!

ELM327

I was seeing 8kWp peaks today, midday, 8.2kWp array with a 6kW solis hybrid inverter. 6kW to the house and 2kW to the battery. Still exporting zero.

Nalz

Two follow on noob questions, I'm sorry in advance

(a) if you have a 6kwh inverter and your panels pull more, say 8kwhs, if you have a battery does the 2kwh go to that, and if you don't have a battery it's wasted and doesn't go to the grid?

(b) anyone that has a 6kwh inverter now on a NC6 will continue to work like it is currently after May this year? The change will only affect new customers post May?

Thanks

ELM327

https://www.boards.ie/discussion/comment/120357526#Comment_120357526

a - 6kW inverters can pull up to and above 8kW depending on voltage. I saw 8.07kW today from my 8.2kWp arrays on a 6kW inverter

b- yes only new customers

idc

https://www.boards.ie/discussion/comment/120357526#Comment_120357526

Will answer (b) from the ESBN website if you got approved for 6kW inverter before May that is fine you can continue to use it.

Granolite

https://www.boards.ie/discussion/comment/120358022#Comment_120358022

Saw this today as well when sun was at its optimal orientation this afternoon. I have a 5kWh inverter paired up with a 5.6kWh array and was generating just over 5.8kW PV side (DC ) and 5.55kW AC side. Do cool temperatures help in terms of reducing voltage?

graememk

https://www.boards.ie/discussion/comment/120358498#Comment_120358498

Yes, the hotter the panel gets the worse it performs.

The rating of the inverter is the most you can get out of it on the ac side. Be it from solar or batteries or both.

Moreilly

https://www.boards.ie/discussion/comment/120358022#Comment_120358022

Probably a silly question but - Regarding the change of 6kWh inverters not being allowed after may , I've recently got one of these and am running a 22x400 panels with it, if my inverter goes kaput in a year or two can I replace it with the same inverter or do I have to downgrade to the 5kWh one, which then in turn would probably raise issues with the amount/VOC of the panels I currently have driving it ?

slave1

6kW inverters will be allowed after May, just NC7 required.

It's a crock on behalf of the esb, our cables can easily take constant 12kW 24/7 if/when required but we can't put 6kW back now from May without spending €1k+

DC999

https://www.boards.ie/discussion/comment/120360331#Comment_120360331

There should be no change with a like-for-like warranty replacement, that's only my view. Don't sweat about it, you might donkeys years from the inverter. I've only heard of 1 or 2 dying on this forum in the year I've been here - so failure rate is low.

If you have a 1.6 litre car and engine dies and is replaced with a 1.6 litre engine, it's still a 1.6 litre engine. It's not a 1.4 or 2L one - get what I mean?

idc

https://www.boards.ie/discussion/comment/120360331#Comment_120360331

I expect that as you originally got permission for 6kWh prior to May then you would be allowed replace with same/similar.

ELM327

https://www.boards.ie/discussion/comment/120360331#Comment_120360331

I just wouldnt mention anything to ESB and do it anyway

ELM327

https://www.boards.ie/discussion/comment/120360402#Comment_120360402

15kW ;)

And I can kinda see their point. My 6kW inverter was sending back nearly 7kW yesterday (I had to turn off and on battery for 5 mins to reset some stuff) and if their limit is already pushed at 6, I can't imagine they like 7!

Nalz

Interestingly enough, on my myenergi app the highest I see when sun is bright as bright is 6kwh. I've yet to see it go 0.1 over that

bullit_dodger

https://www.boards.ie/discussion/comment/120360758#Comment_120360758

I don't believe the problem is the cables, it's more about balancing the phases back at the substation. The more you allow people to export, the harder it (potentially) is to do that balancing. Typically your average estate in Ireland will have house #1 on phase 1, house #2 on phase 2, house #3 on phase 3 and then the cycle repeats.

In an ideal world everyone who has solar in the estate will be equally distributed across the phases. In reality that is statistically unlikely. NC7 isn't auto-approved as someone will have to look at the math and see if they can handle the export on that specific phase. So your €900 euros that you pay is for someone to look/see the loading and figure out if there's going to be a problem. Least that's my understanding of it.

ELM327

https://www.boards.ie/discussion/comment/120391046#Comment_120391046

Yes that's it in a nutshell re the NC7. Just saying that the immediate thing people worry about import or export is their own cable and then in house wiring like the CU and main fuse. As you say these are unlikely the limiting factor.

I'm debating going for the NC7 myself, after the energia day night EV tariff contract expires in July. The NC7 will give me a higher MEC, and then either a higher deemed FIT or - more likely - they will require me to get a smart meter and I will have metered export

slave1

My issue with the NC7 is you have to hand over a grand and only AFTER that are you exposed to esbnetworks who will soley determine what capital works are required and they have exclusivity on this and all at their pricing.

They could come back with a bill in the thousands and then your decide not worth it and your grand is gone.....

ELM327

Yes, that is an issue, but the transformer and local distribution grid capacities are available online so you'd have a good idea in advance whether the local transformer has slots available or not

But I agree, it's very cloak and dagger. If the FIT payments look to continue long term I'll pivot my "get 100% off grid and remove the ESB cable" aim to instead focus on making as much profit as possible from FIT and move to NC7.