ESBN New Regulations on NC6 Form on 6kW 25amp Inverters May 31/2023

con747

I thought it would save others posting in numerous threads in relation to this, if they posted their queries here people may be able to advise in one thread.

Link https://www.esbnetworks.ie/new-connections/generator-connections-group/micro-generators-

DC999

Team in ESB that manage the NC6 forms from the installer are networkservicesbureau@esb.ie

Btw, I asked my installer for a copy of the NC6 confirmation from the ESB. Which they gave me. I did that as some people here had issues that ESB said it was never submitted and installer said it was

the_amazing_raisin

What are the new regulations?

con747

https://www.boards.ie/discussion/comment/120367246#Comment_120367246

No new 6kW inverters above 25amps allowed. I just added the link to opening post.

dumb_parade

But why is ok to have an existing 6kw inverter in use, but not be able to add one after that date. Surely the installed ones are the issue, if over 25 amps.

bullit_dodger

https://www.boards.ie/discussion/comment/120367305#Comment_120367305

The problem is more for future planning rather than today. Right now there are what(?) 25,000-30,000 households in Ireland with solar out of 2.4m homes. So just 1% or so. The main issue as I understand (and I may be wrong here) is that ESB need to be able to "balance the phases" at the substations when there are potentially 10-20% of people with solar in say 5 years time. The more people are allowed to export (5Kw verses 6Kw) etc....the harder potentially it maybe to do that balancing.

For comparison, I remember hearing that people in the north are only allowed export 3.8Kw or so? Is that right?

con747

https://www.boards.ie/discussion/comment/120367340#Comment_120367340

Yep. https://www.nienetworks.co.uk/connections/generation-connections/micro-scale/statement-on-changes-to-g98-microgeneration-limits#:~:text=The%20G98%2FNI%20limits%20are,kW%20for%20three%20phase%20installations.

the_amazing_raisin

https://www.boards.ie/discussion/comment/120367340#Comment_120367340

I assumed it was just that some 6kVA inverters are actually over 25A which is over 6kVA.

Specifying 25A is just under 6kVA and will ensure the export is below 6kVA even if the inverter is slightly over voltage (since the inverter has to be over 230V to export power)

I guess earlier ones are exempt because there were a lot of inverters that had 6kVA on the nameplate but when you dig into the datasheet it's actually over that. Since installers were none the wiser, ESBN is giving them a pass on older installations

waterwelly

Any link to an ESB networks actual statement on this?

bullit_dodger

https://www.boards.ie/discussion/comment/120367736#Comment_120367736

1st post in this very thread ?!

Ha Long Bay

https://www.boards.ie/discussion/comment/120367736#Comment_120367736

https://www.esbnetworks.ie/new-connections/generator-connections-group/micro-generators-

For the Solis 6K

Jonathan

Some interesting additions to Grid Standards in the latest 3.9.0 release of Solis Cloud.

EN50549IE (blue) was added a couple releases ago as an Irish variant of EN50549.

ESB-Micro and ESB-Mini (red) are new and might be the 25A limited/unlimited versions respectively. These grid standards obviously require an inverter firmware update, but I don't know which version they were added in.

silver_sky

https://www.boards.ie/discussion/comment/120479248#Comment_120479248

I've the latest Solis firmware on my 6kW hybrid, updated only yesterday. It's 470044. I can have a look if I get a chance to go up in the attic.

What menu is the standard in on the inverter?

Jonathan

https://www.boards.ie/discussion/comment/120480183#Comment_120480183

Advanced -> Select Standard

See page 35/36. https://www.ginlong.com/uploads/file/Solis_Manual_RHI(3-6)K_5G_EUR_V1,5(20220516).pdf

Did you ask for that f/w update or are you the Solis guinea pig now?

silver_sky

https://www.boards.ie/discussion/comment/120482729#Comment_120482729

I asked due to an issue with a previous firmware. I've been dealing with one of their techs in China who is quite good. I'll take a look tomorrow at the inverter.

Chris_5339762

What I've also seen on this forum but not in this thread is that the 6kW max export is based on THEORETICAL export. They assume that every dump load that you install to stop export is broken. So if you want 7kW of power say and can absolutely guarantee that you'll never exceed 6kW via a dump load, they won't accept that.

Nelbert

The whole thing is very Irish. From a networks point of view 2 next door neighbours pre and post install... Isolation etc. requirements remain the same as both current levels can do serious damage.

A practical view would have looked at the submitted NC6 forms (am I mad to think they have a database of them.....) seen the most prominent inverters at the 6kW and matched the restriction to that (so likely around 28a). This just seems like a "this is the rule because we say so" approach with no consideration for what's already in the wild.

bullit_dodger

https://www.boards.ie/discussion/comment/120494134#Comment_120494134

Agreed, "technically" there are better solutions - but the reality in deploying such a diverse pool is different. You can imagine the chaos that would ensue where "My mate Billy down the road got a 6Kw inverter, why am I not allowed to get the same? Why is Billy special?" and then the arguments trying to explain phase balancing to some gombean who can barely wire a plug.

As I understand it (and I may be wrong) the main issue is balancing the phases when there is significant export from the houses back at the substations. Now at the moment the saturation of solar is low in Ireland (~2% of houses), it probably doesn't matter too much if it's 6Kw or even 10Kw. But when saturation is 10-20%, it's going to matter a lot if they allow 6Kw or lowering it to 5Kw. Then there is the grid standards. Most inverter companies have the same hardware, but just apply a config file to the inverter to specify the max voltage allowed, max export, etc. So you can imagine the chaos of supporting different inverter configs for different streets, which will change over time as more (or less) people get solar. Nahh, on the surface it's very Irish, but there's a good background story there that they want to get right I think.

Maybe I'm wrong.

Murt2

https://www.boards.ie/discussion/comment/120494671#Comment_120494671

In an ideal world, it would be for balancing reasons. Unfortunately the real reason, the suppliers don't want to have to pay Billy who can output 10kW or more an hour for most of a summers day. He would eventually build up such a huge credit that he could get rid of his PV and still have free power for the rest of his life. The easiest way to prevent this, is limit Billy to a max of 6kW.

bullit_dodger

https://www.boards.ie/discussion/comment/120494959#Comment_120494959

Well it's hard to see how that's true on a number of fronts. First of all it's not the suppliers who are introducing the 5Kw limit. It's "ESB networks" and they have no vested interest in the end user game. People of course will say that they are all in cahoots, and fair enough, but the suppliers if anything are probably not too bothered one way or the other - at least not at the moment. The penetration of solar in the marketplace is like 2% of houses, the other 98% are unchanged and that's where the bulk of the wonga is.

The math doesn't add up either. How often (really) will your inverter be operating at over 5Kw? Maybe 1-2 hrs on a few of the very brightest days of the year. Let's put a number on it. 30 say 40 days? So they'd be diddling people out of 1Kw in production for maybe 2 hrs a day for 40 days. 80 units maybe? And you will have to have more than 6Kwp in panels. So that narrows it down to another subsection of the solar community further.

Don't get me wrong, bigger is better.... so 6kw is better than 5Kw (:-) .... but to be fair, it's not as if most people would actually notice I think.

Murt2

https://www.boards.ie/discussion/comment/120495245#Comment_120495245

Actually the biggest supplier in the country is Electric Ireland, they and ESBN are practically the same company.

If you've a 12kWh array, a 6kWh invertor will be maxed nearly all the time. But of course we're limited to 6KW inverters, so a waste of time and money having a very large array. In the US now, I've seen 12kW arrays supplying over 18,000 kWh a year at latitudes similar to ours. Most states have export limits far higher than ours, or none at all.

dumb_parade

Is there anything stoping me removing my 5kw inverter and installing a 7kw one instead, apart from the incorrect nc6 documentation?

Murt2

https://www.boards.ie/discussion/comment/120495321#Comment_120495321

Nothing, you'll just have to set it to 6kWh max export. They'll know very quickly if you've a smart meter and are pumping out 7kW.

bullit_dodger

https://www.boards.ie/discussion/comment/120495292#Comment_120495292

Fair points, but it's like comparing apples and oranges. It's not a fair comparison to compare a semi-detached house in Tallaght to a ranch in Denver Colorado :-)

Again, I'm with you. I'd like a bigger inverter too - but what I'm saying is that the math means that for 90+% of people with solar, they'll be oblivious to the change. The vast (vast) majority of people don't have more than 7Kwp or so and as previously I mentioned they'll probably lose 80Kwhr or so a year.

People with larger arrays, sure they are more penalized, but there are alternative avenues to go via NC7 for example, or as you say go on the sneak and get a bigger inverter and/or run 2x inverters in parallel. Your out on your own though doing that and running with the risks that may ensue.

Even for larger arrays like 8kwp-9.6Kwp, you would still benefit in being larger for a lot of the year even if your limited to 5Kw e.g. Oct-Mar where your producing more, but still not hitting the limit. 24 panels x 400w = 9.6Kwp would be the limit though for most inverters with 600vdc input, so really it's that small percentage of people who are in that 7kwp->9.6Kwp range, but it's not a huge impact

Murt2

https://www.boards.ie/discussion/comment/120495512#Comment_120495512

Oh yeah, for most the difference between 7 an 6 won't be noticeable. Twice the the size now is a very different story.

I've an 8kW array. Most of the time it's throttled to 6.4kW during the summer if the battery is full. I could fit a 12kW array on my south facing side, but again, a waste of money, because I'll only see the 'benefits' in the deep winter when it's dark most of the time. Whatever you generated in the summer with 6kW, you can at least double it if you could export 12kW or more.

NC7 is 3 phase, and they'll get you on usage when you don't pull enough to justify it.

It's all about money! Nothing as 'noble' as load balancing.

bullit_dodger

But that's just it, while it's easy to think it, I don't believe it is about money....ESB networks and or suppliers out to capitalize somehow. Take your own example, your "capped" or clipped at 6.4kw. You've 8Kwp in panels, so assuming your panels were at 100% your forcibly "dropped" 1.6Kw in production

Since you mentioned your battery is full, you'd be exporting at say 8Kw instead of 6.4Kw.....so you'd be getting a FIT rate for that 1.6Kw extra @ ~€0.20/unit. How long are you clipped at 6.4Kw, maybe 3 hrs? And let's say we get 30 days of those glorious sunshine from Apr - Sept? I think 30 days is probably generous, but let's run with 30 days

So 30 days x 3 hrs x 1.6Kw @ €0.20 = €28/year

So if you had an inverter capable of 8Kw you'd make an extra €28 a year. Hardly seems worth it from their perspective. Again, I'm in your camp, absolutely would like a higher capacity inverter but the math would point to it only having marginal benefit. Maybe I'm wrong in my math?

Interested in thoughts here?

Murt2

https://www.boards.ie/discussion/comment/120495752#Comment_120495752

I used to work for ESBN, I know what I'm talking about.

And we're talking 12Kw not 8. Anyway, Ireland gets about 1100 to 1600 hours of full sun averaged across the country a year. With south facing you get about 60% of that. So we'll split it 1300 X0.6 = 780, assuming no self usage of course.

780X 6.4 = 4992 x 21 cent = €1,048.32

780x 8= 6240 x 21 cent = €1,310.40 Delta: €262.08

780 x 12 = 9360 x 21 cent = 1,965.60 Delta: €917.28

That's just for one house on full sun hours, for one year, on average. Are you starting to see why it's money that's the real issue?

graememk

https://www.boards.ie/discussion/comment/120495577#Comment_120495577

NC7 is single phase too.

Murt2

https://www.boards.ie/discussion/comment/120495891#Comment_120495891

My mistake, it allows for both. Strange, why bother with the NC6 form then?

graememk

https://www.boards.ie/discussion/comment/120495920#Comment_120495920

Nc7 costs €1000 without any guarantees of approval,

Nc6 is free, basically a notification to esbn

Murt2

https://www.boards.ie/discussion/comment/120496190#Comment_120496190

Yep, money again!

Sligobuck

I used to work for ESBN, I know what I'm talking about. 🤣🤣

Murt2

https://www.boards.ie/discussion/comment/120496279#Comment_120496279

See anything wrong with my math? Yeah, I did. Did you?

bullit_dodger

My analysis was more to your specific case of 8Kwp being clipped to 6.4Kwp. Sure, when you start talking about 12Kwp it (the 5-6Kw limits) starts to get more punitive, but then you could start to say why stop at 12Kwp, why not 20Kwp.....or 50Kwp? Most people can't get more than 24 panels (9.6Kwp) on a single inverter as they are dc voltage limited - without spending crazy money (looking at you unkel - LOL!) - so I think 9-10Kwp is about the max that virtually everyone in this forum will have. There's a few outliers, but the OP was more about the general rule of 5Kw limits.

I must admit I'm not seeing the money aspect. I don't say that I think your wrong Murt only that I'd don't follow the math you were using above. Can you clarify?

Where it breaks down I think, is that while your right Ireland does indeed get between 1100-1600 hrs of sunshine (link) that all isn't directly facing fixed solar panels. If you had 2x axis solar trackers i guess you could use that number, but full sunshine at 9am isn't the same as full sunshine at 1pm on a south facing panel. Your not getting clipped at 9am are you? Even though Ireland might be in "full sunshine" so to speak. So the monies, I think, are a lot less than that.

No?

Murt2

"but full sunshine at 9am isn't the same as full sunshine at 1pm on a south facing panel. Your not getting clipped at 9am are you? Even though Ireland might be in "full sunshine" so to speak. So the monies, I think, are a lot less than that."

That's why I've the 60% utilization factor on South facing panels. The math is right. BTW, mine are south facing, I get 6kW by 10:30 at this time of the year.

These lifers are trying to keep themselves in the cushy number, and spout this nonsense to the clueless politicians, who of course couldn't care less anyway because they get their big dividend every year, the more the people pay, and the less they get paid, that more kickbacks to the government.

idc

Just curious how does this translate to other countries? eg northern ireland only allow less than 3/4kW ?? My own inverter 5kW mentions for the german market its limited to approx 4.5kW.

Murt2

https://www.boards.ie/discussion/comment/120496685#Comment_120496685

Look back about 15-20 years in the German market. Home owners were making a small fortune. Suppliers didn't like that....

buzz11

https://www.boards.ie/discussion/comment/120495348#Comment_120495348

How do they know? and is it just smart meters that would flag it?

Murt2

https://www.boards.ie/discussion/comment/120496732#Comment_120496732

Well the smart meter would give them your export profile, and would show 7kW if you ever exported that much.

Yes, currently that's the only way they would know, unless they had access to your inverter data, which they shouldn't have. They wouldn't really care, because without a smart meter you won't get paid for the 7kW anyway, you get a guesstimate.

graememk

https://www.boards.ie/discussion/comment/120496685#Comment_120496685

Yeah UK and NI have a notify and fit of 16 amps, although there is routes like the nc7 there now but it's prior approval

bullit_dodger

Still not seeing the math. We may have to "agree to disagree" here :-)

Your saying your being clipped at 10:30am (and I believe you), but at 10:30am your not being clipped the full amount at that time (i.e. the difference in total Kwp to your inverter size). What I mean by that is you might have 6.5Kwp available but clipped to 6.4Kw, meaning your only losing that 100w at that time out of 6.5Kw you could potentially get.

10 mins later that will probably rise on the sine wave curve to 6.6Kw available but again your being clipped to 6.4kw. Really there's only 1-2 hours either side of solar noon where your actually being severely clipped from your theoretical max of 8Kw. And at that worst case it's like 1.6Kw out of the 8Kw (assuming you could get all 8Kw)

The hours of sunshine doesn't take into consideration any angle of incidence to the panel. A bight full hour of sunshine in Winter isn't the same as full hour of sunshine in May with the slant angles, so using the hours of sunshine that way doesn't take slant angels into consideration. Panel temp also makes a difference too. August has more hours of sunshine than April but typically we produce more in April as the panels are cooler, so you'll be less likely to experience clipping.

All told while bigger inverters help reduce clipping and I personally would perfere a bigger inverter myself, the effect isn't as much as you would think.

Murt2

What are you on about, I've factored it in. You not getting it isn't my problem. You get about 60% utilization factor on a normal 30 to 45 degree roof ( sun angles and all accounted for) of full sun hours with a south facing array. What about that don't you understand?

I generated about 6,500 kWh last year, my math worked out that nearly 5000, KWh are from full sun hours. The rest came from overcast hours. Explain how that's wrong.

graememk

https://www.boards.ie/discussion/comment/120496806#Comment_120496806

Easier just to use the JRC estimate

https://re.jrc.ec.europa.eu/pvg_tools/en/#PVP

Murt2

https://www.boards.ie/discussion/comment/120496857#Comment_120496857

Cheers. I've used it before, it's saying I should have gotten more than 6,500kWh.....Oh well!

bullit_dodger

https://www.boards.ie/discussion/comment/120496806#Comment_120496806

Relax man - no one is having a go at you. I didn't say your wrong. I'm just trying to understand your logic. Additionally if I'm wrong, I've no issue in admitting that and I've learnt something new. That's a win for me as far as I'm concerned.

What I'm saying is that in your case (assuming you had an unlimited inverter) a normal solar generation profile for a south array on a perfect day would look something like this.....

So if we introduce the inverter clipping for 6.4Kwp at 10:30am it starts to look something like this.

The shaded area is the production that your losing and that area is actually quiet small compared to the overall area under the curve (your total production). So being clipped to 6.4kw on a 8Kwp system it sounds like it's bad, but it's really not that impactful. For example at 11am your "clipped", but only a few 100's watts as it's not got to noon yet where you'd lose 1.6kw

Only on the "very perfect days" of the year will you lose any significant production, probably 2-3Kwh out of 40-50Kwh. If you lower the inverter limit to 5kw, natrually that shaded area gets bigger, but even still it's still the smaller of the two.

Then the other factor is how many of those "great sunshine days" where you would see any clipping we get a year. We can argue the case - I reckon 30-40 probably. I remember March last year was awesome, but I'd say outside of that we get maybe 4-5 days a month of solid blue skies maybe

Murt2

Use the tool graemeuk linked. It confirms what I'm saying. If anything, it's more generous on the generation lost than I was.

bullit_dodger

It's a great tool PVGIS. I use it all the time.

Unfortunately the tool doesn't answer the question at hand. The tool will tell you what the production is for a panel with a specific orientation (azimuth) and slope, for the year. It has no knowledge of any inverters it's attached to, so it can't tell you the negative effect of a inverter clipping the production. There are many many days a year where (say) 10Kwp in panels would not be clipped on a 6kw (or even) a 5kw inverter. Those days your array would still produce full output and be counted in the totals for the year with either 5kw or 6kw inverter....

This goes back to the original point of the 1st post. Yeah, a 5Kw isn't as good as a 6Kw, but in reality the drop in production to the user at the end of the year will not be that bad. Which do you want? Of course your want the 6Kw, because bigger is better, but the overall % difference in output for the year is probably of the order of single digit % up until to go you to 8-9Kwp. At that stage your well into the heavy "enthusiast" ballpark.

Murt2

Put in 6.4kWh, then 8. It will give you about 1500 kWh lost. Inverter by damned, that's the difference in production. Sun angles, sun hours the works taken into account. Which is close to what I worked it out as. The states don't have this BS, but of course Ireland and the EU by extension always talk a great game.

bullit_dodger

But that's not "clipping" Murt, due to inverter sizing. That's just the difference in production due to the greater size of the panels. That's a completely different thing from clipping and why you can't use PVGIS (or the sunshine hours) to work that out. For example, which I hope will show what I mean.....

I highlighted January in both cases. The 8.0Kwp array (of course) produces some 50Kwh more for January than the 6.4Kwp does - but has anyone EVER seen "clipping" on a array in the middle of January in Ireland with the sun 20deg above the horizon?! Just doesn't happen. Sun is too low on a slant angle.

So in this case, if you had 8Kwp in panels in January......you would still generate the same if you have coupled that to a 5kw inverter, or a 6Kw inverter as the inverter isn't the bottleneck. When the clipping does start (March?) then you will see it start to happen a bit more every day. Maybe you might get it for a few minutes in March, maybe a little longer in April, etc, but it's only in June that you would see your inverter clip any decent amount and at that, for maybe 3-4 hrs you'll only lose a significant fraction of 1.6Kw on the table. The other 12-13 or so hours you'll have captured everything within limits.

When you look at the impact space verses the overall year, imapct is low

Murt2

It is due to clipping! 2kW per hour generated on a cloudy day from an 8kW array is still 2 kilowatts on an 8kW inverter or a 6 kW inverter! The overwhelming difference between the two, 6.4 to 8kW is peak full sun production. And guess what the clipped 1.6kW equates to about 1500kWhs a year, just like I said. Not the pitiful amount you're claiming with no evidence to back it. You're just repeating the same already refuted nonsense.

And with that, I'm done. Talking to a wall would be more productive.

bullit_dodger

Clipping in January - in Ireland? For reals?

Don't take my word for it and perhaps this would help explain it better than I have so far. (414) Solar Clipping Explained - YouTube

Again, I'm not saying that they are equal, of course you want the larger inverter - but the effect is a lot less than you think. The idea that your being cheated out of 1000's of Kwh with 5Kw over a 6kw is simply just not true.