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

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 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?

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

1st post in this very thread ?!

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.

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.

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.

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

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

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?