ESB Inverter limits & exceeding with large array.

QweenBea

I'm going to be looking at getting in solar next year when we get an EV. We're expecting to use about 10-11,000kWh a year once we start charging from home.

I was hoping to get enough panels to cover this usage (around 12-15kw of panels), but from what I'm hearing, due to the ESB 5kW inverter limit, we'd only really be allowed to install around 8kw of panels.

Is there no way to increase this? Is there maybe some sort of inverter that will limit feedback to ESB at their 5kw limit, while feeding any excess into another inverter, our batteries or heating?

idc

For NC6 micro-generation strictly speaking ESBN does not allow for export limitation devices (even though most modern inverters include this), additionally the sum total of all inverters must not exceed 25A (5kW is not the limit its the total amps at 25A)

Microgeneration (esbnetworks.ie)

NC7 is mini-generation and that allows for inverters over 25A limit and export limitation. (this has a cost of almost 1000 just for them to investigate if your house/local substations/etc can support you exporting a higher amount)

Mini-Generation | ESB Networks

QweenBea

Thanks for that.

I heard that NC7 is risky, you pay €1000 non-refundable, and there's a risk they'll decline it.

If approved though, would that need ESB to come out and do some work on the lines or meter, or is just a simple matter for them to check if everything in place and capable of the higher amperage?

Before applying, is there anything we can do to check before spending €1000?

graememk

Yeah 8-9kwp is about the oversize limit you can do on a 5kw inverter (there is 1 5.5kw out there, Sunsynk)

Car charging is likely to be mostly off peak charging too, (eg A day Night meter, Or Nightsaver as its normally called)

Solar for charging the car is only good if the car is actually at home during the day. Oversizing will mean that the inverter will clip on the really good days, but will generate more on the cloudy days.

I would start with just staying with an NC6 install, get the feel of the system, and possibly be able to find gaps, or impovements, you can investigate a NC7.

Anything not grid tied doesnt count on a NC6, eg charge controllers, charging a battery that is then connected to a grid tied inverter.

GReid2005

https://www.youtube.com/watch?v=RIsd_WYiC7k&ab_channel=Enteligent-HarnessMoreSolar

https://www.youtube.com/watch?v=oomhefjdQaU&ab_channel=SolarSurge

These 2 links might help in your decision making, they relate to residential DC coupled EV chargers launching later this year and next year. So in essence you could make do with a 5kw inverter as it would just direct DC to the EV charger, you'll just need to find an inverter with a large oversize capacity.

I have a 11.7KW array pencilled in for install in early October, I've gone with a Sungrow SH5.0RS Hybrid Inverter as it has an oversize capacity of 240% which means it can handle 12kw of DC once the voltage limit isn't exceeded as this voids the warranty. I'm planning on installing a DC EV charger once they become available in the Irish market as well as a DC coupled Heat Pump sometime in the near future.

slave1

There’s a lot of folk here waiting for the first successful NC7, I’d say plenty would pay the €1k fee but the unknown capital costs etc at 100% ESB discretion is very concerning

TerraSolis

https://www.boards.ie/discussion/comment/121019839#Comment_121019839

My NC7 has just come good - I'll make a thread on it soon. I have lots to share that I think will be helpful for others.

Calahonda52

At the risk of stating the obvious, OP have you a monthly output from the PV array overlaid with a month estimated power requirement split between day, after dark and EV.

This, IMO, is essential data.

I do a lot of BERs for PV install companies and every house that has an EV has been told that charging it is the man, so does that mean on sunny days you don't drive

[There is a // with free juice on Saturdays... know a family who now stay home every Saturday: 10+ clothes washes, 4 dish washes, multiple hrs on the tumbler dryer and batch cooking for the week and wash the dogs.]

While the following analogy is not perfect, but there are //'s, when I started work for an energy company some time ago, dusk to dawn lighting projects were being rejected on the assumption that all the juice would be on the night rate, so made the payback look poor enough.

I crunched the numbers for daylight hours(or PV output hours) , per day for 365 days for a specific location, against the day/night rate schedules and it showed that close to 60% of the juice for dusk to dawn was at day rate.

This piece will impact your pricing work

TerraSolis

https://www.boards.ie/discussion/comment/121020024#Comment_121020024

https://www.boards.ie/discussion/2058310631/nc7-an-epic-saga/p1?new=1

QweenBea

https://www.boards.ie/discussion/comment/121020100#Comment_121020100

Our usage might be a bit unusual, as it'll be fairly evenly spread throughout the day. We have two of us working from home, the OH working nights, me at days and soon another will be doing college from home. Weekends might be the only time we see the traditional day/night splits.

Considering the NC6 limits, I'm begining to think we'll increase our battery size to something hefty (maybe 15-20kWh if affordable) to soak up the cheap night rates from ESB, and then top-up any remaining needs during the day from solar.

icylava

https://www.boards.ie/discussion/comment/121017192#Comment_121017192

Similar thoughts here! I just got started looking around. Have you progressed on your NC7 application? Anything to look out?