Limiting Export

[ecogeorge]

Evening all , have a friend who consumes a very large amount of electricity (milks dairy cows) who is looking at a groundmount system array starting at say 10kw.
I have produced output figures using PVGIS .
How ever he is on a very poor single phase supply -uses a rotary converter to generate 3 phase where required. Western power won't accept any more connection than 3.6kw and are trying to get him to upgrade their transformer.
I am aware of current limiting inverters -say 5kw panels and only 3.6kw output but he wants full use of all available and to be honest think he will export zero.
How do we get around that ?
What devices / components does he need ?
cheers George

[ecogeorge]

https://www.sma-uk.com/solar-systems/ex ... ation.html
Found this but looks a bit technical !!
George

[nowty]

Depends upon what the DNO is actually saying.

Is it, you cannot export more than 3.68kW or you cannot fit more inverter power whether its G100 capped to 3.68kW or not.

He may have simply had the initial brush off.

[Stinsy]

As nowty says, there are several routes:

1) He can have a 3.6kW hybrid inverter. Most allow 8kW (or similar of panels), and he can add more power feeding directly into batteries.

2) He can have a g100-compliant inverter bigger than 3.6kW. This is certified to never export more than 3.6kW. So he’d be able to have a 10kW inverter (or whatever) to power his milking machines and everything else.

With both of the above options the DNO are not allowed to say no!

The difficult parts of solar PV are having space for the panels and the installation costs. I guess your farmer has loads of space and can do the installation himself. So he should go as big as he has space for IMO. A mega array might produce more power than he can use when the sun shines but panels are cheap, an oversized array will do the business when it is cloudy too…

[Oldgreybeard]

You can also get an approved export limitation panel installed if the chosen inverter does not meet the requirements: https://www.g59projects.co.uk/g100-expo ... solutions/

I looked at this as there were initially questions asked by my DNO about the actual approval of the Sofar ME3000SP and whether or not it could be set to zero export (it can, but the DNO seemed to be very poorly informed about these things).

[nowty]

As nowty says, there are several routes:

1) He can have a 3.6kW hybrid inverter. Most allow 8kW (or similar of panels), and he can add more power feeding directly into batteries.

2) He can have a g100-compliant inverter bigger than 3.6kW. This is certified to never export more than 3.6kW. So he’d be able to have a 10kW inverter (or whatever), power his milking machines and everything else.

With both of the above options the DNO are not allowed to say no!

The difficult parts of solar PV are having space for the panels and the installation costs. I guess your farmer has loads of space and can do the installation himself. So he should go as big as he has space for IMO. A mega array might produce more power than he can use when the sun shines but panels are cheap, an oversized array will do the business when it is cloudy too…

I don’t believe 2) is true, the DNO might allow it, it might not depending upon the circumstances. A G100 compliant setup wont export more than 3.68kW for more than 5 seconds. That might not be acceptable to the DNO in all cases.

[Oldgreybeard]

My experience was that the people I spoke with at the DNO were pretty clueless and didn't understand how battery storage inverters worked at all. I can't see why they should be worried at all about a 5 second delay as they are allowed to exceed the set limits for supplies for longer than this whenever they wish. Our old supply used to regularly brown out to the point where some stuff would stop working for a few seconds yet the DNO just kept stating this was OK and within tolerance as far as they were concerned. Thankfully the problem went away when the nearby farm got a new supply run in. The problem had been the farm grain drier starting up and loading our supply down.

[Stinsy]

I don’t believe 2) is true, the DNO might allow it, it might not depending upon the circumstances. A G100 compliant setup wont export more than 3.68kW for more than 5 seconds. That might not be acceptable to the DNO in all cases.

Happy to be corrected. I thought G100 was "inform" rather than "ask permission".

[nowty]

I don’t believe 2) is true, the DNO might allow it, it might not depending upon the circumstances. A G100 compliant setup wont export more than 3.68kW for more than 5 seconds. That might not be acceptable to the DNO in all cases.

Happy to be corrected. I thought G100 was "inform" rather than "ask permission".

Both G99 and G99 Fast Track applications, with G100 compliance are both pre-install applications.

[Ken]

Dont go through brick walls -go round.

Will this really do what the customer expects. Dont they milk cows at the end of the days when solar is low/non existent.

Why is it that the DNO can supply 65A/100A but one cannot export that.

How much would it cost to have a 3ph supply put in as i have a feeling this is the better long term solution. Perhaps grants/subsidies available. Need to contact farmers union surely. The farmer can dig the trench for a cable.

Why not go for a full battery system not connected to mains. How many hours a day is milking operational. Run the morning milk off TOU tariff charging batts and evening milking on PV charging batts.