Limiting Export

[Gareth J]

Find someone to speak to at Western power. There are very knowledgeable people there, my generally approachable, point of contact seems genuinely good at his job and keen to work with you.

Regarding how to limit export, it'll depend on what the DNO will let you get away with, which may depend on lots of things, they seem most focussed on the capacity of the inverter/s, and their failsafe scenarios (Gxx compliance).

Regarding a dairy farm, one of the biggest electric consumers will be milk cooling - big compressor heat pumps. This demand goes up with hotter weather. Ideal for solar. If he's really hamstrung for generator size, might be worth considering a standalone icebuilder and small battery setup to regulate charging. He might have the icebuilder and compressor/s anyway but can be used as on a direct expansion tank too, just needs to run through a plate heat exchanger. Potentially cheaper than the huge battery setup that'd be required and could be separated from the grid to get bigger capacity if needed.

Could I ask roughly where he is and who he's considering for his installation? If you know.

[Stinsy]

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.

The import/export discrepancy is due to "diversity" of consumption. Basically you can have 100 houses on the same transformer. They each consume 10kW from time to time. Eg if the washing machine heating element kicks in at the same time as the kettle and toaster are on, or if someone is using the electric shower, etc. However these are very short-lived occurrences and usage quickly drops back to a few hundred watts. This happens in all of the 100 houses, just not at the exact same time so the transformer never gets overwhelmed. Solar is different in that there is no diversity. The sun shines on all the houses at the same time, this can quickly overwhelm the transformer.

Getting 3-phase is cheap and easy if you have 3-phase running past your house. If you're more rural and are at the end of a long single (or split) phase 11kV line with a ropey old single-phase transformer, then you're looking at the thick end of 5-figures. I'm sure if 3-phase was simple or cheap to install it'd have been done decades ago.

[SafetyThird]

I've found Western Power to be excellent to deal with and very knowledgable. First thing I'd do is get someone out to do a site survey with you, that's what we did. I wanted to install 3 phase as the lines cross our property but apparently the place to connect in is several Km away and we were quoted approx £70k. We're at the very end of a split phase line and used to have a 16kva transformer on the pole. When some updates were done, we had that upgraded to 50kva at a cost of £2k as they were already doing the work.

Each time we've needed anything such as permission for the upgrades, PV install, GSHP install etc, they've been very helpful and the person who comes out to look at the property has understood what we're trying to do and generally come up with the best option possible.

I'd see if a site visit can be done before exploring any other options and get the farmer to talk it through with them directly.

[Tinbum]

Getting 3-phase is cheap and easy if you have 3-phase running past your house. If you're more rural and are at the end of a long single (or split) phase 11kV line with a ropey old single-phase transformer, then you're looking at the thick end of 5-figures. I'm sure if 3-phase was simple or cheap to install it'd have been done decades ago.

I was 3 poles away from 3 phase and requested a price many years ago which was ridiculous. Then about 10 years ago they came round saying that they were redoing all the poles from the sub station. I managed to get a couple of departments to talk to each other and they came up with another price, still expensive, but I managed to also get the transformer moved out of the garden and away from the house however I did all the trenching and ductwork. Now I'm moving the house to the transformer but that's another story.

If you find the right person at the DNO they will help.

[Oldgreybeard]

If you find the right person at the DNO they will help.

This is absolutely true! My experience has been that DNOs have a lot of numpties that don't have a clue interspersed with a few very helpful and knowledgable people that go out of their way to sort things out. Sadly, finding the right person to talk to can be challenging. I managed it by accident, a contractor from the DNO was doing some work on our supply, I got talking with him over a mug of tea and he gave me the name and number of the "Mr Fixit" at the local DNO office. Brilliant bloke, had a pragmatic solution for pretty much anything.

[CrofterMannie]

Getting 3-phase is cheap and easy if you have 3-phase running past your house. If you're more rural and are at the end of a long single (or split) phase 11kV line with a ropey old single-phase transformer, then you're looking at the thick end of 5-figures. I'm sure if 3-phase was simple or cheap to install it'd have been done decades ago.

I asked SSE for a quote and it was going to be £150k, but that was nearly 10 years ago so it would probably be double that now.